Answer:
a. Molarity of NaCl solution = 5.64 * 10⁻⁷ mol/L
b. molarity of Na⁺ = 5.64 * 10⁻⁷ mol/L
c. molarity of Cl⁻ = 5.64 * 10⁻⁷ mol/L
d. Osmolarity = 1.128 osmol
e. mass percent of NaCl = 3.30 * 10⁻⁶ %
f. parts per million NaCl = 0.033 ppm NaCl
g. parts per billion of NaCl = 33 ppb of NaCl
h. From the values obtained from e, f and g, the most convenient to use and understand is parts per billion as it has less of a fractional part to deal with especially since the solute concentration is very small.
Explanation:
Molarity of a solution = number of moles of solute (moles)/volume of solution (L)
where number of moles of solute = mass of solute (g)/molar mass of solute (g/mol)
a. Molarity of NaCl:
molar mass of NaCl = 58.5 g/mol, mass of NaCl = 33.0/1000) g = 0.033g
number of moles of NaCl = 0.033/58.5 = 0.000564 moles
Molarity of NaCl solution = 0.000564/1000 = 5.64 * 10⁻⁷ mol/L
b. Equation for the dissociation of NaCl in solution: NaCl ----> Na⁺ + Cl⁻
From the above equation I mole of NaCl dissociates to give 1 mole of Na⁺ ions,
Therefore molarity of Na⁺ = 1 * 5.64 * 10⁻⁷ mol/L = 5.64 * 10⁻⁷ mol/L
c. From the above equation I mole of NaCl dissociates to give 1 mole of Cl⁻ ions,
therefore molarity of Cl⁻ = 1 * 5.64 * 10⁻⁷ mol/L = 5.64 * 10⁻⁷ mol/L
d. From the above equation, dissociation of NaCl in water produces 1 mol Na⁺ and 1 mole Cl⁻.
Total number of particles produced = 2
Osmolarity of solution = number of particles * molarity of siolution
Osmolarity = 2 * 5.64 * 10⁻⁷ mol/L = 1.128 osmol
e. mass of percent of NaCl = {mass of NaCl (g)/ mass of solution (g)} * 100
density of water = 1 Kg/L
mass of water = 1 Kg/L * 1000 L = 1000 kg
1Kg = 1000 g
Therefore mass of solution in g = 1000 * 1000 = 1 * 10⁶ g
mass percent of NaCl = (0.033/1 * 10⁶) * 100 = 3.30 * 10⁻⁶ %
f. Parts per million of NaCl:
parts per million = 1 mg of solute/L of solution
One thousandth of a gram is one milligram and 1000 ml is one liter, so that 1 ppm = 1 mg per liter = mg/Liter.
Since the density of water is 1kg/L = 1,000,000 mg/L
1mg/L = 1mg/1,000,000mg or one part in one million.
parts per million NaCl = 33.0/1000 L = 0.033 ppm NaCl
g. Parts per billion = 1 µg/L of solution
1 g = 1000 µg
therefore, 33.0 mg = 33.0 * 1000 µg = 3.30 * 10⁴ µg
parts per billion of NaCl = 3.30 * 10⁴ µg/1000 L = 33 ppb of NaCl
h. From the values obtained from e, f and g, the most convenient to use and understand is parts per billion as it has less of a fractional part to deal with especially since the solute concentration is very small.
During lab, students mixed two solutions of soluble ions in a ceramic well to determine if a precipitate forms.
Write the dissolution reaction for the ionic solids below. (Use the lowest possible coefficients. Include states-of-matter under the given conditions in your answer.)
(a) Ca(NO3)2
(b) Na3PO4
The two solutions, when mixed, will have two cations and two anions.
(c) Based on your lab results, enter the cation and anion for which a precipitate will form. (Separate substances in a list with a comma.)
(d) Write the net precipitation reaction that occurs. (Use the lowest possible coefficients. Include states-of-matter under the given conditions in your answer.)
Answer:
(a) [tex]Ca(NO_3)_2(s)\rightarrow Ca^{2+}(aq)+2NO_3^-(aq)[/tex]
(b) [tex]Na_3PO_4(s)\rightarrow 3Na^++PO_4^{3-}[/tex]
(c) [tex]Ca^{2+} \ and \ PO_4^{3-}[/tex]
(d) [tex]3Ca^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Ca_3(PO_4)_2(s)[/tex]
Explanation:
Hello,
In this case, the balanced dissolution reactions are:
(a) [tex]Ca(NO_3)_2(s)\rightarrow Ca^{2+}(aq)+2NO_3^-(aq)[/tex]
(b) [tex]Na_3PO_4(s)\rightarrow 3Na^++PO_4^{3-}[/tex]
Moreover, when calcium nitrate and sodium phosphate react a double displacement reaction occurs, forming calcium phosphate, which is actually the precipitate due to its low solubility in water, and sodium nitrate:
[tex]2Na_3PO_4(aq)+3Ca(NO_3)_2(aq)\rightarrow 6NaNO_3(aq)+Ca_3(PO_4)_2(s)[/tex]
Thus, the precipitate is formed by:
(c) [tex]Ca^{2+} \ and \ PO_4^{3-}[/tex]
Finally, the net precipitation reaction shows the involved cation, anion and final product:
(d) [tex]3Ca^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Ca_3(PO_4)_2(s)[/tex]
Regards.
The first three excited states of the nucleus Au-199 (gold) are at 0.075 Mev, 0.320 Mev and 0.475 MeV. If all transitions between theses states and the ground state occurred, what energy/wavelength gamma rays would be observed?
Answer and Explanation:
The computation of the energy or wavelength gamma rays observed is shown below:
Since the energy of gamma rays is higher than 0.10 MeV.
Now We have to calculate transitions in between the given levels of energy that correspond to this energy.
As per the given question, we have the following information
Ground state = E where E < 0.075 MeV
For Level 1 = 0.075 MeV
For Level 2 = 0.320 MeV
For Level 3 = 0.475 MeV
Now we have to take the below transitions:
1. [tex]3 \rightarrow 2[/tex]
Difference of energy is
= 0.475 - 0.320
= 0.155 MeV
This represents a gamma radiation
2. [tex]3 \rightarrow 1[/tex]
Difference of energy is
= 0.475 - 0.075
= 0.4 MeV
This represents a gamma radiation
3. [tex]3 \rightarrow ground[/tex]
Difference of energy is
= 0.475 - E > 0.155 MeV
This represents a gamma radiation
4. [tex]2 \rightarrow 1[/tex]
Difference of energy is
= 0.320 - 0.075
= 0.245 MeV
This represents a gamma radiation
5. [tex]2 \rightarrow ground[/tex]
Difference of energy is
= 0.320 - E > 0.245 MeV
This represents a gamma radiation
6. [tex]1 \rightarrow Ground[/tex]
Difference of energy is
= 0.075 - E < 0.10 MeV
This represents not a gamma radiation
We can see that there are 5 transitions that contain gamma rays
Given the following Fischer projection: Fischer projection for an entantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine oriented horizontally to the left and the hydroxide group oriented horizontally to the right. draw the perspective formula of the molecule. Be sure to correctly indicate stereochemistry in your answer.
Answer:
Explanation:
Stereoisomers are two or more atoms that have the same bonding order of atoms but there is a difference spatial arrangement of the atoms in space.
A plane of symmetry divides a molecule into two equal halves.
A chiral stereoisomer are not superimposed on a mirror image , Hence they do not posses a plane of symmetry.
As a result to that. these non-superimposable mirror images are said to be Enantiomers.
However, a Fischer Projection emanates from a two - dimensional figure which is used for presenting a three - dimensional organic molecules.
From the given question;
Fischer projection for an enantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine oriented horizontally to the left and the hydroxide group oriented horizontally to the right.
we can sketch the way the enantiomer of 2-bromo-2,3-dihydroxypropanal can be seen like the one shown below:
CH₂OH
|
|
|
Br -------------|----------------OH
|
|
|
CHO
The objective of this question is to drawn the perspective formula of the molecule.
So , from the attached file below; we can see the perspective formula of the molecule in a well structured 3-D format.
g If a sample of 50 mL of ethyl benzene (bp = 136 C) was contaminated with 10 mL of ethyl acetate (bp = 77 C) what effect would this have on the boiling point measurement?
Answer:
melting point will be higher than that of pure ethyl acetate
Explanation:
Q#1 Give a combination of four quantum numbers that could be assigned to an electron occupying a 5p orbital.
Express your answers using one significant figures. Enter your answers separated by commas.
The answer n, l, ml, ms = 5,1,-1,0,or1,-1/2or+1/2
mastring chemistry says
"Incorrect; Try Again; 6 attempts remaining; no points deducted
Your answer does not have the correct number of comma-separated terms."
the same for q#2
Do the same for an electron occupying a 6d orbital.
Express your answers using one significant figures. Enter your answers separated by commas.
the answer n, l, ml, ms =6,0,1,2,-2,-1,0,+1,+2,+1/2or-1/2
Answer:
For an electron in 5p orbital
5,1,-1,+1/2
For an electron in 6d orbital
6,2,-2,+1/2
Explanation:
The term quantum numbers refers to a set of values that can be used to determine the region in space where it is likely to find an electron. This region in space where there is a high probability of finding an electron is known as an atomic orbital. An atomic orbital is actually a wave function according to the Schrödinger wave equation.
There are four quantum numbers used in describing an atomic orbital: the principal quantum number (n), the orbital angular momentum quantum number also called azimuthal or subsidiary quantum number (l), the magnetic quantum number (ml), and the electron spin quantum number (ms).
For a 5p orbital;
n= 5, l= 1, ml= -1,0,1 ms= +1/2 or -1/2
For 6d orbital;
n= 6, l= 2, ml= -2,-1,0,1,2, ms= +1/2 or -1/2
Since we are requested to use a four quantum number description that can be assigned to an electron in these levels;
For an electron in 5p orbital
5,1,-1,+1/2
For an electron in 6d orbital
6,2,-2,+1/2
g acetaminophen aspirin binder caffine A. The strong organic acid is __________________________________. B. The weak organic acid is __________________________________. C. The organic base is ____________caffeine______________. D. The neutral substance is _________binder____________.
Answer:
The most common analgesic tablets contains a mixture of caffeine, aspirin, acetaminophen, along with binder.
The binders are neutral substances that are employed to keep tablet intact during packaging, shipping and being swallowed. Examples of binder are silica gel, cellulose, starch etc.
And the remaining aspirin, acetaminophen and caffeine can be classified as strong acid, weak acid and base, respectively by merely observing functional groups they possess.
Explanation:
question
Acetominophen , Aspirin, Binder, ,
Identify the strong organic acid, weak organic acid, base and neutral substance isolated in these experiments.
The strong organic acid is __________________________________.
The weak organic acid is __________________________________.
The organic base is __________________________________.
The neutral substance is __________________________________
explanation
Aspirin contains -COOH making it strong acid than phenol compound
Acetominophen contains phenolic -OH, making it weak organic acid
Caffeine contains Nitrogen atoms whch can donate lonepair of H⁺ , this makes it basic
Spell out the full name of the compound.
Explanation:
Step one look for the longest chain of carbon atoms
Longest chain is 7 C atoms
Step 2 look for double bonds or others functional groups
it is present in 3rd carbon
Therefore IUPAC name is 3-heptene
From point of stereochemistry it can also be written as trans-3-heptene as the hydrogens are placed in opposite side of the C=C bond.
Hope this helps...
The compound name is: trans 3-heptene
What is molecular compound?Molecular compounds are inorganic compounds that take the form of discrete molecules.
Looking at the given compound:
1. We need to look for the highest carbon chain, So in this compound the highest carbon chain is of 7 carbon atoms.
2. This compound also has a double bond in between that is present at the third carbon which can be detected by numbering the carbon in a order where the lowest number will come over a double bond.
3. Lastly, we can derive the name for this compound as hept-3-ene or 3-heptene.
4. Also, there is one more thing to notice here which is the position of two hydrogen that are present as substituents since they are placed opposite to each other thus we can name it as trans 3-heptene.
Thus, the compound name is: trans 3-heptene.
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Enter an abbreviated electron configuration for magnesium: Express your answer in complete form, in order of increasing energy. For example, [He]2s22p2 would be entered as [He]2s^22p^2.
Answer:
[Ne]3s²
Explanation:
Mg
1s2 2s2 2p6 3s2 or [Ne]3s²
Abbreviated electronic configuration of magnesium is [Ne]3 s² and in complete form it is 1 s² 2 s² 2 p⁶ 3 s².
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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Consider each of the following molecules in turn: (a) dimethyl ether, (CH3)2O; (b) trimethylamine, (CH3)3N; (c) trimethylboron, (CH3)3B; and (d) carbon dioxide (CO2). Describe the hybridization state of the central atom (i.e., O, N, B, or C) of each molecule, tell what bond angles you would expect at the central atom, and state whether the molecule would have a dipole moment.
Answer:
Consider each of the following molecules in turn: (a) dimethyl ether, (CH3)2O; (b) trimethylamine, (CH3)3N; (c) trimethylboron, (CH3)3B; and (d) carbon dioxide (CO2). Describe the hybridization state of the central atom (i.e., O, N, B, or C) of each molecule, tell what bond angles you would expect at the central atom, and state whether the molecule would have a dipole moment.
2. A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine:2HI (g) H2(g) + I2(g)When the system comes to equilibrium at 425 °C, PHI = 0.794 atm, and PH2 = PI2 = 0.0685 atm. The value of Kp at this temperature is ________.
Answer:
The value of Kp at this temperature is 7.44*10⁻³
Explanation:
Chemical equilibrium is established when there are two opposite reactions that take place simultaneously at the same speed.
For the general chemical equation for a homogeneous gas phase system:
aA + bB ⇔ cC + dD
where a, b, c and d are the stoichiometric coefficients of compounds A, B, C and D, the equilibrium constant Kp is determined by the following expression:
[tex]Kp=\frac{P_{C} ^{c} *P_{D} ^{d} }{P_{A} ^{a} *P_{B} ^{b} }[/tex]
Where Px is the partial pressure of each of the components once equilibrium has been reached and they are expressed in atmospheres. The equilibrium constant Kp depends solely on temperature and is dimensionless.
In the case of the reaction:
2 HI (g) ⇔ H₂ (g) + I₂ (g)
the equilibrium constant Kp is determined by the following expression:
[tex]Kp=\frac{P_{H_{2} } *P_{I_{2} } }{P_{HI} ^{2} }[/tex]
The system comes to equilibrium at 425 °C, and
PHI = 0.794 atmPH2 = 0.0685 atmPI2 = 0.0685 atmReplacing:
[tex]Kp=\frac{0.0685*0.0685}{0.794^{2} }[/tex]
Kp=7.44*10⁻³
The value of Kp at this temperature is 7.44*10⁻³
Use the link Standard Reduction Potentials. Write net equations for the spontaneous redox reactions that occur during the following or none (all lower case) if there is no extensive reaction. Use the lowest possible coefficients. A) Iron metal is dipped into a Ni2+ solution.B) Copper metal is added to hydrochloric acid.C) A silver wire is added to nitric acid (HNO3).D) Magnesium metal is added to waterE) Chromium metal is added to a solution of Mg2+
Answer:
a) Fe(s) + Ni^2+(aq) ----> Fe^2+(aq) + Ni(s)
b) no reaction
c) no reaction
d) 2Mg(s) + 2H2O(l)-----> 2Mg^2+(aq) + O2(g) +4H^+(aq)
e) no reaction
Explanation:
It is important to say here that the ability of a particular chemical specie to displace another chemical specie is dependent on the relative standard reduction potentials of the species involved.
All the reactions stated above are redox reactions. Let us take reaction E as an example. Mg^2+ has a reduction potential of -2.37 V while Cr^3+ has a reduction potential of -0.74V. Since the reduction potential of magnesium is more negative than that of chromium, there is no reaction when a piece of chromium metal is dipped into a solution of Mg^2+.
Similarly, though metals displace hydrogen gas from dilute acids, metals that are less than hydrogen in the reactivity series cannot do that. This explains why there is no reaction when copper and silver are dipped into dilute acid solutions.
Reaction occurs when iron is dipped into a nickel solution because the reduction potential of Fe^2+ is far more negative than that of Ni^2+.
Nitrosyl bromide, NOBr, is formed from NO and Br2.
2 NO(g) + Br2(g) 2 NOBr(g)
Experiments show the reaction is second order in NO and first order in Br2.
How does the reaction rate change if the concentration of Br2 is changed from 0.0022 mol/L to 0.0066 mol/L?
a) the rate will double
b) the rate will remain unchanged
c) the rate will triple
Answer:
C ) The rate will triple
Combustion analysis of 2.400 g of an unknown compound containing carbon, hydrogen, and oxygen produced 4.171 g of CO2and 2.268 g of H2O. What is the empirical formula of the compound
Answer:
[tex]C_3H_8O_2[/tex]
Explanation:
Hello,
In this case, for the given combustion process, we can compute the present moles of carbon atoms by considering that the only product containing carbon is CO2, thus, we have:
[tex]n_C=4.171gCO_2*\frac{1molCO_2}{44gCO_2}*\frac{1molC}{1molCO_2} =0.095molC[/tex]
Next, we compute the moles of hydrogen that is present at the water only as a product:
[tex]n_H=2.268gH_2O*\frac{1molH_2O}{18gH_2O}*\frac{2molH}{1molH_2O} =0.252molH[/tex]
Then, we compute the moles of oxygen by considering the oxygen present in both the CO2 and H2O and the initial sample:
[tex]m_O=2.400g-0.095molC*\frac{12gC}{1molC} -0.252molH*\frac{1gH}{1molH} \\\\m_O=1.008gO\\\\n_O=1.008gO*\frac{1molO}{16gO} =0.063molO[/tex]
Now, we divide the moles of C, H and O by the moles of O since they are lower amount, in order to compute the subscript in the empirical formula:
[tex]C=\frac{0.095}{0.063}=1.5\\ \\H=\frac{0.252}{0.063}=4\\ \\O=\frac{0.063}{0.063}=1[/tex]
But the smallest whole number is:
[tex]C_3H_8O_2[/tex]
Regards.
uppose you are standardizing a sodium hydroxide solution with K H P (molar mass=204.2 g/mol) according to the equation K H P + N a O H ⟶ H 2 O + N a K P You prepare the standard solution from 0.294 g of K H P in 250.0 mL of water. You then require 7.42 mL of N a O H solution to complete the titration. What is the concentration of the N a O H solution?
Answer: The concentration of NaOH solution is 0.194 M
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of KHP = 0.294 g
Molar mass of KHP = 204.22 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of KHP}=\frac{0.294g}{204.22g/mol}=0.00144mol[/tex]
The chemical reaction follows the equation:
[tex]KHC_8H_4O_4(aq.)+NaOH\rightarrow KNaC_8H_4O_4(aq.)+H_2O(l)[/tex]
By Stoichiometry of the reaction:
1 mole of KHP reacts with 1 mole of NaOH.
So, 0.00144 moles of KHP will react with = 0.0144 of KOH.
To calculate the molarity of NaOH, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]
We are given:
Moles of KOH = 0.00144 moles
Volume of solution = 7.42ml = 0.00742L (Conversion factor: 1L = 1000 mL)
Putting values in above equation, we get:
[tex]Molarity=\frac{0.00144mol}{0.00742L}=0.194M[/tex]
Hence, the molarity of NaOH solution is 0.194 M
The concentration of the NaOH solution used in complete titration has been 0.194 M.
The reaction of KHP with NaOH has been the neutralization reaction that results in the formation of salt and water.
The concentration of KHP solution has been:
Molarity = [tex]\rm \dfrac{weight}{Molecular\;weight}\;\times\;\dfrac{1000}{Volume\;(ml)}[/tex]
Molarity of KHP = [tex]\rm \dfrac{0.294}{204.2}\;\times\;\dfrac{1000}{250}[/tex]
Molarity of KHP = 0.0057 M
The concentration of the KHP solution has been 0.0057 M.
For the neutralization reaction in complete titration:
Molarity of acid [tex]\times[/tex] Volume of acid = Molarity of base [tex]\times[/tex] Volume of base
Substituting the values from the question:
0.0057 M [tex]\times[/tex] 250 ml = Molarity of NaOH [tex]\times[/tex] 7.42 ml
1.439 = Molarity of NaOH [tex]\times[/tex] 7.42 ml
Molarity of NaOH = 0.194 M.
The concentration of the NaOH solution used in complete titration has been 0.194 M.
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g The pH of gastric juice in the stomach of a certain individual is 1.50. After a few aspirin tablets have been swallowed, the concentration of acetylsalicylic acid in the stomach is 0.400 M. Calculate the percent ionization of the acid under these conditions.
Answer: After a few aspirin tablets have been swallowed, the concentration of acetylsalicylic acid in the stomach is 0.20 M. Calculate the percent ionization of the acid under these conditions. Therefore, the percent ionization is - X 100% = 3.8%.
How have safety concerns about chemicals changed over time?
A. Government officials rather than scientists decide what chemicals
are dangerous.
B. All nations have agreed to a set of safety standards, so testing
chemicals is no longer necessary.
C. As scientists have learned more about chemicals, they have
become more aware of their dangers.
D. Scientists are no longer as concerned about chemicals because
they are much safer today.
Answer:
C. As scientists have learned more about chemicals, they have become more aware of their dangers
Explanation:
Chemicals are substances with standard compositions, held together by chemical bonds. Chemicals can exist in different phases such as solid, liquid, and gaseous phases. Over time, with a growing understanding of chemicals, their composition, and their reaction methods, scientists now have a better knowledge of the dangers chemicals can pose. To that effect, they have created standard safety measures for those who have to work with these chemicals.
When these guidelines are strictly adhered to, the chances of suffering accidents, burns, and explosions with these chemicals are significantly reduced.
The first solution will be an unbuffered sucrose solution. Calculate the amount of 0.1 M sucrose stock solution and the amount of dH2O needed to prepare 100 mL of unbuffered 20 mM sucrose.
Answer:
20mL of the stock solution and dilute to 100mL
Explanation:
20mM = 0.020M is the concentration of the diluted solution. As you want to prepare this solution from a 0.1M solution, dilution factor is:
0.1M / 0.020M = 5
That means you need to dilute the stock solution 5 times to obtain the 20mM sucrose solution.
As you want to prepare 100mL, you need to add:
100mL / 5 =
20mL of the stock solution and dilute to 100mLPre-Lab Study Questions / 9
1. Where are the valence electrons in an atom?
valen
2. How are positive and negative ions fomed?
3. Why are electrons shared in molecular compounds?
Answer:
See detailed answer with explanation below.
Explanation:
Valence electrons are electrons found on the outermost shell of an atom. They are the electrons in an atom that participate in chemical combination. Recall that the outermost shell of an atom is also referred to as its valence shell. Let us consider an example; if we look at the atom, sodium-11, its electronic configuration is 2,8,1. The last one electron is the valence electron of sodium which is found in its outermost or valence shell.
Positive ions are formed when electrons are lost from the valence shell of an atom. For instance, if the outermost electron in sodium is lost, we now form the sodium ion Na^+ which is a positive ion. Positive ions possess less number of electrons compared to their corresponding atoms.
Negative ions are formed when one or more electrons is added to the valence shell of an atom. A negative ion possesses more electrons than its corresponding atom. For example, chlorine(Cl) contains 17 electrons but the chloride ion (Cl^-) contains 18 electrons.
In molecular compounds, a bond is formed when two electrons are shared between the bonding atoms. Each bonding atom may contribute one of the shared electrons (ordinary covalent bond) or one of the bonding atoms may provide the both shared electrons (coordinate covalent bond). The shared pair may be located at an equidistant position to the nucleus of both atoms. Similarly, the electron may be drawn closer to the nucleus of one atom than the other (polar covalent bond) depending on the electro negativity of the two bonding atoms.
The electrons are shared in order to complete the octet of each atom by so doing, the both bonding atoms now obey the octet rule. For example, two chlorine atoms may come together to form a covalent bond in which each chlorine atom has an octet of electrons on its outermost shell.
(03.01 LC
Which of the following is not present in an atom? (1 point)
Answer:
Protons, Neutrons, and Electrons are all in atoms so the one not present would be the Element since Elements are made of atoms.
Explanation:
Consider the heating curve for water. A graph of the heating curve for water has time in minutes on the horizontal axis and Temperature in degrees Celsius on the vertical axis. A line runs through the following points: 0 minutes, negative 20 degrees; 0.5 minutes, 0 degrees; 2 minutes, 0 degrees; 4 minutes, 100 degrees; 8 minutes, 100 degrees; 9.5 minutes, 160 degrees. At what temperature does the solid start melting? –20°C 0°C 20°C 80°C
Answer:
0°C.
Explanation:
Hello,
In this case, given the heating curve of water on the attached document, we can notice that at 0 °C the solid starts melting, which means that the melting point is reached. Melting point is known as a physical change whereby a solid changes to liquid by the addition of heat as it allows the molecules to separate to each other.
Best regards.
Answer:
0 degrees celcius
Explanation:
I took the test
On the reaction below, label the BSA, BSB, CA, and CB. CH3COOH + H2O → CH3COO– + H3O+
Answer:
Acid(BSA) = CH₃COOH
Base (BSB) = H₂O
Conjugate base (CB) = CH₃COO⁻
Conjugate acid (CA) = H₃O⁺
Explanation:
Equation of reaction;
CH₃COOH + H₂O → CH₃COO⁻ + H₃O⁺
Hello,
From my understanding of the question, we are required to identify the
1) Acid
2) Base
3) conjugate acid
4) conjugate base in the reaction
Acid (BSA) = CH₃COOH
Base (BSB) = H₂O
CA = conjugate acid = H₃O⁺
CB = conjugate base = CH₃COO⁻
Rank the following transitions in a hydrogen atom in order of increasing wavelength of electromagnetic radiation that could produce them. Answer this question without doing any calculations. Explain the order.
n=2 to n=4
n=6 to n=8
n=10 to n=12
n=14 to n=16
Answer:
n=2 to n=4 < n=6 to n=8 < n=10 to n=12 < n=14 to n=16
Explanation:
According to Neils Bohr, electrons in an atom are found in specified energy levels. Transitions are possible from one energy level to another when the electron receives sufficient energy usually in the form of a photon of electromagnetic radiation of appropriate frequency and wavelength. The energy of this photon corresponds to the energy difference between the two energy levels. Thus the higher the energy difference between energy levels, the greater the energy of the photon required to cause the transition and the shorter the wavelength of the photon.
High energy photons have a very short wavelength. It should be noted that as n increases, the energy of successive energy levels decreases and transitions between them now occurs at longer wavelengths. Hence, the highest energy and shortest wavelength of photons are required for transition involving lower values of n because such electrons are closer to the nucleus and are more tightly bound to it than electrons found at a greater distance from the nucleus.
Hence transition involving electrons at higher energy levels occur at a longer wavelength compared to transition involving electrons closer to the nucleus. This is the basis for the arrangement of wavelengths required to effect the various electronic transitions shown in the answer.
a man a man weighing 800 and climbs up a flight of stairs to a height of 15 m in 12 seconds what is the man's average power output
Answer:
1 kW
Explanation:
We assume the man's weight is measured in newtons. Then the power expended is ...
(800 N)(15 m)/(12 s) = (12000 N·m)/(12 s) = 1000 N·m/s = 1000 W
The man's average power output is 1 kilowatt.
Calculate ΔG (in kJ) for the following reaction at 1.0 atm for C2H6, 0.5 atm for O2, and 2.0 atm for CO2, and 25 oC: C2H6 (g) + O2 (g) ---> CO2 (g) + H2O (l) (unbalanced) ΔGfo C2H6 (g) = - 32.89 kJ/mol; ΔGfo CO2 (g) = - 394.4 kJ/mol; ΔGfo H2O (l) = - 237.13 kJ/mol
Answer:
Explanation:
Calculate ΔG (in kJ) for the following reaction at 1.0 atm for C2H6,
0.5 atm for O2, and
2.0 atm for CO2, and
25 oC:
C2H6 (g) + O2 (g) ---> CO2 (g) + H2O (l) (unbalanced)
ΔGfo C2H6 (g) = - 32.89 kJ/mol;
ΔGfo CO2 (g) = - 394.4 kJ/mol;
ΔGfo H2O (l) = - 237.13 kJ/mol
The balance equation of this reaction is
[tex]2C_2H_6 (g) + 7O_2 (g) ---> 4CO_2 (g) + 6H_2O (l)[/tex]
[tex]\Delta G_{rxn}=\sum G^o_f(product)-\sum G^o_f(reactant)[/tex]
[tex]=4G^o_f(CO_2)+6G^o_f(H_2O)-7G^o_f(O_2)-2G^o_f(C_2H_6)\\\\[/tex]
[tex][4(-394.4)+6(-237.13)-7(0)-2(-32.89)]kJ/mol\\\\=-1577.6-1422.78+65.78\\\\=-3000.38+65.78\\\\=-2934.6kJ/mol[/tex]
why boric acid considered as a weak acid
Boric acid is not what is known as a protonic acid meaning it is unable to release the H+ ions by itself. However, it can act as a traditional Lewis Acid so it is considered a weak acid.
Answer:
Boric acid is not able to release H⊕ ion on its own. It receives ӨOH ion from water molecule to complete its octet and in turn releases H⊕ ions.
It has the chemical formula H3BO3 (sometimes written B(OH)3), and exists in the form of colorless crystals or a white powder that dissolves in water. When occurring as a mineral, it is called sassolite
credit : wikipedia
In the laboratory, a general chemistry student measured the pH of a 0.592 M aqueous solution of triethanolamine, C6H15O3N to be 10.781. Use the information she obtained to determine the Kb for this base.
Kb(experiment) =_______
Answer:
[tex]Kb=6.16x10^{-7}[/tex]
Explanation:
Hello,
In this case, given the pH of the base, we can compute the pOH as shown below:
[tex]pOH=14-pH=14-10.781=3.219[/tex]
Next, we compute the concentration of the hydroxyl ions when the triethanolamine is dissociated:
[tex]pOH=-log([OH^-])[/tex]
[tex][OH^-]=10^{-pOH}=10^{-3.219}=6.04x10^{-4}M[/tex]
Then, by writing the equilibrium expression for the dissociation of triethanolamine we have:
[tex]Kb=\frac{[OH^-][C6H14O2N^+]}{[C6H15O3N ]}[/tex]
That is suitable for the direct computation of Kb, knowing that based on the ICE procedure, [tex]x[/tex] equals the concentration of hydroxyl ions that was previously, computed, therefore, we have:
[tex]Kb=\frac{6.04x10^{-4}M*6.04x10^{-4}M}{0.592M-6.04x10^{-4}M}\\ \\Kb=6.16x10^{-7}[/tex]
Regards.
In the first step of glycolysis, the given two reactions are coupled. reaction 1:reaction 2:glucose+Pi⟶glucose-6-phosphate+H2OATP+H2O⟶ADP+PiΔG=+13.8 kJ/molΔG=−30.5 kJ/mol Answer the four questions about the first step of glycolysis. Is reaction 1 spontaneous or nonspontaneous?
Answer: Reaction 1 is non spontaneous.
Explanation:
According to Gibb's equation:
[tex]\Delta G=\Delta H-T\Delta S[/tex]
[tex]\Delta G[/tex] = Gibbs free energy
[tex]\Delta H[/tex] = enthalpy change
[tex]\Delta S[/tex] = entropy change
T = temperature in Kelvin
When [tex]\Delta G[/tex] = +ve, reaction is non spontaneous
[tex]\Delta G[/tex]= -ve, reaction is spontaneous
[tex]\Delta G[/tex]= 0, reaction is in equilibrium
For the given reaction 1: [tex]glucose+Pi\rightarrow glucose-6-phosphate+H_2O[/tex] [tex]\Delta G=+13.8kJ/mol[/tex]
As for the reaction 1 , the value of Gibbs free energy is positive and thus the reaction 1 is non spontaneous.
QUESTION 11
Which of the following compounds has the highest boiling poid?
O CH3CH2CH2COOH
O CH3OCH2CH2CH3
O CH3CH2CH2OH
O CH3CH2CH2CHO
Answer:
CH3CH2CH2COOH
Explanation:
Both carboxylic acids and alcohols posses hydrogen bonding. The difference between the two lies in the strength of the hydrogen bonding and the structure of the molecules.
Alcohols predominantly form linear hydrogen bonds in which the dipole of the -OH group of one molecule interacts with that of another molecule. This gives a linear arrangement of hydrogen bonded intermolecular interactions which significantly impacts the boiling point of alcohols.
However, the carboxylic acids posses the carbonyl (C=O) which is more polar and interacts more effectively with the -OH bond to form dimmer species. These dimmers have a much higher boiling point than the corresponding alcohols due to stronger hydrogen bonds. Hence CH3CH2CH2COOH has a greater boiling point than CH3CH2CH2OH.
The other compounds in the options do not posses hydrogen bonds hence they will have much lower boiling points.
A loud classroom demonstration involves igniting a hydrogen filled balloon. The hydrogen within the balloon reacts explosively with oxygen in the air to form water. If the balloon is filled with a mixture of hydrogen and oxygen, the explosion is even louder than if the balloon is filled only with hydrogen-the intensity of the explosion depends on the relative amounts of oxygen and hydrogen gas within the balloon. Look at the molecular views representing different amounts of hydrogen and oxygen gas in four different balloons of equal size. Based on the balanced chemical equation (you will have to write one), which balloon will make the loudest explosion
Hey there!
balanced chemical reaction:
2 H₂ (g) + 1 O₂ ( g ) ----------> 2 H₂O ( g )
Reagents :
H = 2 * 2 = 4
O = 1 * 2 = 2
----------------------
total = 4 + 2 => 6
Products:
H = 2 * 2 = 4
O = 2 * 1 = 2
___________
total = 4 + 2 => 6
Hope this helps
Which metal will spontaneously react with Zn2+
(aq),
but will not spontaneously react with Mg2+
(aq)
according to the activity series
The options of the question is not given so the options are;
(1) Mn(s)
(2) Cu(s)
(3) Ni(s)
(4) Ba(s)
Answer: Mn(s)
Explanation:
The spontaneous reaction depends on the Eo value. The positive Eo value are spontaneous and the negative Eo values are not spontaneous.
so, here the Eo values are:
Eo Zn2+/Zn = -0.763v
Eo Mg2+/Mg = 2.37v
Eo Mn2+/Mn = -1.18v
Therefore, Eo cell (with Zn as one of the half-cell) = Eo Zn2+/Zn - Eo Mn2+/Mn
= -0.763 - (-1.18)
= 0.417v
Whereas, Eo cell (with Mg as one of the half-cell) = Eo Mg2+/Zn - Eo Mn2+/Mn
= -2.37 - (-1.18) = -1.19v
Thus, Mn(s) metal will spontaneously react because it has a positive Eo value and Zn2+(aq), but will not spontaneously react with Mg2+(aq) because it has negative Eo value.