H Chem Unit 1 Test

A sample of oxygen gas (O2) has a volume of 7.86 L at a temperature of 19 oC and a pressure of 1.38 atm. Calculate the moles of O2 molecules present in this gas sample.

0.453 mol

A flexible weather balloon contains helium gas at a volume of 855 L. Initially, the balloon is at sea level, where the temperature is 25oC and the barometric pressure is 0.947 atm. The balloon then rises to an altitude of 5500 ft, where the pressure is 0.783 atm and the temperature is 15oC. What is the change in the volume of the balloon as it ascends from sea level to 5500 ft?

1.44 x 10^2 L

A sample of an ideal gas containing 0.918 mol is collected at 742 torr pressure and 31°C. Calculate the volume.

23.5 L

A compressed gas cylinder, at 134 atm and 23oC, is in a room where a fire occurs. The fire raises the temperature of the gas to 475oC. What is the new pressure in the cylinder?

3.39 x 10^2 atm

You transfer a sample of gas at 17°C from a volume of 4.01 L and 1.10 atm to a container at 37°C that has a pressure of 1.10 atm. What is the new volume of the gas?

4.29 L

How many of the following are compounds? H2O, N2O4, NaOH, MnO2, HF

5

Convert 8.3 x 10^2 atm to torr

6.31 x 10^5 torr

3.81 mol of CO2 at STP will occupy

85.4 L

Which of the following involves no chemical change?

Boiling of water

Which of the following describes a chemical property of gold?

Gold is an inert (nonreactive) metal

Which of the following states a chemical property?

Helium is nonreactive

Which of the following statements is true of 19.0 g of F2(g) at STP?

It contains the same number of molecules as 1/2 mol of O2(g) at STP.

Which conditions of P and T are most ideal for a gas?

Low P and high T

a. 14K gold b. Pure silver c. Aluminum d. Distilled water e. Tap water f. Brass g. Tungsten h. Sodium chloride i. Air

Mixture Element Element Compound Mixture Mixture Element Compound Mixture

Which of the following gives a graph with a straight line and a y-intercept of 0?

Volume vs. temperature (K)

When analyzing ideal gases, the temperature must be measured on the Kelvin scale

a, b, and c are correct (because otherwise you could calculate a negative volume, so that you are using an absolute scale, and to directly measure the average kinetic energy of the gas particles)

An example of a pure substance is

all of these (elements, compounds, pure water, and carbon dioxide)

If temperature and pressure are held constant, the volume is _____ the number of moles in a gas.

directly proportional to

The state of matter for an object that has a definite volume but not a definite shape is

liquid

You are playing with a helium balloon on a typically warm California day. Suddenly, the Celsius temperature doubles. Which of the following is true?

The volume of the balloon will slightly increase