Chapter 11 Chemistry Homework Answers:
Definitions:
Pressure is the force per unit area on a surface. A Newton is A
barometer is a devise to measure atmospheric pressure.
Millimeters of mercury, torr, atmospheres and pascals are
all units of pressure. Dalton’s law of partial pressure states
that the total pressure of a gas is the sum of the partial
pressures of the component gases. Boyles Law states that the
volume of a fixed mass of gas varies inversely with pressure at
a constant temperature. Absolute zero is the lowest possible T
and is 0 degrees K, and -273 degrees C. Charles Law states that
the volume of a fixed mass of gas at constant pressure varies
directly with temperature K. Gay-Lussac’s Law states that the
pressure of a fixed mass of gas at constant volume varies
directly with the K temperature. The Combined Gas Law
expresses the relationship between pressure, volume and
temperature of a fixed amount of gas. Avagadro’s Law states
that equal volumes of gases at the same T and P contain equal
numbers of molecules. The Standard Molar Volume of a Gas
is the volume occupied by one mole of a gas at STP= 22.4 L. The
Ideal Gas Law is the mathematical relationship among P, V, T
and the number of moles of a gas. The Ideal Gas Constant is
0.082 L atm/mol K. Graham’s Law of Effusion states that the
rates of effusion of gases at the same T and P are inversely
proportional to the square roots of their molar masses.
Practice Problems:
1.a. due to collisions with the sides of the container b. pressure
is the force per unit surface area
2.a. atm, pascals and mmHg, b. I atm = 760 mm Hg, c. a pascal
is the pressure exerted by the force of one Newton acting on an
area of one square meter, d. 1 atm= 1.01 x 1023 Pa
3.a. the total pressure is a mixture of the sum of the partial
pressures of the component gases, b. they are independent of
each other
4.a. 1 atm/ 760 mm Hg = x atm/ 125 mm Hg. x=0.16 atm,
b. 1 atm/ 1.01 x 1023 Pa= 3.2 atm/ x Pa x=3.23 x 1023 Pa
c. 760 mm Hg/101.3 KPa= x mm Hg/5.38 KPa x=40.4 mmHg
5. 760 torr- (0.285 torr + 593.525 torr)= 166.19 torr
6. 742.0 torr- 42.2=699.8 torr
7.P1V1=P2V2
8. V1/T1=V2/T2
9.PV/T=k or P1V1/T1=P2V2/T2
10.a. P1V1=P2V2, V2= 100 ml b. P1=1.35 mmHg
11.a. V1/T1=V2/T2 V2= 93.3 ml b. T1= 588K – 273K= 315 C
c.V1= 81 ml
12. V1/T1=V2/T2 140/340=50/T2 T2= -152 C
13. P1V1=P2V2 (.428)(240)=(.724)(V2) V2= 141.9 ml
14.the molar ratios and the volume ratios of the gases are the
same and are reflected in the coefficients
15.a. they are proportional/ the same b. V=kn, where n= moles
16. 1 mole of any gas occupies 22.4 L at STP, so the mass varies,
but the # of molecules is the same
17. a. PV=nRT b. the relationship between pressure, volume,
moles temperature
18. a. and b. 1.08x1023 c. 2.16x1023
19. a. 1 mole b. 22.4 L/1 = 5.6 L/x x=0.25 mole c. 0.125 L/x
= 22.4 L/1 mole x= 0.006 mole d. 22.4 L/1 = 0.07 L/x
x=0.003 mole
20.a. 32g/22.4 L=8 g/x x=5.6 L b.
21.their mass
22. ammonia, because it is a smaller molecule
23.a. square root of mass of N/Square root of the mass of H=
3.74/1= H effuses 3.74 times as fast as N b. square root of
mass of Cl/square root of mass of F = 5.94/4.35= Fl effuses
1.36 times faster