Answer:
Chemical change
Explanation:
The rusting of iron/a nail is a chemical change
Iron (Fe) and Oxygen (O) combine to create the compound Iron Oxide (Fe2O3), which is rust.
A chemist heats 34.10 g of nickel to 77.17 °C, then places the metal sample in the cup of water shown in the interactive.
Calculate the final temperature of the water. The specific heat of nickel is 0.444 J/g °C and the specific heat of water is
4.184 J/g °C.
Answer:
[tex]T_{eq}=27.97\°C[/tex]
Explanation:
Hello.
In this case, for equilibrium temperature problems, it is said that the heat balance allows us to notice how the hot substance heats up the cold substance until they reach the equilibrium temperature which is a temperature that remains constant upon time. Thus, since here the hot substance is the nickel and water gains that released heat by the nickel we can write:
[tex]Q_{Zn}=-Q_{water}[/tex]
Which can be written in terms of temperatures, masses and specific heats:
[tex]m_{Zn}C_{Zn}(T_{eq}-T_{Zn})=-m_{water}C_{water}(T_{eq}-T_{water})[/tex]
Thus, solving for the equilibrium temperature we write:
[tex]T_{eq}=\frac{m_{Zn}C_{Zn}T_{Zn}+m_{water}C_{water}T_{water}}{m_{Zn}C_{Zn}+m_{water}C_{water}}[/tex]
Now, plugging in the known data, considering the mass of water 64.00-4.00=60.00 g and its initial temperature, 25.00°C, we obtain:
[tex]T_{eq}=\frac{34.10g*0.444\frac{J}{g\°C}* 77.17\°C+60.0g*4.184\frac{J}{g\°C}*25.00\°C}{34.10g*0.444\frac{J}{g\°C}+60.0g*4.184\frac{J}{g\°C}}\\\\T_{eq}=27.97\°C[/tex]
Best regards!
The final temperature of water is required.
The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].
T = Equilibrium temperature
[tex]T_n[/tex] = Temperature of nickel = [tex](77.17^{\circ}\text{C}+273.15)\ \text{K}[/tex]
[tex]T_w[/tex] = Temperature of water = [tex](25^{\circ}\text{C}+273.15)\ \text{K}[/tex]
[tex]c_n[/tex] = Specific heat of nickel = [tex]0.444\ \text{J/g}^{\circ}\text{C}[/tex]
[tex]c_w[/tex] = Specific heat of water = [tex]4.184\ \text{J/g}^{\circ}\text{C}[/tex]
[tex]m_n[/tex] = Mass of nickel = 34.1 g
[tex]m_w[/tex] = Mass of water = 60 g
The heat balance of the system is given by
[tex]m_wc_w(T-T_w)=m_nc_n(T_n-T)\\\Rightarrow m_wc_wT-m_wc_wT_w=m_nc_nT_n-m_nc_nT\\\Rightarrow T=\dfrac{m_nc_nT_n+m_wc_wT_w}{m_wc_w+m_nc_n}\\\Rightarrow T=\dfrac{34.1\times 0.444\times 350.32+60\times 4.184\times 298.15}{60\times 4.184+34.1\times 0.444}\\\Rightarrow T=301.12\ \text{K}=301.12-273.15\\\Rightarrow T=27.97^{\circ}\text{C}[/tex]
The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].
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how many moles of hydrogen are needed to produce 8 moles of methane CH4? C + H2-> CH4
Answer:
20 mol H₂
General Formulas and Concepts:
Chem
StoichiometryExplanation:
Step 1: Define
RxN: C + H₂ → CH₄
8 moles CH₄
Step 2: Balance RxN
C + 2H₂ → CH₄
Step 3: Stoichiometry
[tex]8 \ mol \ CH_4(\frac{2 \ mol \ H_2}{1 \ mol \ CH_4} )[/tex] = 16 mol H₂
Step 4: Check
We are given 1 sig fig. Follow sig fig rules.
16 mol H₂ ≈ 20 mol H₂
Consider a three-dimensional model of methane as seen here in two dimensions. If we use VSEPR theory to describe the geometry of a methane molecule we say its shape is. A) Linear. B) Tetrahedral. C)Trigonal Planar. D)Trigonal Bipyramidal
Answer:B
Explanation:
Tetrahedral I took the test
Answer:
B is the answer'
Explanation:
A gas-forming reaction produces 1.95 m3 of gas against a constant pressure of 196.0 kPa. Calculate the work done by the gas in joules.
Answer:
Work done W = -382,206 J (Approx)
Explanation:
We know that;
1 atm = 101.32 kPa
1 L-atm = 101.325 J
1 m³ = 1,000 L
Computation:
Work done W = -P∆V
Pressure = 196 kPa × (1 / 101.32 kPa)
Pressure = 1.9344 atm
∆V = 1.95 × (1000 L) = 1,950 L
So,
W = -(1.9344 atm) × (1,950 L)
W = -3772.0 L-atm
Work done W = -3772.0 L-atm × (101.325 J / 1 L.atm)
Work done W = -382,206 J (Approx)
The work done by the gas in Joules is equal to 3,763.5 Joules.
Given the following data:
Pressure = 196.0 kPa. Volume = 1.95 [tex]m^3[/tex]Conversion:
1 atm = 101.325
X atm = 196.0 kPa
X = [tex]\frac{196.0}{101.325} = 1.93\; atm[/tex]
Conversion:
1 [tex]m^3[/tex] = 1000 Liter
1.95 [tex]m^3[/tex] = 1950 Liter
To calculate the work done by the gas in Joules:
Mathematically, the work energy by a system is given by the formula:
[tex]Work = P \delta V[/tex]
Where:
P is the pressure. V is the volume.
Substituting the parameters into the formula, we have
[tex]Work\;energy = 1.93 \times 1950[/tex]
Work energy = 3,763.5 Joules.
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Select the sentences in the paragraph that explain only the dark lines that are produced in the absorption spectra. Select all that apply.
A light is shown through a cold, dilute gas. Over time, excited atoms revert to their original lower energy state. Photons emitted travel in different directions that the original photon. Gaps are produced in the light spectra that correspond to wavelengths of absorbed photons. Dark lines in an absorption spectrum of light can be seen when the gas lies between the light source and observer.
Answer:
Gaps are produced in the light spectra that correspond to wavelengths of absorbed photons.
Explanation:
When electrons in atoms absorb energy, they move from a lower energy level to a higher energy level. With time, they revert to the their original energy state emitting a photon of light of appropriate wavelength.
The absorbed photons do not show up in the spectrum. They appear as dark lines in the spectrum. Hence, the absorption spectrum is the exact inverse of the emission spectrum. The dark lines in the spectrum indicates that the colors that ought to occupied those points there have been absorbed.
According to Graham’s law, the rate of effusion of a gas is inversely proportional to
A.
the pressure of the gas.
B.
the kinetic energy of the particles.
C.
the square root of the mass of the particles.
D.
the square root of the diffusion of the gas in another gas.
C. the square root of the mass of the particles.
Further explanationGraham's law: the rate of effusion of a gas is inversely proportional to the square root of its molar masses or
the effusion rates of two gases = the square root of the inverse of their molar masses:
[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]
or
[tex]\rm M_1\times r_1^2=M_2\times r_2^2[/tex]
From this equation shows that the greater the mass of the gas, the smaller the effusion rate of the gas and vice versa, the smaller the mass of the gas, the greater the effusion velocity.
So if both gases are at the same temperature and pressure, the above formula can apply
Bonds are broken in an____
reaction.
a). Endergonic
b). Exergonic
Answer:
Reactions where chemical bonds are broken, releasing the energy in those bonds, are often exergonic reactions.
Explanation:
Reactions where chemical bonds are broken, releasing the energy in those bonds, are often exergonic reactions. These reactions where chemicals are broken down are called “catabolism” – the destructive part of metabolism. By contrast, reactions where chemical bonds are formed are often endergonic.
Select True or False: A mixture made from 10 mL of 1 M HCl and 20 mL of 1 M CH3COONa would be classified as a buffer solution.
Answer:
True.
Explanation:
There are three ways to make a buffer.
a. Generating a solution of a weak acid and its conjugate base.
b. Adding to a solution of a weak acid a certain quantity of
strong base, so that the acid remains in excess.
c. adding a limited amount to a conjugate base solution
of strong acid so that the base remains in excess.
We are in c, in this situation.
How do you calculate, pH? We apply Henderson Hasselbach.
pH = pka + log (mmoles base - mmoles acid)/ mmoles acid
pH = pKa + log ((20 ml . 1 M - 1 ml . 10M) / 10 mmoles
pH = 4.76 + log 1 → 4.76 ⇒ pH = pKa
. Calculate the entropy change associated with the isothermal compression of 0.720 mol of an ideal gas from 24.32 L to 3.90 L.
Answer:
[tex]$\Delta S = -10.95 \ \frac{J}{K}$[/tex]
Explanation:
Given :
Number of mole, n = 0.720 mol
Initial volume, [tex]$V_1$[/tex] = 24. 32 L
Final volume, [tex]$V_2$[/tex] = 3.90 L
We know entropy change,
[tex]$\Delta S = c_V\ln \left(\frac{T_2}{T_1}\right) + n R \ln \left(\frac{V_2}{V_1}\right)$[/tex]
For isothermal compression temperature constant,
[tex]$\Delta S = n R \ln \left(\frac{V_2}{V_1}\right)$[/tex]
[tex]$\Delta S = 0.720 \times 8.314 \times \ln \left(\frac{3.90}{24.32}\right)$[/tex]
[tex]$\Delta S = -10.95 \ JK^{-1}$[/tex]
[tex]$\Delta S = -10.95 \ \frac{J}{K}$[/tex]
the molar ratio of cucl2 to Al should be
Answer:
1) The chemical equation is:
Al + CuCl2 ---> Cu + AlCl3
2) You have to balance the equation to state the coefficients:
2Al + 3CuCl2 ---> 3Cu + 2Al Cl3
3) Now the coefficients tell you the molar ratios.
2 mol Al : 3 mol CuCl2 : 3 mol Cu : 2 mol AlCl3
4) The molar ratio of CuCl2 to Al is:
3 mol Cu Cl2 / 2 mol Al = 3/2 = 1.5
Explanation:
Give two everyday examples of the thermal energy of a substance being decreased
Answer:
An example of the thermal energy of a substance being decreased is with our food. With the thermal energy of food being decreased it is easier for foods to be eaten comfortably without any damage to the tongue or alimentary canal.
Another good example is in the handling of hot objects in the home. Thermal energy decrease in objects such as iron, pots etc helps to prevent serious burns and injuries.
Answer:
Water turning into ice
juice frozen to make popsicles
Explanation:
When something goes from liquid to a solid, that is a process called freezing. When a object loses thermal energy the particles move slower forming a solid.
Na₂S
Naming ionic compound
Answer:
Sodium Sulfide
Explanation:
I looked it up
A 0.700 g unknown mixture with CaCl2 reacts with aqueous sodium phosphate to give 0.425 g Ca3(PO4)2. Show calculation for the percentage CaCl2?
The percentage CaCl₂ : 65.14%
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
3CaCl₂+2Na₃PO₄⇒Ca₃(PO₄)₂ + 6NaCl
mol Ca₃(PO₄)₂(MW=310.18 g/mol) :
[tex]\tt \dfrac{0.425}{310.18}=0.00137[/tex]
mol ratio CaCl₂ : Ca₃(PO₄)₂ = 3 : 1, so mol CaCl₂ :
[tex]\tt \dfrac{3}{1}\times 0.00137=0.00411[/tex]
mass CaCl₂ (MW=110.98 g/mol) :
[tex]\tt 0.00411\times 110.98=0.456~g[/tex]
The percentage CaCl₂ :
[tex]\tt \%CaCl_2~in~mixture=\dfrac{0.456}{0.7}\times 100\%=65.14\%[/tex]
de, it
this is a
your
Sample Response: This is a chemical change
because new substances are formed with different
properties and identities.
What did you include in your response? Check all that
apply
rmed with
This is a chemical change.
New substances are formed.
The properties and identities of the original
substances are changed.
If u click on all of them it gives u an A+ and doesn’t even read what u wrote. So u never really have to try hard on the writing parts just tell them u included them all
Answer:An image will not be formed.
Rays do not converge to or diverge from a common point.
/select all that apply
Explanation:
Atom a and atom b have the same number of protons and neutrons but they do not have the same number of electrons. What statement describes the atoms
The given question is incomplete. The complete question is:
Atom a and atom b have the same number of protons and neutrons but they do not have the same number of electrons. What statement describes the atoms?
The atoms have the same chemical symbol.
The atoms have the same charge.
The atoms have different atomic numbers.
The atoms have different atomic masses.
Answer: The atoms have the same chemical symbol.
Explanation:
Atomic number is equal to the number of protons for any neutral or charged specie and is specific to a particular element. Thus two elements having same atomic number will have same chemical symbols.
Mass number is the sum of number of protons and the number of neutrons.
As atoms a nd b have same protons and neutrons , they will have same atomic number and same mass number. But as the number of electrons are different , the charge on them will be different.
Thus the correct statement is the atoms have the same chemical symbol.
Answer:
They have the same chemical symbol
Explanation:
(2 points) How many grams of K2SO4 are present in 25.0 mL of 7.00 % (m/v) solution?
Show your work. No work = no credit.
Mass of K₂SO₄ : 1.75 g
Further explanationThe concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.
volume of solution = 25 ml
% (m/v)=7%
mass of K₂SO₄ :
[tex]\tt \%m/v=\dfrac{mass~of~solute}{volume~of~solution}\times 100\%\\\\7\%=\dfrac{mass~K_SO_4}{25}\times 100\%\\\\mass~K_2SO_4=7\times 25\div 100=1.75~g[/tex]
A gas with a volume of 525 mL at a temperature of -25°C is heated to 175°C.
What is the new volume, in milliliters, of the gas if pressure and number of moles
are held constant?
Answer:
Volume V2 = 948.13 ml
Explanation:
Given:
Volume V1 = 525 ml
Temperature T1 = -25°C + 273.15
Volume V2 = ?
Temperature T1 = 175°C + 273.15
Computation:
V1 / T1 = V2 / T2
525 / [-25°C + 273.15] = V2 / [175°C + 273.15]
Volume V2 = 948.13 ml
The new volume, in milliliters, of the gas is 948 L
From the question,
We are to determine the new volume of the gas.
From Charles' law which states that the volume of a fixed mass of gas is directly proportional to the temperature (in Kelvin) provided that the pressure remains constant.
That is,
V ∝ T
Then,
V = kT
Therefore, we can write that
[tex]\frac{V_{1} }{T_{1}} = \frac{V_{2}}{T_{2}}[/tex]
Where [tex]V_{1}[/tex] is the initial volume
[tex]T_{1}[/tex] is the initial temperature
[tex]V_{2}[/tex] is the final volume
and [tex]T_{2}[/tex] is the final temperature
From the given information,
[tex]V_{1} = 525 \ mL[/tex]
[tex]T_{1} = -25 ^{\circ}C = -25 + 273.15 \ K = 248.15 \ K[/tex]
[tex]T_{2} = 175 ^{\circ} C = 175 +273.15 \ K =448.15 \ K[/tex]
Putting the values into the formula, we get
[tex]\frac{525}{248.15} = \frac{V_{2} }{448.15}[/tex]
∴ [tex]V_{2} = \frac{525 \times 448.15}{248.15}[/tex]
[tex]V_{2} = \frac{235278.75}{248.15}[/tex]
[tex]V_{2} = 948.13 \ L[/tex]
V₂ ≅ 948 L
Hence, the new volume, in milliliters, of the gas is 948 L
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. A 20.0 % by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?
The molar mass of phosphoric acid (H3PO4) is 97.99 g.
Answer:
2.273M
Explanation:
What is the definition of molarity.
M = mols/L. So that's what we need to determine.
How much does a L weigh? That's
1.114 g/mL x 1000 mL = 1114 grams. Simple enough, eh?
How much of that 1114 g is H3PO4. It says it is 20% by mass, therefore, 1114 g x 0.20 = 222.8 g.
How many mols are there in 222.8 g H3PO4? That's mools = grams/molar mass = 222.8/98 = 2.273 mols.
The definition of M is what? M = mols/L. And you have 2.273 mol/L; that must be the molarity.
The formula is
density g/mL x 1000 mL x mass% x (1/molar mass) = M
1.114 x 1000 x 0.20 x (1/98) = 2.273 M.
Choose all the answers that apply.
Which of the following statements are true?
OThe space between neurons is called a synapse.
OThe nucleus of a neuron is located in the cell body.
O Practice can increase the speed of neuron signal transfer.
0Axons carry messages toward the cell body.
o Electrical impulses in neurons go two ways.
Answer:
I think this the right answer maybe, the space between neurons is called a synapse. The nucleus of a neuron is located in the cell body. Axons carry messages toward the cell body. These are the true ones I think.
Explanation:
Answer:
1,2, and 4
Explanation:
10. How many molecules of NH, could you make with 15 molecules of H2 and 4 molecules of Nz? What is
your limiting reactant? Which reactant is in excess?
15 molecules H2X
molecules NH
molecules H2
4 molecules N2 x
molecules NH3
molecules N2
Amount of NH, made:
Limiting reactant:
Excess reactant:
Limiting reactant : N₂
Excess reactant : H₂
amount of NH₃ : 8 molecules
Further explanationThe reaction equation is the chemical formula of reagents and product substances
A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
[tex]\tt N_2+3H_2\rightarrow 2NH_3[/tex]
limiting reactant = smaller mol ratio
N₂[tex]\tt \dfrac{4}{1}=4[/tex]
H₂[tex]\tt \dfrac{15}{3}=5[/tex]
limiting reactant ⇒ N₂
The number of reacted H₂ molecules :
[tex]\tt \dfrac{3}{1}\times 4=12[/tex]
The remaining H₂ after the reaction :
[tex]\tt 15-12=3~molecules[/tex]
Amount of NH₃ :
[tex]\tt \dfrac{2}{1}\times 4=8~molecules[/tex]
Use the periodic table to match each of the following element symbols to its name, atomic mass, or atomic number. (3 points)
1.
Se
2.
S
3.
Sn
a.
Tin
b.
78.971 u (atomic mass)
c.
16 (atomic number)
Answer:
Tin I thunk
Explanation:
I think
Answer:
sn = tin
se = 78.971 u (atomic mass)
s = 16 (atomic number)
2. Calculate the new molanty of a solution formed when 20 ml of water is added to 100 ml of
0.2M NaOH
Answer:
New molarity = M₂ = 0.167 M
Explanation:
Given data:
New molarity = M₂ = ?
Final volume = V₂ = 100mL + 20 mL = 120 mL
Initial volume =M₁ = 100 mL
Initial molarity =V₁ = 0.2 M
Solution:
M₁V₁ = M₂V₂
0.2 M × 100 mL = M₂ × 100 mL
M₂ = 0.2 M × 100 mL/120 mL
M₂ = 20 M.mL/120 mL
M₂ = 0.167 M
How many moles of H20 are required to react completely with 7.30 moles of NO2?
3NO2(g) + H200 +
NO(g) + 2HNO3(aq) A
1.86 mol
2.19 mol
2.43 mol
O 6.12 mol
O 7.30 mol
Answer:
2.43 moles of water are require.
Explanation:
Number of moles of water required = ?
Number of moles of NO₂ available = 7.30 mol
Solution:
Chemical equation:
3NO₂ + H₂O → NO + 2HNO₃
now we will compare the moles of NO₂ with H₂O.
NO₂ : H₂O
3 : 1
7.30 : 1/3×7.30 = 2.43 mol
1. How many moles of water molecules are there in 39 grams of Chlorine?
2. How many molecules are there in 39 grams of Gold?
Answer:
1. There is no moles of water in 39g of chlorine.
2. 1.19x10²³ molecules of Au.
Explanation:
First, we need to remember that molar mass of a compound represents the mass of 1 mole (6.022x10²³ molecules) of molecules.
Molar mass of Chlorine, Cl₂ is 70.9g/mol
Molar mass of gold, Au, is 197g/mol
1. Moles of 39g of Cl₂ are:
39g Cl₂ * (1mol / 70.9g) = 0.55 moles moles of chlorine
But there is no moles of water in 39g of chlorine.
2. First, moles of Au are:
39g Au * (1mol / 197g) = 0.198 moles Au.
Molecules are:
0.198 moles Au * (6.022x10²³ molecules / 1 mol) =
1.19x10²³ molecules of AuAnswer the question plssss
Answer: warmer because its an exothermic reaction.
Explanation: the passage states as the products form thermal energy is absorbed thermal means heat also carbon dioxide creates bubbles
What is meant by the "frequency of light"? What symbol is used for it, and what is the SI unit for frequency?
Answer: Units. The SI derived unit of frequency is the hertz (Hz), named after the German physicist Heinrich Hertz. One hertz means that an event repeats once per second.
The frequency is the number of waves that pass a point in space during any time interval, usually one second. We measure it in units of cycles (waves) per second, or hertz. The frequency of visible light is referred to as color, and ranges from 430 trillion hertz, seen as red, to 750 trillion hertz, seen as violet.
Frequency of an electromagnetic wave is the number of wave cycles per unit time. The SI unit of frequency is Hertz or Hz. Frequency is represented by the symbol v called neu.
What is electromagnetic wave?Waves are propagation or transfer of energy through air or vacuum. An electromagnetic wave is associated with a combined electric field and magnetic field.
Waves are associated with characteristic frequency and wavelength. Wavelength of a wave is the distance between its two consecutive crests or troughs.
Frequency of a wave is the number of wave cycles per unit time. Its is expressed in the unit of Hertz or Hz. Frequency and wavelength are in inverse relation. The shortest waves have greater energy and greater frequency.
Frequency is inverse of time of propagation. So that it can also be used in s⁻¹ which is equal to one hertz.
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What is the pH of a solution in which [H 3O +] = 3.8 × 10 -8 M?
Answer:
The answer is 7.42Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ { H_3O}^{+}][/tex]
From the question we have
[tex]pH = - log(3.8 \times {10}^{ - 8} ) \\ = 7.420216...[/tex]
We have the final answer as
7.42Hope this helps you
Write a balanced molecular equation (photo)
Answer:
Ba + 2HCl = BaCl₂ + H₂
Explanation:
The equation for Magnesiunm's reaction with hydrochloric acid is
Mg + 2HCl = MgCl₂ + H₂
So, just replace magnesium in the equation above and you get the equation for barium's reaction with hydrochloric acid.
which part of earth absorbs the most sunlight?
A oceans
b soil
c atmosphere
d rivers and lakes
Answer:
atmosphere
Explanation:
The atmosphere absorbs the most in light because the atmosphere surrounds our planet
Answer:
c
Explanation:
It can be seen that the three methyl groups in camphor and isoborneol show up as separate peaks, whereas those in borneol overlap to where they almost appear as a single peak. Based on your knowledge of chemical shift factors, explain why this is so?
Answer:
isoborneol and camphor both have methyl groups that have different shielding zones with -OH and -C=O groups respectively.
Explanation:
Using the knowledge of chemical shift we can see that out of the three methyl groups in isoborneol, there are two methyl groups that are not influenced by the chemical Influence of the -OH functional group while one of the methyl groups is influenced by the -OH functional group.
For Camphor, two out of the three methyl groups are in shielding zones of the Carbonyl group, -C=O. While the last of the three methyl groups is out of the shielding zones of Carbonyl group, -C=O.