Pre-AP Chemistry

The density of an unknown gas is 2.00 grams per Liter at 3.00 atmosphere pressure and 127^oC. What is the molar mass of this gas?

• (254/3) R

• 188 R

• (800/3) R

• 600 R

A gaseous mixture containing 7.0 moles of nitrogen, 2.5 moles of oxygen, and 0.5 moles of helium exerts a total pressure of 0.90 atmosphere. What is the partial pressure of the nitrogen?

• 0.13 atm

• 0.27 atm

• 0.63 atm

• 0.90 atm

A 2.00-liter sample of nitrogen gas at 27° C and 600. millimeters of mercury is heated until it occupies a volume of 5.00 liters. If the pressure remains unchanged, the final temperature of the gas is

• 68^o C

• 120^o C

• 477^o C

• 677^o C

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A sample of 0.010 mole of oxygen gas is confined at 127°C and 0.80 atmosphere. What would be the pressure of this sample at 27°C and the same volume?

• 0.10 atm

• 0.20 atm

• 0.60 atm

• 0.80 atm

A sample of 3.0 grams of an ideal gas at 127°C and 1.0 atmosphere pressure has a volume of 1.5 liters. Which of the following expressions is correct for the molar mass of the gas? The ideal gas constant, R, is 0.08 (L ⋅ atm)/(mole ⋅ K).

• [(0.08)(400)] /[(3.0)(1.0)(1.5)]

• [(1.0)(1.5)]/ [(3.0)(0.08)(400)]

• [(0.08)(1.0)(1.5)] /[(3.0)(400)]

• [(3.0)(0.08)(400)] /[(1.0)(1.5)]

Samples of F2 gas and Xe gas are mixed in a container of fixed volume. The initial partial pressure of the F2 gas is 8.0 atmospheres and that of the Xe gas is 1.7 atmospheres. When all of the Xe gas reacted, forming a solid compound, the pressure of the unreacted F2 gas was 4.6 atmospheres. The temperature remained constant. What is the formula of the compound?

• XeF

• XeF₃

• XeF₄

• XeF₆

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

The system shown above is at equilibrium at 28 °C. At this temperature, the vapor pressure of water is 28 millimeters of mercury. The partial pressure of O2(g) in the system is

• 28 mm Hg

• 56 mm Hg

• 133 mm Hg

• 161 mm Hg

At 25°C, a sample of NH3 (molar mass 17 grams) effuses at the rate of 0.050 mole per minute. Under the same conditions, which of the following gases effuses at approximately one-half that rate?

• O₂ (molar mass 32 g/mol)

• He (molar mass 4.0 g/mol)

• CO₂ (molar mass 44 g/mol)

• Cl₂ (molar mass 71 g/mol)

NH₄NO₃(s) → N₂O(g) + 2 H₂O(g)

A 0.03 mol sample of NH₄NO₃(s) is placed in a 1 L evacuated flask, which is then sealed and heated. The NH₄NO₃(s) decomposes completely according to the balanced equation above. The total pressure in the flask measured at 400 K is closest to which of the following? ( The value of the gas constant, R, is 0.082 L atm mol^–1 K^–1)

• 3 atm

• 1 atm

• 0.5 atm

• 0.1 atm

Tags

NGSS.HS-PS1-7

A flask contains 0.25 mole of SO₂(g), 0.50 mole of CH₄(g), and 0.50 mole of O₂(g). The total pressure of the gases in the flask is 800 mm Hg. What is the partial pressure of the SO₂(g) in the flask?

• 600 mm Hg

• 250 mm Hg

• 200 mm Hg

• 160 mm Hg