Units and Conversions
Convert 25.0 °C into Kelvin.
298.2 K
How are pressure and volume related (assuming temperature does not change)?
inversely proportional (P1 V1 = P2 V2), Boyles Law
A balloon contains 149.6 mL of gas at a pressure of 567 torr. If the temperature doesn’t change, what is the volume of the gas at a pressure of 981 torr?
86.5 mL
A balloon is filled with 715 torr of hydrogen gas and 345 torr of nitrogen gas. What is the mole fraction of each gas?
The mole fraction of hydrogen is 0.675, and the mole fraction for nitrogen is 0.325
Dry ice has a temperature of 195 K. What is that temperature in degrees Celsius?
-78 deg C
How are volume and temperature related, assuming pressure does not change?
directly proportional (V1 / T1 = V2 / T2), Charles Law
A flexible container starts with a volume of 16.7 liters at a temperature of 25.0 °C. If the pressure doesn’t change, what is the volume if the temperature rises to 150.0 °C?
23.7 L
A container holds 0.54 moles of argon gas, 0.92 moles of hydrogen gas, and 0.45 moles of nitrogen gas. If the total pressure of the gases is 5.1 atm, what is the partial pressure of each gas?
The partial pressures are 1.4 atm for argon, 2.4 atm for hydrogen, and 1.2 atm for nitrogen
Which temperature scale is considered absolute and why?
Kelvin, you can never get to 0 degree Kelvin
Describe when a gas acts more ideally in terms of temperature, pressure, moles
Gases behave more variably at lower pressures and higher temperatures.
A gas-filled balloon has a volume of 15.6 liters at ground level, where the temperature is 25.0 °C and the pressure is 1.01 atm. It rises to an altitude where the temperature is -12.1 °C, and the pressure is 0.10 atm. What is the volume of the balloon?
140 L
mole fractions of all substances in a reaction always add up to what?
1
How many liters of hydrogen are made at 25.0 °C and 1.12 atm when 25.0 grams of magnesium react with excess HCl according to the following equation? Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
22.5 L
Describe boiling point in terms of water vapor pressure and external air pressure.
The point at which external air pressure equals a liquid's vapor pressure
How many moles of water vapor are present in a 615-mL container at 21.5 °C and 745 torr?
0.0249 moles
If the mole fraction for a substance is 0.5, and the total pressure is 1000.0 torr, what is P of substance divided by total pressure?
0.5. (pressure of the substance = 500 torr)
A chemist wants to make 6 liters of ammonia according to the following reaction: 3H2 (g) + N2 (g) → 2NH3 (g) How many liters of hydrogen will she need at STP?
9L
N/m^2, Pascal, atm, mmHg, torr
How far is it reasonable to extrapolate data?
a distance smaller than the range over which one has data
What is the volume of 100.0 grams of ammonia (NH3) at 84.5 °C and a pressure of 869 torr?
151 L
A chemist collects gas in a reaction over water. The pressure of what is collected is 1 atm. If the reaction is done at 60 deg. C. What is the pressure of the reaction product? (table p. 311)
610.6 torr
A chemist makes oxygen gas by the decomposition of hydrogen peroxide: 2H2O2 (aq) → 2H2O (l) + O2 (g) He collects the oxygen over the water in which the reaction is taking place. If he collects 1.45 liters of oxygen at 0.921 atm and 30.0 °C, how many moles of oxygen gas did he make? (You can use the table on page 311 for this.)
The chemist made 0.0512 moles.