Two major innovations in clothing in the 14th century were Buttons and knitting. Option c is correct.
The use of buttons became more widespread in the 14th century, and they were used for both practical and decorative purposes. Buttons made it easier to fasten and unfasten clothing, and they were also used to add embellishments to clothing.
Knitting also became more popular in the 14th century, and it allowed for the creation of new types of clothing, such as stockings and hats. Knitted clothing was warmer and more comfortable than woven fabrics, and it was also more stretchy, which allowed for a better fit.
The other options listed in the question, such as the zipper, bomber jacket, Macintosh, Velcro, snaps, polyester, and nylon, were not invented until much later, with most of them not appearing until the 20th century or later.
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Seth wants to create a replica of a doughnut for a rooftop sign for his bakery. The replica has a diameter of 18 feet. The diameter of the hole in the center is equal to the replica's radius.
Once the replica is built, Seth wants to string small lights around the outer edge. How long will the string of lights need to be?
A. Write a numerical expression for the length of the string of lights needed.
B. Simplify your expression. Use 3. 14 as an approximation for.
C. Explain how you got your answer.
To determine the length of the string of lights needed for Seth's doughnut replica, we can follow these steps:
A. The length of the string of lights needed can be expressed as the circumference of the doughnut replica. The formula for the circumference of a circle is C = 2πr, where C represents the circumference and r represents the radius.
B. Given that the diameter of the replica is 18 feet, the radius would be half of that, which is 9 feet. Using the approximation 3.14 for π, we can simplify the expression: C = 2 × 3.14 × 9.
C. Simplifying further, we have C = 56.52 feet. Therefore, the string of lights needed for Seth's doughnut replica would need to be approximately 56.52 feet long.
In summary, the length of the string of lights needed for the doughnut replica is approximately 56.52 feet. This is calculated by using the formula for the circumference of a circle, substituting the radius of the doughnut replica, and simplifying the expression using the approximation 3.14 for π.
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Predict the major product for the reaction. The starting material is an alkene where carbon 1 has a cyclohexyl and methyl substituent, and carbon 2 has a methyl and hydrogen substituent. This reacts with C l 2 in the presence of ethanol. Draw the major product.
The major product of the reaction will be the 1,2-dichloroalkane .
The reaction is likely a halogenation reaction, where the alkene reacts with [tex]Cl_2[/tex] in the presence of ethanol as a solvent. Specifically, the double bond in the starting material will undergo electrophilic addition to one of the chlorine atoms, forming a carbocation intermediate. This intermediate can then undergo a nucleophilic attack by the chloride ion, resulting in substitution of the original double bond with a new carbon-chlorine bond.
In this case, the major product of the reaction will be the 1,2-dichloroalkane, where both carbons of the original double bond have been replaced with chlorine atoms.
The reaction can be represented as follows:
[tex]CH_3[/tex]
|
[tex]CH_3C[/tex] -- [tex]CH(C_6H_1_1)Cl[/tex] + [tex]Cl_2[/tex] + EtOH → [tex]CH_3C[/tex] --[tex]CH(C_6H_1_1)Cl_2[/tex] + HCl + EtOH
|
H
Therefore, The cyclohexyl and methyl substituents on carbon 1 and the methyl and hydrogen substituents on carbon 2 will remain unchanged in the final product. Hence, the major product of the reaction will be the 1,2-dichloroalkane .
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a current of 4.75 a4.75 a is passed through a cu(no3)2cu(no3)2 solution for 1.30 h1.30 h . how much copper is plated out of the solution? Number g
The current of the 4.75 A is passed through the Cu(NO₃)₂ the solution is for the 1.30 h. The amount of the copper is the plated out is 7.32 g.
The current = 4.75 A
The time = 1.30 h = 4680 h
The molar mass of the copper = 63.55 g/mol
The total charge passed in the solution :
Q = I × t
Q = 4.75 A × 4680 sec
Q = 22,167 C
The number of moles :
n = Q / F
n = 22,167 C / (96485 C/mol × 2)
n = 0.115 mol
The amount of the copper is as :
m = n × M
m = 0.115 mol × 63.55 g/mol
m = 7.32 g
The amount of the copper is 7.32 g with the molar mass of 63.55 g/mol.
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One gram of iron(ii) chloride has a higher mass percentage of chloride than 1 gram of iron(iii) chloride.a. Trueb. False
The one gram of iron(II) chloride has a higher mass percentage of chloride than one gram of iron(III) chloride. The answer is True.
In iron(II) chloride (FeCl₂), the mass percentage of chloride is lower than in iron(III) chloride (FeCl₃) when comparing 1 gram of each compound.
The correct answer is: a. True.
Iron(II) chloride, also known as ferrous chloride, has a chemical formula FeCl2, which means it contains one iron ion (Fe2+) and two chloride ions (Cl-) in its structure. On the other hand, iron(III) chloride, also known as ferric chloride, has a chemical formula FeCl3, which means it contains one iron ion (Fe3+) and three chloride ions (Cl-) in its structure.
The molar mass of each ion and add them up to get the molar mass of the compound. Then, we divide the molar mass of chloride by the molar mass of the whole compound and multiply by 100 to get the percentage.
For iron(II) chloride, the molar mass of Fe2+ is 55.85 g/mol, and the molar mass of two Cl- ions is 2 x 35.45 g/mol = 70.90 g/mol. Therefore, the molar mass of FeCl2 is 55.85 + 70.90 = 126.75 g/mol. The mass of chloride in one gram of FeCl2 is 2 x 35.45 g/mol = 70.90 g/mol, which means the mass percentage of chloride is 70.90/126.75 x 100% = 55.97%.
For iron(III) chloride, the molar mass of Fe3+ is 55.85 x 3 = 167.55 g/mol, and the molar mass of three Cl- ions is 3 x 35.45 g/mol = 106.35 g/mol. The molar mass of FeCl3 is 167.55 + 106.35 = 273.90 g/mol. The mass of chloride in one gram of FeCl3 is 3 x 35.45 g/mol = 106.35 g/mol, which means the mass percentage of chloride is 106.35/273.90 x 100% = 38.84%.
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An electrochemical cell is based on the following two half-reactions: oxidation: Sn(s)→Sn2+(aq, 1.50 M )+2e− reduction: ClO2(g, 0.180 atm )+e−→ClO−2(aq, 1.65 M ) Compute the cell potential at 25 ∘C.
E°cell = Standard state cell potential
R = 0.0821 Lkmol^-1K^-1 (gas constant)
T = 298 K
n = Number of electrons transferred in balanced redox reaction = 2 (from the half-reactions)
F = 96485 C/mol (Faraday's constant)
Q = Reaction quotient = [Sn^2+] [ClO2^-] / [Sn] [ClO2]
1. Standard state cell potential (E°cell): Since we have Sn/Sn^2+ and ClO2/ClO2^- half-cells, E°cell = E°Sn/Sn^2+ - E°ClO2/ClO2^-
= -0.76 V - 0.94 V = -1.7 V
2. Reaction quotient (Q):
[Sn^2+] = 1.50 M
[ClO2^-] = 1.65 M
[Sn] = 1 M (assumed, since Sn is solid)
[ClO2] = 0.180 atm = 0.180 M
So Q = (1.50 M) (1.65 M) / (1 M) (0.180 M) = 9:1
3. Substitute into cell potential formula:
Ecell = -1.7 V - (0.0821 Lkmol^-1K^-1 * 298 K) * ln(9)
Ecell = -1.7 V - 0.0613 * ln(9)
Ecell = -1.76 V
So the cell potential at 25°C is -1.76 V
Let me know if you have any other questions!
c) is there any evidence for exo- vs. endo- in the nmr? explain why/why not.
There is evidence for exo- vs. endo- in the NMR, as the chemical shift of a proton is affected by the position of substituents on a cyclohexane ring.
Exo- and endo- refer to the position of substituents on a cyclohexane ring. Exo- means that the substituent is on the outside of the ring, while endo- means that the substituent is on the inside of the ring. In NMR spectroscopy, the chemical shift is a measure of the magnetic environment around a particular nucleus.
When a substituent is in the exo- position, it is farther away from the other atoms in the ring. This means that it experiences a slightly different magnetic environment compared to an endo- substituent, which is closer to the other atoms in the ring. As a result, the chemical shift of an exo- substituent will be slightly different from that of an endo- substituent.
This difference in chemical shift can be used to identify the position of substituents on a cyclohexane ring. By comparing the chemical shifts of different protons in the NMR spectrum, it is possible to determine whether a substituent is in the exo- or endo- position.
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Please sort the following items as examples of either assimilatory or dissimilatory processes. Items (6 Items) (Drag and drop into the appropriate area below)1. Nitrification 2. Nitrogen fixation 2. Chemoautotroph y 3. Photosynthesis 4. Decomposition 5. Aerobic respiration of organic compounds Type of process Assimilatory 6. Dissimilatory
The sorted processes Assimilatory: Nitrogen fixation, Photosynthesis, Chemoautotrophy. Dissimilatory: Nitrification, Decomposition, Aerobic respiration of organic compounds.
Assimilatory and dissimilatoryAssimilatory and dissimilatory processes are two types of metabolic pathways that describe how microorganisms use or produce different compounds to carry out their life processes.
Assimilatory processes are those that incorporate or assimilate various substances into the biomass of the organism for growth and reproduction. Examples of assimilatory processes include nitrogen fixation, photosynthesis, and chemoautotrophy. On the other hand, dissimilatory processes are those that produce energy through the breakdown of organic or inorganic matter into simpler compounds.
Examples of dissimilatory processes include nitrification, decomposition, and aerobic respiration of organic compounds. Understanding the difference between these processes is crucial for understanding how microorganisms transform nutrients in various ecosystems and the role they play in biogeochemical cycles.
Therefore, the sorted processes:
Assimilatory:
Nitrogen fixationPhotosynthesisChemoautotrophyDissimilatory:
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How many grams of thallium may be formed by the passage of 7,678 amps for 3.23 hours through an electrolytic cell that contains a molten Tl(I) salt.
Approximately 190 grams of thallium may be formed by the passage of 7,678 amps for 3.23 hours through an electrolytic cell that contains a molten Tl(I) salt. Faraday's Law, which states that the amount of substance produced by electrolysis is directly proportional to the quantity of electricity passed through the cell.
The formula for this is: moles of substance = (current x time) / (96500 x n) where current is measured in amperes, time is measured in seconds, n is the number of electrons transferred per mole of substance, and 96500 is the Faraday constant.
In this case, we are given the current (7,678 amps) and the time (3.23 hours, which is 11,628 seconds). We also know that the substance being electrolyzed is Tl(I) salt, which has a charge of +1. Therefore, n = 1.
Using the formula above, we can calculate the moles of thallium produced: moles of Tl = (7678 x 11628) / (96500 x 1) = 0.930 moles. To convert moles to grams, we need to multiply by the molar mass of thallium, which is 204.38 g/mol: grams of Tl = 0.930 moles x 204.38 g/mol = 190.04 grams
Therefore, approximately 190 grams of thallium may be formed by the passage of 7,678 amps for 3.23 hours through an electrolytic cell that contains a molten Tl(I) salt.
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Approximately 182 grams of thallium (Tl) may be formed by the passage of 7,678 amps for 3.23 hours through an electrolytic cell that contains a molten Tl(I) salt.
To calculate the amount of Tl formed, we need to use Faraday's law of electrolysis, which states that the amount of substance formed during electrolysis is directly proportional to the quantity of electricity passed through the cell.
The formula for Faraday's law is:
Amount of substance = (Current × Time × Atomic weight) / (Valency × Faraday constant)
In this case, the current is 7,678 amps, the time is 3.23 hours, the atomic weight of Tl is 204.38 g/mol, the valency is 1, and the Faraday constant is 96,485 coulombs/mol.
Plugging these values into the formula, we get:
Amount of substance = (7,678 × 3.23 × 204.38) / (1 × 96,485) = 182.04 g
Therefore, approximately 182 grams of thallium may be formed by the passage of 7,678 amps for 3.23 hours through an electrolytic cell that contains a molten Tl(I) salt.
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Part A What volume of 0.155 M NaOH is required to reach the equivalence point in the titration of 15.0 mL of 0.120 M HNO3 ? ► View Available Hint(s) 2.79 x 10mL 11.6 mL 15.0 mL 19.4 ml Submit
Answer:
(c) Find moles of NaOH in 5 mL using molarity (0.125 mol/1 L * 0.005 L). Set up reaction and BAA table to find how much acid reacted is left after reaction. Then, calculate total volume at this point, and find [HC₂H₃O₂] and [NaC₂H₃O₂] using remaining moles and total volume.
Explanation:
The volume of 0.155 M NaOH required to reach the equivalence point is 11.6 mL.
The balanced chemical equation for the reaction between NaOH and HNO3 is:
NaOH + HNO₃ -> NaNO₃ + H₂O
From the equation, we can see that 1 mole of NaOH reacts with 1 mole of HNO3. At the equivalence point, the moles of HNO₃ will be equal to the moles of NaOH added. We can use this information to calculate the volume of NaOH required to reach the equivalence point.
First, we need to calculate the moles of HNO₃ in 15.0 mL of 0.120 M solution:
moles of HNO₃ = Molarity * Volume in liters
moles of HNO3 = 0.120 M * (15.0 mL/1000 mL) = 0.00180 moles
Since 1 mole of NaOH reacts with 1 mole of HNO3, we need 0.00180 moles of NaOH to reach the equivalence point.
Now we can use the concentration of NaOH to calculate the volume required:
moles of NaOH = Molarity * Volume in liters
0.00180 moles = 0.155 M * (Volume/1000 mL)
Volume = 11.6 mL
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When moderately compressed, gas molecules have attraction for one another Select the correct answer below: O a small amount of O a large amount of no O none of the above
When moderately compressed, gas molecules have a small amount of attraction for one another(A).
When gas molecules are compressed, their average distance from each other decreases. This means that the molecules are more likely to interact with each other due to their increased proximity.
The strength of these interactions depends on the specific gas and the degree of compression, but in general, the intermolecular forces are relatively weak.
At low pressures and temperatures, the gas molecules are widely dispersed and have little interaction with each other, while at high pressures and temperatures, the molecules are packed more closely together and have a greater likelihood of colliding and interacting.
Overall, the level of attraction between gas molecules is considered to be moderate when they are moderately compressed. So a is correct option.
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Determine the molar solubility of BaF2 in a solution containing 0.0750 M LiF. Ksp (BaF2) = 1.7 × 10-6, QA 2.3 × 10-5 M ○ B. 8.5 × 10-7 M Oc, 1.2 × 10-2 M O D.0.0750 M CE 3.0 × 10-4 M
To determine the molar solubility of BaF2 in a solution containing 0.0750 M LiF, we need to consider the Ksp (solubility product constant) of BaF2 and the common ion effect from the presence of LiF.
Firstly, BaF2 dissociates as follows:
BaF2(s) ⇌ Ba²⁺(aq) + 2F⁻(aq)
Now,
Ksp = [Ba²⁺][F⁻]²
= 1.7 × 10⁻⁶
Let x be the molar solubility of BaF2. In the presence of 0.0750 M LiF, the equilibrium concentrations will be [Ba²⁺] = x and [F⁻] = 0.0750 + 2x.
Substitute these values into the Ksp expression:
1.7 × 10⁻⁶ = x(0.0750 + 2x)²
Since x is very small compared to 0.0750, we can approximate (0.0750 + 2x)² ≈ (0.0750)² to simplify the equation:
1.7 × 10⁻⁶ = x(0.0750)²
x ≈ 3.0 × 10⁻⁴ M
So, the molar solubility of BaF2 in the 0.0750 M LiF solution is approximately 3.0 × 10⁻⁴ M (Option E).
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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be _____.Zn(s) + ReO4-(aq) → Re(s) + Zn2+(aq) (acidic solution)A. 2B. 7C. 8D. 16
The correct coefficient for zinc is "8", since we need to multiply the coefficient by the subscripts in the formula of Zn. the correct answer is option (D) 16.
To balance the given redox equation, we need to assign oxidation numbers to each element first. Here, zinc has an oxidation number of 0 since it is in its elemental state, and the oxidation number of oxygen in ReO4- is -2. Therefore, the oxidation number of Re is +7.
Next, we can balance the equation using the half-reaction method. First, we balance the oxygen atoms by adding H2O to the side of the equation that needs more oxygen. This gives us:
Zn(s) + ReO4-(aq) + 8H+(aq) → Re(s) + Zn2+(aq) + 4H2O(l)
Next, we balance the hydrogen atoms by adding H+ to the other side:
Zn(s) + ReO4-(aq) + 8H+(aq) → Re(s) + Zn2+(aq) + 4H2O(l) + 8H+(aq)
Now we can balance the electrons by multiplying the zinc half-reaction by 8:
8Zn(s) + ReO4-(aq) + 16H+(aq) → Re(s) + 8Zn2+(aq) + 4H2O(l) + 8H+(aq)
Therefore, the correct answer is option D.
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The balanced equation with smallest whole number coefficients is:
[tex]Zn(s) + 4H+(aq) + ReO4-(aq) → Re(s) + Zn2+(aq) + 2H2O(l)[/tex]
Therefore, the coefficient for zinc is 1.
To balance the redox equation in acidic solution, first, we write down the unbalanced equation:
Zn(s) + ReO4-(aq) → Re(s) + Zn2+(aq)
Next, we identify the oxidation states of each element in the equation:
[tex]Zn(s) → Zn2+(aq) (+2)[/tex]
[tex]ReO4-(aq) → Re(s) (+7)[/tex]
We can see that zinc is being oxidized (losing electrons) while rhenium is being reduced (gaining electrons).
To balance the equation, we add water molecules and hydrogen ions to balance the charge and oxygen atoms:
[tex]Zn(s) → Zn2+(aq) + 2e-[/tex]
[tex]ReO4-(aq) + 8H+(aq) + 3e- → Re(s) + 4H2O(l)[/tex]
Now, we balance the electrons by multiplying the half-reactions by appropriate coefficients:
[tex]Zn(s) + 4H+(aq) + ReO4-(aq) → Re(s) + Zn2+(aq) + 2H2O(l)[/tex]
The coefficient for zinc is 1, which is the smallest whole number coefficient.
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If, for a particular process, ΔH = -214 kJ/mol and ΔS = 450 J/mol.k the process will be: Select the correct answer below: O spontaneous at any temperature O nonspontaneous at any temperature O spontaneous at high temperatures O spontanteous at low temperatures
The correct answer to the question is: the process will be spontaneous at any temperature.
ΔG is the amount of energy available to do useful work in a system. It is related to ΔH and ΔS through the equation ΔG = ΔH - TΔS, where T is the temperature in Kelvin.
If ΔG is negative, the process is spontaneous (meaning it will happen on its own without any external energy input), and if ΔG is positive, the process is nonspontaneous (meaning it will not happen on its own without external energy input).
Using the given values of ΔH = -214 kJ/mol and ΔS = 450 J/mol.k, we can calculate ΔG at different temperatures. However, we first need to convert ΔH from kJ/mol to J/mol by multiplying by 1000:
ΔH = -214,000 J/mol
Now we can calculate ΔG at different temperatures using the equation above:
At 298 K (room temperature):
ΔG = -214,000 J/mol - (298 K)(450 J/mol.K) = -349,100 J/mol
Since ΔG is negative, the process is spontaneous at room temperature.
At a high temperature (e.g. 1000 K):
ΔG = -214,000 J/mol - (1000 K)(450 J/mol.K) = 36,000 J/mol
Since ΔG is positive, the process is nonspontaneous at high temperatures.
At a low temperature (e.g. 100 K):
ΔG = -214,000 J/mol - (100 K)(450 J/mol.K) = -229,500 J/mol
Since ΔG is negative, the process is spontaneous at low temperatures.
Therefore, the correct answer to the question is: the process will be spontaneous at any temperature.
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sodium sulfate has the chemical formula na2so4. based on this information, the formula for chromium(iii) sulfate is ____.
Answer:
Cr2(SO4)3
Cr +3 SO4-2
Criss Cross charges to get subscripts
Cr2(SO4)3
A gauge pressure is measuring 4. 66 atm of pressure inside a basketball. What is the absolute pressure inside the basketball?
The absolute pressure inside the basketball can be calculated by adding the atmospheric pressure to the gauge pressure. Atmospheric pressure is typically around 1 atm at sea level.
Therefore, the absolute pressure inside the basketball can be calculated as the sum of the gauge pressure and the atmospheric pressure.
In this case, the gauge pressure is given as 4.66 atm. Assuming atmospheric pressure is 1 atm, the absolute pressure inside the basketball would be:
Absolute pressure = Gauge pressure + Atmospheric pressure
Absolute pressure = 4.66 atm + 1 atm
Absolute pressure = 5.66 atm
Therefore, the absolute pressure inside the basketball is 5.66 atm. This represents the total pressure exerted by the gas inside the basketball, including both the gauge pressure and the atmospheric pressure.
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Propose a plausible mechanism for the following transformation. 1) EtMgBr 2)H3O+ . Identify the most likely sequence of steps in the mechanism: step 1: ____. step 2: ____. step 3: ____.
The given transformation involves the reaction of EtMgBr (ethylmagnesium bromide) followed by treatment with H3O+ (aqueous acid). This type of reaction is commonly known as an acidic workup.
The most likely sequence of steps in the mechanism for this transformation is as follows:
Step 1: Nucleophilic Addition
EtMgBr acts as a nucleophile and attacks the electrophilic carbon in the carbonyl group of the substrate. The mechanism involves the transfer of the ethyl group (-Et) from EtMgBr to the carbon atom, resulting in the formation of a tetrahedral intermediate.
Step 2: Protonation
In the presence of an acid such as H3O+, the tetrahedral intermediate is protonated. The acidic conditions provide a source of protons, and one of these protons is transferred to the oxygen atom of the tetrahedral intermediate. This step leads to the formation of an alcohol.
Step 3: Deprotonation
In the final step, another molecule of H3O+ acts as a proton donor and deprotonates the alcohol, resulting in the formation of the final product. This step restores the acidity of the reaction medium.
Overall, the proposed mechanism for the given transformation involves nucleophilic addition of EtMgBr, followed by protonation and subsequent deprotonation of the intermediate formed, leading to the desired product.
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For the following reaction:
N2+3H2⟶2NH3
What is the change in free energy inkJmol? The relevant standard free energies of formation are:
ΔG∘f,N2=0kJmolΔG∘f,H2=0kJmolΔG∘f,NH3=-16.3kJmol
Your answer should include three significant figures.
The change in free energy for this reaction is -32.6 kJ/mol.
For the given reaction, N2 + 3H2 ⟶ 2NH3, we can determine the change in free energy (ΔG) using the standard free energies of formation (ΔG°f) provided for each component.
The change in free energy for the reaction is calculated as:
ΔG° = Σ (ΔG°f, products) - Σ (ΔG°f, reactants)
For this reaction, we have:
ΔG° = [2 × (ΔG°f, NH3)] - [(ΔG°f, N2) + 3 × (ΔG°f, H2)]
Given the standard free energies of formation:
ΔG°f, N2 = 0 kJ/mol
ΔG°f, H2 = 0 kJ/mol
ΔG°f, NH3 = -16.3 kJ/mol
Substituting these values, we get:
ΔG° = [2 × (-16.3)] - [(0) + 3 × (0)]
ΔG° = -32.6 kJ/mol
Therefore, the change in free energy for this reaction is -32.6 kJ/mol, expressed to three significant figures.
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how many photons are emitted from the laser pointer in one second? hint: remember how power is related to energy.
The number of photons emitted from the laser pointer in one second can be calculated using the power of the laser, the energy of the photons, and the relationship between power and energy.
The power of a laser pointer is typically measured in milliwatts (mW). Let's assume the laser pointer has a power output of 5 mW.
The energy of each photon is related to the wavelength of the laser light. Let's assume the laser pointer emits light with a wavelength of 650 nanometers (nm), which corresponds to red light. The energy of each photon can be calculated using the following formula:
E = hc/λ
Where E is the energy of each photon, h is Planck's constant (6.626 x 10⁻³⁴ joule seconds), c is the speed of light (299,792,458 meters per second), and λ is the wavelength of the light in meters.
Plugging in the values for h, c, and λ, we get:
E = (6.626 x 10⁻³⁴ J s)(299,792,458 m/s)/(650 x 10⁻⁹ m) ≈ 3.04 x 10⁻¹⁹ joules
Now, to calculate the number of photons emitted from the laser pointer in one second, we can use the following formula:
Number of photons = Power/ Energy per photon
Plugging in the values for power and energy per photon, we get:
Number of photons = (5 x 10⁻³ W) / (3.04 x 10⁻¹⁹ J) ≈ 1.64 x 10¹⁶photons/second
Therefore, approximately 1.64 x 10¹⁶ photons are emitted from the laser pointer in one second.
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According to lewis theory which one is acid or base
AlBr3
According to Lewis theory, an acid is a substance that can accept a pair of electrons, while a base is a substance that can donate a pair of electrons. In the case of AlBr3 (aluminum bromide), it acts as a Lewis acid.
Aluminum bromide is a compound composed of aluminum and bromine atoms a base is a substance that can donate a pair of electrons. In this compound, the aluminum atom has a partial positive charge, making it electron-deficient. It can accept a pair of electrons from a Lewis base. The bromine atoms, on the other hand, have lone pairs of electrons that they can donate to a Lewis acid, making them potential Lewis bases.
Therefore, in the Lewis theory, AlBr3 is considered an acid due to its ability to accept a pair of electrons from a Lewis base.
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Draw the product that valine forms when it reacts with di-tert-butyl dicarbonate and triethylamine followed by an aqueous acid wash.
You do not have to consider stereochemistry.
Do not draw organic or inorganic by-products.
Draw the product in neutral form unless conditions are clearly designed to give an ionic product.
Include cationic counter-ions, e.g., Na+ in your answer, but draw them in their own sketcher.
Do not include anionic counter-ions, e.g., I-, in your answer.
The reaction between valine and di-tert-butyl dicarbonate in the presence of triethylamine will form a tert-butyl valine intermediate, which can be hydrolyzed by aqueous acid to yield the final product, valine.
The reaction scheme is as follows:
Valine + di-tert-butyl dicarbonate → tert-butyl valine + di-tert-butyl carbonate
tert-butyl valine + H2O → valine + tert-butanol
The di-tert-butyl carbonate by-product is not drawn as it is not part of the final product.
The cationic counter-ion, triethylammonium (Et3NH+), is not drawn as it is not involved in the reaction.
When valine reacts with di-tert-butyl dicarbonate (Boc2O) and triethylamine, it forms a Boc-protected valine. The Boc group (tert-butoxycarbonyl) protects the amine group of valine by forming a carbamate.
After the aqueous acid wash, the product remains Boc-protected valine in its neutral form, as the acid wash doesn't remove the Boc group. The structure of the product is valine with a Boc group attached to the nitrogen atom of its amino group.
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230 90th undergoes alpha decay. what is the mass number of the resulting element?
The resulting element after the alpha decay of 230 90Th is 226 88Ra.
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle, which consists of two protons and two neutrons. The parent nucleus, in this case, is 230 90Th, which means it has 90 protons and 140 neutrons.
When it undergoes alpha decay, it emits an alpha particle, which means it loses two protons and two neutrons. This reduces its atomic number by two and its mass number by four.
So, the resulting element has an atomic number of 88 (90 - 2) and a mass number of 226 (230 - 4), which corresponds to the element radium (Ra). Therefore, the resulting element after the alpha decay of 230 90Th is 226 88Ra.
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A sample of an ideal gas at 1.00 atm and a volume of 1.45 was place in wait balloon and drop into to the ocean as the sample descended the water pressure compress the balloon and reduced its volume when the pressure had increased to 85.0 ATM what was the volume of the sample
The estimated volume of the gas sample when the pressure increased to 85.0 ATM is approximately 123.25 units.
Based on the given information and assuming the gas follows the ideal gas law, we can estimate the volume of the sample when the pressure increased to 85.0 ATM.
Using the ideal gas law equation (PV = nRT), where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature, we can rearrange the equation as:
V1/P1 = V2/P2
Given that the initial pressure (P1) is 1.00 ATM and the initial volume (V1) is 1.45, and the final pressure (P2) is 85.0 ATM, we can calculate the approximate volume (V2):
V2 = (V1 * P2) / P1
V2 = (1.45 * 85.0) / 1.00
V2 ≈ 123.25
Therefore, the estimated volume of the gas sample when the pressure increased to 85.0 ATM is approximately 123.25 units.
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a solution of k3po4 is 38.5y mass in 850 g of water. how many grams of k3po4 are dissolved in this solution?
Therefore, the mass of k3po4 dissolved in this solution is 38.5y grams.
To find the mass of k3po4 dissolved in this solution, we need to subtract the mass of water from the total mass of the solution.
Total mass of the solution = mass of k3po4 + mass of water
We are given the mass of water as 850 g. We do not have the value of the total mass of the solution or the value of y, so we cannot find the mass of k3po4 directly. However, we can set up an equation using the concentration of the solution to find the mass of k3po4.
The concentration of a solution is defined as the amount of solute (in this case, k3po4) per unit volume or mass of the solution. We can find the concentration of the k3po4 solution using the following formula:
Concentration = Mass of solute / Volume or mass of solution
We know that the concentration of the k3po4 solution is 38.5y / 850 g. We can rearrange the formula to solve for the mass of solute:
Mass of solute = Concentration x Volume or mass of solution
We are looking for the mass of solute, so we can substitute the values we have:
Mass of solute = (38.5y / 850 g) x 850 g
The units of grams cancel out, leaving us with:
Mass of solute = 38.5y
Therefore, the mass of k3po4 dissolved in this solution is 38.5y grams.
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If 7.40 g of O3 reacts with 0.670 g of NO, how many grams of NO3 will be produced? Identify the limiting reagent from the reaction.
2O3 + 3NO → 3NO3
O3 produces _____0.72____ grams of NO2
NO produces ________ grams of NO2
The limiting reagent (reactant) is-
The grams of NO3 produced in the reaction will be 0.72 g. The limiting reagent is NO.
First, we need to calculate the moles of O3 and NO using their molar masses. The molar mass of O3 is approximately 48 g/mol, and the molar mass of NO is approximately 30 g/mol.
The moles of O3 can be calculated by dividing the given mass of O3 (7.40 g) by its molar mass, which gives approximately 0.154 moles.
Similarly, the moles of NO can be calculated by dividing the given mass of NO (0.670 g) by its molar mass, which gives approximately 0.0223 moles.
Next, we can use the stoichiometric coefficients from the balanced equation to determine the moles of NO3 that can be produced from each reactant. According to the balanced equation, 2 moles of O3 react with 3 moles of NO to produce 3 moles of NO3.
From the calculated moles, we find that O3 can produce approximately 0.231 moles of NO3 (0.154 moles O3 × 3 moles NO3 / 2 moles O3).
On the other hand, NO can produce approximately 0.0335 moles of NO3 (0.0223 moles NO × 3 moles NO3 / 3 moles NO).
To convert the moles of NO3 to grams, we multiply by the molar mass of NO3, which is approximately 62 g/mol.
Thus, O3 produces approximately 0.72 grams of NO3 (0.231 moles NO3 × 62 g/mol).
Since NO produces a lesser amount of NO3 (0.0335 moles NO3 or approximately 2.08 grams), it is the limiting reagent in this reaction. The amount of NO3 produced is determined by the amount of NO available, and any excess O3 is left unreacted.
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Write the full electron configuration for S2- full electron configuration: What is the atomic symbol for the noble gas that also has this electron configuration? atomic symbol:
The full electron configuration for S2- is 1s2 2s2 2p6 3s2 3p6. The atomic symbol for the noble gas that also has this electron configuration is Ar, which stands for Argon.
Neutral sulfur (S) atom and then add 2 electrons to account for the 2- charge.
The atomic number of sulfur is 16, so a neutral sulfur atom has 16 electrons. The electron configuration for a neutral sulfur atom is:
1s² 2s² 2p⁶ 3s² 3p⁴
Now, to account for the 2- charge, we need to add 2 electrons to the configuration. This will give us:
1s² 2s² 2p⁶ 3s² 3p⁶
Therefore, This electron configuration corresponds to a noble gas, which is argon (Ar). The atomic symbol for the noble gas that has the same electron configuration as S2- is Ar.
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1 1 point Arrange the compounds in order of increasing number of hydrogen atoms/ions per formula unit. fewest 1 1 barium hydroxide i 2 ammonium carbonate 3 ammonium chlorate 4 lithium hydride C greatest Next
The compounds arranged in order of increasing number of hydrogen atoms/ions per formula unit are 1. Lithium hydride
2. Barium hydroxide , 3. Ammonium carbonate , 4. Ammonium chlorate.
Lithium hydride (LiH) has one hydrogen atom per formula unit.
Barium hydroxide ([tex]Ba(OH)_2[/tex]) has two hydrogen atoms per formula unit.
Ammonium carbonate (([tex]NH_4)2CO_3[/tex]) has four hydrogen atoms per formula unit, as there are two ammonium ions, each containing one hydrogen ion, and one carbonate ion, containing two hydrogen ions.
Ammonium chlorate ([tex]NH_4ClO_3[/tex]) has five hydrogen atoms per formula unit, as there is one ammonium ion containing one hydrogen ion, and one chlorate ion containing three hydrogen ions.
Therefore, the correct order from fewest to greatest number of hydrogen atoms/ions per formula unit is:
Lithium hydride < Barium hydroxide < Ammonium carbonate < Ammonium chlorate
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How many ketopentoses are possible? Write their Fischer projections, 25.45 One of the D-2-ketohexoses is called sorbose. On treatment with NaBH4, sor- bose yields a mixture of gulitol and iditol. What is the structure of sorbose? 25.46 Another D-2-ketohexose, psicose, yields a mixture of allitol and altritol when reduced with NaBH4. What is the structure of psicose?
There are three possible ketopentoses. Sorbose has the structure of D-fructose with a ketone group at C2. Psicose has the same structure as D-fructose.
the hydroxyl group at C3 replaced by a hydrogen atom. Ketopentoses are a class of five-carbon sugars that contain a ketone functional group. There are three possible ketopentoses: D-ribose, D-arabinose, and D-xylose. Sorbose is a D-2-ketohexose, which means it is a six-carbon sugar with a ketone group at the second carbon. When sorbose is reduced with NaBH4, it yields a mixture of two sugar alcohols, gulitol and iditol. Psicose is another D-2-ketohexose that yields a mixture of two sugar alcohols, allitol and altritol, when reduced with NaBH4. The structure of sorbose is identical to that of D-fructose, with a ketone group at C2 instead of a hydroxyl group. The structure of psicose is also the same as that of D-fructose, but with the hydroxyl group at C3 replaced by a hydrogen atom.
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An ideal gas with an initial volume of 2. 05 L is cooled to 11 °C where its final volume is 1. 70 L. What was the temperature initially (in degrees Celsius)?
The initial temperature of the gas was approximately -73 °C.
To find the initial temperature of the gas, we can use the combined gas law, which states that the ratio of the initial pressure to the initial temperature is equal to the ratio of the final pressure to the final temperature, assuming the amount of gas and the gas constant remain constant.
Given:
Initial volume (V1) = 2.05 L
Final volume (V2) = 1.70 L
Final temperature (T2) = 11 °C
Rearranging the combined gas law equation, we can solve for the initial temperature (T1):
T1 = (T2 * V2 * V1) / (V1 - V2)
Substituting the given values into the equation, we find:
T1 = (11 °C * 1.70 L * 2.05 L) / (2.05 L - 1.70 L)
Evaluating the expression, the initial temperature is approximately -73 °C.
Therefore, the initial temperature of the gas was approximately -73 °C.
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A student wrote the following response to the question, What are elodea plants
made of?
Elodea plants are made of cells, cell walls, cytoplasm, and chloroplasts.
His friend told him that he forgot to include the levels of complexity.
Improve on the first student’s response, keeping in mind his friend’s suggestion
Elodea plants are composed of various levels of complexity, including cells, tissues, organs, and organ systems. At the cellular level, they consist of cells with cell walls, cytoplasm, and chloroplasts. The different levels of complexity contribute to the overall structure and functioning of the plant.
Elodea plants exhibit hierarchical levels of organization, from cells to organ systems. At the cellular level, they are composed of plant cells, which are enclosed by cell walls made of cellulose. The cell walls provide structural support and protection. Within the cells, the cytoplasm contains various organelles, including chloroplasts. Chloroplasts are responsible for photosynthesis, where light energy is converted into chemical energy to produce glucose.
Moving beyond the cellular level, elodea plants also possess tissues, which are groups of cells with similar functions. These tissues work together to perform specific tasks. For example, the leaf tissue contains specialized cells that facilitate gas exchange and photosynthesis. Organs, such as leaves, stems, and roots, are formed by different tissues working in coordination. Each organ has specific functions, such as nutrient absorption in roots or photosynthesis in leaves.
At the highest level of complexity, elodea plants have organ systems. The combination of roots, stems, and leaves forms the shoot system, responsible for water and nutrient transport, support, and photosynthesis. The root system anchors the plant, absorbs water and minerals, and stores nutrients.
In summary, elodea plants exhibit various levels of complexity, ranging from cells to organ systems. Understanding these levels helps us appreciate the intricate structure and functioning of these plants.
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an air-track glider is attached to a spring. the glider is pulled to the right and released from rest at tt = 0 ss. it then oscillates with a period of 2.40 ss and a maximum speed of 50.0 cm/scm/s.
The spring constant is 5.76 m/s² × m, the amplitude of the oscillation is 14.6 cm, and the potential energy of the system is 0.0609 J.
Based on the information given, we know that the air-track glider is attached to a spring, and when it is pulled to the right and released from rest at t = 0 s, it oscillates with a period of 2.40 s and a maximum speed of 50.0 cm/s.
To find more information about the system, we can use the formula for the period of a spring-mass oscillator, which is:
[tex]T=2\pi \sqrt{m/k}[/tex]
where T is the period, m is the mass of the glider, and k is the spring constant.
We can rearrange this formula to solve for k:
[tex]k=\frac{2\pi }{T} m[/tex]
Substituting the given values, we get:
k = (2π/2.40)² × m
k = 5.76 m/s²× m
Next, we can use the formula for the maximum speed of an oscillator:
v_max = Aω
where v_max is the maximum speed, A is the amplitude of the oscillation (which is equal to the maximum displacement from equilibrium), and ω is the angular frequency, which is related to the period by:
ω = 2π/T
Substituting the given values, we get:
50.0 cm/s = A × 2π/2.40
A = 14.6 cm
Finally, we can use the formula for the potential energy of a spring-mass oscillator:
[tex]U=\frac{1}{2} kA^{2}[/tex]
Substituting the values we found, we get:
U = 1/2 × 5.76 m/s² × (0.146 m)²
U = 0.0609 J
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