Question 1

An unknown gas has a root mean square velocity of 332 m s^-1 at 313 K.Identify the unknown gas. A)Kr B)O₂ C)Ar D)F₂ E)Cl₂

Accepted Answer

The answer of An unknown gas has a root mean...

Question 2

What is the temperature if krypton has a root mean square velocity of 348 m $s ^ { - 1 }$ ?
A)800°C
B)791°C
C)134°C
D)604°C
E)596°C

Accepted Answer

The root mean square velocity (rms) of atoms is given by the equation rms velocity = √(3kT/m), where k is the Boltzmann constant, T is the temperature in Kelvin and m is the mass of the atom. 
Rearranging this equation for T, we get T = (m * rms velocity^2)/(3k). 
For krypton, m is approximately equal to 83.80 u (atomic mass units) or 1.40 × 10^-25 kg. 
Substituting this into the equation and converting the velocity to SI units, we get T = (1.40 × 10^-25 kg * (348 m/s)^2)/(3 * 1.38 × 10^-23 J/K) ≈ 134°C. Hence, the correct answer is option C.

Question 3

Identify the gas particle that travels the slowest. A)H₂ B)O₂ C)Ne D)N₂ E)CO

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Question 4

How many millilitres of ozone gas at 25.0 °C and 1.00 bar are needed to react with 45.00 mL of a 0.100 mol L^-1 aqueous solution of KI according to the chemical equation shown below? O₃(g)+ 2I^-(aq)+ H₂O(l)→ O₂(g)+ I₂(s)+ 2OH^-(aq) A)54.8 mL B)110 mL C)165 mL D)220 mL

Accepted Answer

From the balanced chemical equation, we can see that one mole of Ozone reacts with two moles of KI. Therefore, the number of moles of KI present in 45.00 mL of 0.100 mol/L solution is:

0.100 mol/L x 45.00 mL/1000 mL = 0.00450 mol

As per stoichiometry, one mole of Ozone reacts with two moles of KI. Therefore, the number of moles of Ozone needed to react with 0.00450 mol of KI is:

0.00450 mol KI x (1 mol Ozone / 2 mol KI) = 0.00225 mol Ozone

We can now use the Ideal Gas Law equation to calculate the volume of Ozone gas required at STP:

PV = nRT

Where P is the pressure of the gas, V is the volume, n is the number of moles, R is the gas constant (0.0821 L.atm/mol.K), and T is the temperature in Kelvin.

Since the volume of gas is to be measured at 25.0 °C and 1.00 bar, we need to convert the temperature to Kelvin:

T = (25.0 + 273) K = 298 K

Substituting these values into the Ideal Gas Law equation, we get:

V = nRT/P = (0.00225 mol)(0.0821 L.atm/mol.K)(298 K)/(1.00 bar) = 0.0548 L = 54.8 mL

Therefore, the volume of Ozone gas required is 54.8 mL, which corresponds to choice A.

Question 5

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH₂(s)+ 2H₂O(l)→ Ca(OH)₂(aq)+ 2H₂(g) A)3.77 g B)7.64 g C)15.3 g D)45.6 g

Accepted Answer

The answer of How many grams of calcium hydride are...

Question 6

Determine the mass of water formed when 12.5 L NH₃ (at 298 K and 1.50 bar)is reacted with 18.9 L of O₂ (at 323 K and 1.1 bar). 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g) A)16.7 g H₂O B)20.7 g H₂O C)37.7 g H₂O D)13.8 g H₂O E)27.9 g H₂O

Accepted Answer

The answer of Determine the mass of water formed when...

Question 7

Which of the gases in the graph below has the smallest molar mass? 
A)A
B)B
C)C
D)D
E)There is not enough information to determine the answer.

Accepted Answer

The gas with the smallest molar mass will have the highest average speed at a given temperature, according to the Kinetic Molecular Theory. This is because lighter gases have less mass to move around and thus can move faster than heavier gases. From the graph, gas A has the highest average speed at a given temperature, indicating that it has the smallest molar mass.

Question 8

The action of some commercial drain cleaners is based on the following reaction: 2NaOH(s)+ 2Al(s)+ 6H₂O(l)→ 2NaAl(OH)₄(s)+ 3H₂(g) What is the volume of H₂ gas formed at STP when 6.32 g of Al reacts with excess NaOH? A)3.50 L B)5.25L C)7.98 L D)8.59L

Accepted Answer

First, we need to find the moles of Al using its molar mass:

6.32 g Al ÷ 26.98 g/mol = 0.234 moles Al

According to the balanced equation, for every 2 moles of Al, 3 moles of H2 gas are produced. We can use this ratio to find the moles of H2 gas produced:

0.234 moles Al × (3 moles H2/2 moles Al) = 0.351 moles H2

Now we can use the Ideal Gas Law, PV=nRT, to find the volume of H2 gas at STP (standard temperature and pressure, 0°C and 1 atm). We know that at STP, one mole of gas occupies 22.4 L, so we can use this conversion factor to find the volume of gas:

V = nRT/P = (0.351 mol)(0.0821 L·atm/mol·K)(273 K)/(1 atm) = 7.98 L

Therefore, the volume of H2 gas formed at STP when 6.32 g of Al reacts with excess NaOH is 7.98 L. The correct choice is C.

Question 9

Calculate the root mean square velocity of nitrogen molecules at 25 °C. A)729 m s^-1 B)515 m s^-1 C)149 m s^-1 D)297 m s^-1

Accepted Answer

The root mean square velocity (u) of a gas is given by the formula u = √(3RT/M), where R is the gas constant, T is the temperature in Kelvin, and M is the molar mass of the gas. The molar mass of nitrogen (N2) is 28 g/mol. Converting 25 °C to Kelvin gives 298 K. Plugging in these values, we get u = √(3 x 8.31 J/mol-K x 298 K / 28 g/mol) = 515 m/s. Thus, the best choice is B.

Question 10

Determine the volume of SO₂ (at STP)formed from the reaction of 96.7 g of FeS₂ and 55.0 L of O₂ (at 398 K and 1.20 bar).The molar mass of FeS₂ is 119.99 g mol^-1. 4FeS₂(s)+ 11O₂(g)→ 2Fe₂O₃(s)+ 8SO₂(g) A)36.1 L B)45.3 L C)18.1 L D)27.6 L E)32.5 L

Accepted Answer

The answer of Determine the volume of SO₂ (at STP)formed...

Question 11

Calculate the root mean square velocity of molecular hydrogen at 251.0 K. A)1692 m s^-1 B)1875 m s^-1 C)1342 m s^-1 D)715.6 m s^-1 E)1762 m s^-1

Accepted Answer

The answer of Calculate the root mean square velocity of...

Question 12

Which of the gases in the graph below has the largest molar mass? 
A)A
B)B
C)C
D)D
E)There is not enough information to determine the answer.

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The answer of Which of the gases in the graph...

Question 13

Which statement is TRUE about kinetic molecular theory?
A)A single particle does not move in a straight line.
B)The size of the particle is large compared to the volume.
C)The collisions of particles with one another are completely elastic.
D)The average kinetic energy of a particle is not proportional to the temperature.

Accepted Answer

The kinetic molecular theory states that the collisions between particles in a gas are completely elastic, meaning there is no net loss or gain of kinetic energy during collisions. Choice A is false because particles in a gas can move in a straight line unless they collide with other particles or the walls of the container. Choice B is false because the size of the particle is negligible compared to the volume of the gas. Choice D is false because the temperature of a gas is directly proportional to the average kinetic energy of its particles.

Question 14

At what temperature does argon have a root mean square velocity of 492 m s^-1? A)321 K B)291 K C)340 K D)388 K E)409 K

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Question 15

Determine the total volume of all gases (at STP)formed when 50.0 mL of TNT C₃H₅(NO₃)₃,d = 1.60 g mL^-1,molar mass = 227.10 g mol^-1)reacts according to the following reaction: 4C₃H₅(NO₃)₃(l)→ 6N₂(g)+ O₂(g)+ 12CO₂(g)+ 10H₂O(g) A)4.93 L B)58.0 L C)29.6 L D)448 L E)175 L

Accepted Answer

First, we need to convert the volume of TNT from milliliters to liters: 50.0 mL = 0.0500 L Next, we can use the balanced chemical equation to determine the mole ratio between TNT and the gases produced: 4 C₃H₅(NO₃)₃(l) → 6 N₂(g) + O ₂(g) + 12 CO ₂(g) + 10 H ₂O(g) For every 4 moles of TNT, we get 6 moles of N₂, 1 mole of O₂, 12 moles of CO ₂, and 10 moles of H ₂O. We can use the molar mass of TNT (227.10 g mol^-1) to convert the given amount of TNT to moles: 0.0500 L TNT x (1.60 g/mL) / (227.10 g/mol) = 0.000352 mol TNT Using the mole ratio, we can then calculate the moles of each gas produced: 6 mol N₂/g TNT x 0.000352 mol TNT = 0.00211 mol N₂ 1 mol O₂/g TNT x 0.000352 mol TNT = 0.000352 mol O₂ 12 mol CO ₂/g TNT x 0.000352 mol TNT = 0.00422 mol CO ₂ 10 mol H ₂O/g TNT x 0.000352 mol TNT = 0.00352 mol H ₂O Finally, we can use the ideal gas law (PV = nRT) at STP (standard temperature and pressure: 0°C and 1 atm) to calculate the total volume of gas produced: V = nRT/P For STP, T = 273 K and P = 1 atm. The gas constant R can be expressed as 0.0821 L atm/mol K. V N₂ = (0.00211 mol) x (0.0821 L atm/mol K) x (273 K) / (1 atm) = 0.0496 L V O₂ = (0.000352 mol) x (0.0821 L atm/mol K) x (273 K) / (1 atm) = 0.00828 L V CO ₂ = (0.00422 mol) x (0.0821 L atm/mol K) x (273 K) / (1 atm) = 0.0990 L V H ₂O = (0.00352 mol) x (0.0821 L atm/mol K) x (273 K) / (1 atm) = 0.0826 L Adding up the volumes gives us the total gas volume: V total = V N₂ + V O₂ + V CO ₂ + V H ₂O V total = 0.0496 L + 0.00828 L + 0.0990 L + 0.0826 L = 0.239 L Therefore, the answer is B) 58.0 L, the closest approximation to 0.239 L when rounded to one significant figure.

Question 16

Calculate the molecular weight of a gas that has a root mean square velocity of 269 m s^-1 at 381 K. A)131 g mol^-1 B)83.8 g mol^-1 C)39.9 g mol^-1 D)20.2 g mol^-1 E)4.00 g mol^-1

Accepted Answer

The answer of Calculate the molecular weight of a gas...

Question 17

How many molecules of XeF₆are formed from 12.9 L of F₂ (at 298 K and 2.635 bar)according to the following reaction? Assume that there is excess Xe. Xe(g)+ 3F₂(g)→ XeF₆(g) A)1.21 × 10²³ molecules XeF₆ B)8.25 × 10²³ molecules XeF₆ C)2.75 × 10²³ molecules XeF₆ D)7.29 × 10²³ molecules XeF₆ E)1.37 × 10²³ molecules XeF₆

Accepted Answer

The answer of How many molecules of XeF₆are formed...

Question 18

Determine the theoretical yield and the percent yield if 21.8 g of K₂CO₃ is produced from reacting 27.9 g KO₂ with 29.0 L of CO₂ (at STP).The molar mass of KO₂ is 71.10 g mol^-1 and K₂CO₃is 138.21 g mol^-1. 4KO₂(s)+ 2CO₂(g)→ 2K₂CO₃(s)+ 3O₂(g) A)27.1 g,80.4% yield B)179 g,12.2% yield C)91.7 g,23.8% yield D)206 g,10.6% yield E)61.0 g,35.7% yield

Accepted Answer

1. Calculate the moles of KO₂: 27.9 g / 71.10 g mol^-1 = 0.39 mol KO₂ 2. Calculate the moles of CO₂: 29.0 L / 22.4 L mol^-1 = 1.30 mol CO₂ 3. Determine the limiting reagent: 4 KO₂(s) + 2 CO₂(g) → 2 K₂CO₃(s) + 3 O2(g) From the balanced chemical equation, it can be seen that 4 moles of KO₂ react with 2 moles of CO₂ to produce 2 moles of K₂CO₃. Therefore, the moles of CO₂ should be multiplied by the factor of 2/1 to determine the moles of K₂CO₃ produced. 0.39 mol KO₂ × (2 mol K₂CO₃ / 4 mol KO₂) = 0.195 mol K₂CO₃ (limiting reagent) 1.30 mol CO₂ × (2 mol K₂CO₃ / 1 mol CO₂) = 2.60 mol K₂CO₃ 4. Calculate the theoretical yield of K₂CO₃: 0.195 mol K₂CO₃ × 138.21 g mol^-1 = 27.0 g K₂CO₃ 5. Calculate the percent yield: % Yield = (Actual Yield / Theoretical Yield) × 100 % Yield = (21.8 g / 27.0 g) × 100 = 80.7% The closest answer choice is A, which is 80.4% yield. Therefore, the best choice is A.

Question 19

A mixture of 1.0 mol He and 1.0 mol Ne are at STP in a rigid container.Which of the following statements is TRUE?
A)Both gases have the same average kinetic energy.
B)Both gases contribute equally to the density of the mixture under these conditions.
C)Both gases have the same molecular speed.
D)The mixture has a volume of 22.4 L.
E)All of the above are true.

Accepted Answer

The answer of A mixture of 1.0 mol He and...

Question 20

Identify the gas particle that travels the fastest. A)H₂ B)O₂ C)Ne D)N₂ E)CO

Accepted Answer

The answer of Identify the gas particle that travels the...

Quiz 5: Gases

An unknown gas has a root mean square velocity of 332 m s^-1 at 313 K.Identify the unknown gas.

What is the temperature if krypton has a root mean square velocity of 348 m $s ^ { - 1 }$ ?

Identify the gas particle that travels the slowest.

How many millilitres of ozone gas at 25.0 °C and 1.00 bar are needed to react with 45.00 mL of a 0.100 mol L^-1 aqueous solution of KI according to the chemical equation shown below? O₃(g) + 2I^-(aq) + H₂O(l) → O₂(g) + I₂(s) + 2OH^-(aq)

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH₂(s) + 2H₂O(l) → Ca(OH) ₂(aq) + 2H₂(g)

Determine the mass of water formed when 12.5 L NH₃ (at 298 K and 1.50 bar) is reacted with 18.9 L of O₂ (at 323 K and 1.1 bar) . 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)

Which of the gases in the graph below has the smallest molar mass?

The action of some commercial drain cleaners is based on the following reaction: 2NaOH(s) + 2Al(s) + 6H₂O(l) → 2NaAl(OH) ₄(s) + 3H₂(g) What is the volume of H₂ gas formed at STP when 6.32 g of Al reacts with excess NaOH?

Calculate the root mean square velocity of nitrogen molecules at 25 °C.

Determine the volume of SO₂ (at STP) formed from the reaction of 96.7 g of FeS₂ and 55.0 L of O₂ (at 398 K and 1.20 bar) .The molar mass of FeS₂ is 119.99 g mol^-1. 4FeS₂(s) + 11O₂(g) → 2Fe₂O₃(s) + 8SO₂(g)

Calculate the root mean square velocity of molecular hydrogen at 251.0 K.

Which of the gases in the graph below has the largest molar mass?

Which statement is TRUE about kinetic molecular theory?

At what temperature does argon have a root mean square velocity of 492 m s^-1?

Determine the total volume of all gases (at STP) formed when 50.0 mL of TNT C₃H₅(NO₃) ₃,d = 1.60 g mL^-1,molar mass = 227.10 g mol^-1) reacts according to the following reaction: 4C₃H₅(NO₃) ₃(l) → 6N₂(g) + O₂(g) + 12CO₂(g) + 10H₂O(g)

Calculate the molecular weight of a gas that has a root mean square velocity of 269 m s^-1 at 381 K.

How many molecules of XeF₆are formed from 12.9 L of F₂ (at 298 K and 2.635 bar) according to the following reaction? Assume that there is excess Xe. Xe(g) + 3F₂(g) → XeF₆(g)

Determine the theoretical yield and the percent yield if 21.8 g of K₂CO₃ is produced from reacting 27.9 g KO₂ with 29.0 L of CO₂ (at STP) .The molar mass of KO₂ is 71.10 g mol^-1 and K₂CO₃is 138.21 g mol^-1. 4KO₂(s) + 2CO₂(g) → 2K₂CO₃(s) + 3O₂(g)

A mixture of 1.0 mol He and 1.0 mol Ne are at STP in a rigid container.Which of the following statements is TRUE?

Identify the gas particle that travels the fastest.

Quiz 5: Gases

An unknown gas has a root mean square velocity of 332 m s-1 at 313 K.Identify the unknown gas.

What is the temperature if krypton has a root mean square velocity of 348 m s−1s ^ { - 1 }s−1 ?

Identify the gas particle that travels the slowest.

How many millilitres of ozone gas at 25.0 °C and 1.00 bar are needed to react with 45.00 mL of a 0.100 mol L-1 aqueous solution of KI according to the chemical equation shown below? O3(g) + 2I-(aq) + H2O(l) → O2(g) + I2(s) + 2OH-(aq)

How many grams of calcium hydride are required to produce 4.56 L of hydrogen gas at 25.0 °C and 0.975 bar according to the chemical equation shown below? CaH2(s) + 2H2O(l) → Ca(OH) 2(aq) + 2H2(g)

Determine the mass of water formed when 12.5 L NH3 (at 298 K and 1.50 bar) is reacted with 18.9 L of O2 (at 323 K and 1.1 bar) . 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)