# What is the empirical formula of - Expert Answers

1. What is the empirical formula of a compound that is 14 g calcium, 11 g oxygen, and 0.7 g hydrogen?
A. Ca(OH)2
B. CaOH
C. Ca2OH2
D. CaO2H

2. All of the following conditions of STP are true except
A.
B. 101.3 kPa
C. 24.2 L
D. 273.15 K

3. According to Boyle, pressure and volume of a confined gas are _______ proportional, and according to Charles, the volume of a gas at constant pressure is _______ proportional to its Kelvin temperature.
A. directly; not
B. not; inversely
C. directly; inversely
D. inversely; directly

4. The rate of evaporation is affected by all of the following except
A. the temperature.
B. the area of the surface.
C. the type of solid evaporating.
D. the humidity.

5. How many moles are contained in a 4.67-L sample of gas at 30°C and 199 kPa?
A. 1.7 mol
B. 3.7 mol
C. 0.37 mol
D. 11.8 mol
6. At the same temperature, steam burns are often more severe than water burns because of water's high
A. heat of vaporization.
B. density.
C. mass.
D. polarity

7. What is the volume of 55 L of gas initially at 500 K and 4.25 atm when conditions change to STP?
A. 10.5 L
B. 584.0 L
C. 127.6 L
D. 428.1 L

8. Which of the following devices can measure only atmospheric pressure?
A. Mercury tube
B. Pressure gauge
C. Tire gauge
D. Barometer

9. How many silver (Ag) atoms are in a silver bar that is 20.0 g?
A. 1.3 3 1027 Ag atoms
B. 1.8 3 1023 Ag atoms
C. 6.02 3 1023 Ag atoms
D. 1.1 3 1023 Ag atoms

10. If the temperature of an object is 335 K, how would this be expressed on the Celsius scale?
A. 273°C
B. 608°C
C. 37°C
D. 62°C
11. Which of the following statements is not accurate?
A. At constant temperature, doubling the number of gas particles in a given space will double the pressure.
B. At constant temperature, halving the number of gas particles in a given space will cut the pressure in half.
C. At constant volume and mass, increasing the temperature will cause gas particles to move faster and create more collisions.
D. At constant temperature, increasing the number of gas particles in a given space will decrease the number of collisions on the
walls of the container.

12. At which step(s) pictured on the graph below, does the temperature remain constant?
A. Heating liquid
B. Cooling solid
C. Melting
D. Condensation
13. Imagine you have two containers of gas, one labeled gas A and one labeled gas B. Gas A has an average speed of 700 m/s and gas B has an average speed of 1100 m/s. Both containers are being held at the same temperature. How could you match the average speeds of gas A and gas B?
A. Lower the temperature of gas B.
B. Reduce the volumes of both containers.
C. Lower the temperature of gas A.
D. Raise the temperature of gas B.

14. What is the mass of the 3.7 mol PbO2
?
A. 65 g PbO2
B. 0.15 g PbO2
C. 884 g PbO2
D. 825 g PbO2

15. Which of the following is true regarding phase changes?
A. Sublimation is the same as boiling.
B. Freezing is the same as sublimation.
C. Condensation is the reverse of evaporation.
D. Melting is the reverse of deposition.

16. Which of the following is true of liquids and solids?
A. Solids have a definite shape and volume whereas liquids have a definite volume but not a definite shape.
B. Solids and liquids have a definite shape of tightly packed particles.
C. Liquids have a definite shape and volume whereas solids have a definite shape but not a definite volume.
D. Liquids have fixed particles and do not expand when heated whereas solids have flowing particles that do expand when heated.

17. What is the number of moles in 42 g of NaCl?
A. 0.72 mol NaCl
B. 1.2 mol NaCl
C. 0.61 mol NaCl
D. 1.8 mol NaCl

18. The mass of a quantity of NiCl2 is 24.6 g. How many formula units are in the sample?
A. 1.9 3 1027 NiCl2
formula units
B. 3.2 3 1023 NiCl2
formula units
C. 5.3 3 10–21 NiCl2
formula units
D. 1.1 3 1023 NiCl2
formula units

19. What mass of propane (C3H8
) is needed to produce 346 g carbon dioxide in the following reaction?

A. 1.86 g C3H8
B. 346 g C3H8
C. 5075 g C3H8
D. 115 g C3H8

20. A reading shows a pressure measurement of 43 in. Hg. What is the equivalent pressure in psi?
A. 5.73 psi
B. 21.13 psi
C. 2223.13 psi
D. 26.32 psi