Unit 7 Test Review HC

Which is a not basic assumption of the kinetic–molecular theory?

• The average kinetic energy is directly related to the temperature.

• Particles do not occupy any volume.

• Particles are not attracted or repelled by each other.

• The pressure of a gas is directly proportional to its temperature.

• Particles are in random motion.

Answer explanation

Pressure and temperature relationship is not a part of KMT.

Tags

NGSS.HS-PS1-5

At the same temperature and pressure which gas has the greatest average velocity?

• The velocities are the same.

Answer explanation

Small mass = faster

Tags

NGSS.HS-PS3-2

• number of atoms.

• number of grams.

• number of molecules.

• average velocity.

• density.

Answer explanation

Same amount of moles = same amount of molecules

A sample of gas at 2.20 atm of pressure occupies a volume of 500.0 L. If the volume is decreased to 125,000 mL and the temperature is held constant, what is the new pressure in atmospheres?

• 1.76

• 2.93

• 28400

• 0.550

• 8.80

Answer explanation

This uses Pressure and Volume (Boyle's Law).

P₁V₁ = P₂V₂

Keep in mind, this equation is different from ALL of the others.

• 3.68 psi

• 127 kPa

• 1.90 x 10³ mmHg

• 3040 Torr

• 5.07 x 10⁵ Pa

Answer explanation

This question uses Pressure and Temperature (Gay-Lussac's Law).

P₁T₂ = P₂T₁

Remember to convert ℃ to Kelvin before calculating. You will also need to convert the pressure using all of the constants.

Tags

NGSS.HS-PS3-4

• 44.0 g

• 6.08 g

• 9.54 x 10³ g

• 9.55 g

• 1.24 x 10⁶ g

Answer explanation

Ideal Gas Law

PV = nRT

Make sure that your pressure is in atmospheres, volume in Liters, temperature in Kelvin to calculate.

Solve for moles and then convert to grams using molar mass.

Which curve represents the relationship between the volume of an ideal gas and its moles at constant temperature and pressure?

• 
• 
• 
• 

Answer explanation

When one increases, the other also increases.

• They all exert the same pressure.

Answer explanation

Smallest moles = smallest pressure.

Tags

NGSS.HS-PS2-1

4.6 L of C₂H₂(g) reacts with an excess of oxygen at a pressure of 915 mmHg at 143°C. How many grams of water can be produced by this reaction?

• 0.324 g

• 8.47 g

• 2160 g

• 2.88 g

• 5.77 g

Answer explanation

Ideal Gas Law

PV = nRT

Remember that your pressure must be in atmospheres, volume in Liters and temperature in Kelvin to calculate.

You must write a balanced equation for this combustion reaction and solve for your final answer using Stoich.

Iron (III) oxide reacts with carbon monoxide to produce iron and carbon dioxide. If 42.3 grams of iron (III) oxide reacts with excess carbon monoxide, what volume of CO₂ would be produced if the CO₂ is collected at 2.16 atm and -14.0°C?

• 7.87 L

• 17.8 L

• 2.61 L

• 0.128 L

• 5.22 L

Answer explanation

You must start with a balanced equation and Stoich to find the moles that you will use in the Ideal Gas Law.

PV = nRT

Remember your pressure must be in atmospheres, your volume in Liters and temperature in Kelvin to calculate.

Tags

NGSS.HS-PS1-2