Q4 W2 HW

Consider the reaction 4KO₂(s) + 2CO₂(g) → 2K₂CO₃(s) + 3O₂(g). How much oxygen is produced at STP if 10.5 moles of carbon dioxide are used at STP?

• 15.8 L

• 706 L

• 353 L

• 235 L

Balance the following equation:

Mg(s) + O2(g) −→ MgO(s)

Assuming the system is at STP, how many moles of MgO are produced from 4.6 L O₂?

• 1.25

• 3.08

• 0.412

• 2.54

Tags

NGSS.HS-PS1-7

Consider the following equation:

2 Mg(s) + O2(g) −→ 2 MgO(s)

How many moles of MgO are produced from 37.7 L O₂? Assume STP.

• 0.580

• 3.37

• 2.77

• 2.50

Consider the following equation:

2 Mg(s) + O₂(g) −→ 2 MgO(s)

How many grams of MgO are produced from 44.4 L O₂ ? Assume STP.

• 3.02

• 1.25

• 160

• 170

Oxygen can be produced in the laboratory by the reaction 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g). How much potassium chlorate is needed to produce 257 mL of oxygen, collected over water at 14°C and 97.6 kPa? The vapor pressure of water at 14°C is 1.60 kPa?

• 6.89 × 10⁻³

• 7.00 × 10⁻³

• 7.12 × 10⁻³

• 2.06 × 10⁻³

Calculate the mass of oxygen gas required to occupy a volume of 6 L at a pressure of 20.9 kPa and a temperature of 37°C.

• 1.56 g

• 0.408 g

• 13.1 g

• 0.0487 g

Consider two separate 25 L cylinders at STP, each containing a different gas. Which statements are true?

A. The average kinetic energy of the gases is the same.

B. The temperature of the gases is different.

C. The average molecular speed of the gases is the same.

• 5. B and C only

• 4. A only

• 3. A and B only

• 1. B only

• 2. C only

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

A sample of N₂ gas occupies a volume of 746 mL at STP. What volume would N₂ gas occupy at 155 °C at a pressure of 368 torr?

• 2415 mL

• 1792 mL

• 588 mL

• 312 mL

You fill a balloon with 1.15 L of air at 22°C and 0.850 atm pressure. You then take this balloon to a new location where the temperature is 36°C and you find that the volume has decreased to 0.963 L. What is the new pressure inside the balloon?

• 0.899 atm

• 0.982 atm

• 1.06 atm

• 0.910 atm

0.850 moles of N₂ originally at 85°C is cooled such that it now occupies 17.55 L at 1.25 atm. What is the final temperature of the gas?

• 31.4°C

• 41.4°C

• Not enough information is given.

• 65.4°C

Tags

NGSS.HS-PS3-1