chem 1a chapter5 exercises with answers

8/11/2019 Chem 1A Chapter5 Exercises With Answers

1/5

Chem 1A

Chapter 5 Exercises

Pressure =Area

Force; Force = Mass x Acceleration;

If mass = kg, an acceleration = m!s", Force = kg#m!s"= $e%ton &$'

If Area = m", Pressure = &kg#m!s"'!m"= $!m"= Pascal; &1 Pa = 1 $!m"'

(as Pressure) 1 atm = *+ torr &mm-g' = 1.#* psi = 11#/ kPa = 1#1/ x 15Pa

Exercises 01)

1# A person %ith a mass of *# kg stans suarel2 on ice in the ice3skating ring# 4he person is %earing

a pair of sneakers %ith a flat sole an a total surface area of /#+ x 1 31m"# &a' Calculate the pressure

exerte on the ice surface 2 that person6 &' 7hat is this pressure in atmospheres &atm' an in torr6&4he acceleration ue to gra8itational pull is 9#: m!s"'

&Ans%er) P = 191 Pa = #1:: atm = 1.#/ torr'

"# If the same person is %earing a pair of ice3skating shoes in %hich the total contact area of the shoe

laes is .#5 x 13/m", %hat is the pressure exerte 2 the laes on the ice surface6 &' Express this

pressure in atmospheres &atm' an in torr6&Ans%er) P = 1#5" x 15Pa = 1#5 atm = 1#1. x 1/torr'

Boyles Law

/# A "#5 m/of r2 air, initiall2 at 1# atm, is pumpe into a rigi 5#3< steel tank at constant

temperature# 7hat is the final air pressure in the tank6 &Ans%er) 5# atm'

.# -o% man2 cuic meters of r2 air, initiall2 at 1# atm, must e pumpe into a 5#3< steel tank atconstant temperature so that its final pressure in the tank is 1/+ atm6 &Ans%er) +#: m/'

Charless Law

5# A sample of %ater 8apor has a 8olume "5# m< at "oC an 1# atm pressure# 7hat is the 8olume of

the 8apor at 1oC an 1# atm6 &Ans%er) /1#: m


2/5

Chem 1A

Chapter 5 Exercises

Avogadros Law

:# If #15 mole of a gas sample has a 8olume of /#+1 < at "oC an 1# atm, %hat is the molar 8olume

of the gas uner the same temperature an pressure6 &Ans%er) ".#1


3/5

Chem 1A

Chapter 5 Exercises

Ideal Gas Equation: PV n!" and Gas Density# d B4

PM$

Densit2 =Eolume

Mass; Mass of gas = mole x Molar mass = nM &M = molar mass'

Densit2 &' =

E

nM; ut mole &n' = P!B4; 4hen, =

E

&PE!B4'M= PM!B4

o, gas ensit2 can e expresse 2 the formula, =B4

PM; an M =

P

B4

(as ensit2 increases as pressure an!or molar mass increase, ut ecreases as temperature increases#

4he molar mass of a gaseous sustance can e calculate from its ensit2 measure at a gi8en

temperature an pressure#

Exercises 0")

1# 1# mole of ieal gas occupies a 8olume of ""#.1. < at 1# atm pressure an "*/#15 # ?ase onthis information, e8aluate the gas constant B# If pressure is expresse in torr &instea of atmosphere'

an e8er2thing else unchange, %hat %oul e the 8alue of B6&Ans%er) +"#/+


4/5

Chem 1A

Chapter 5 Exercises

%toi&hio'etry Involving Gaseous !ea&tants or Produ&ts(

1# inc metal reacts %ith ilute h2rochloric aci to prouce h2rogen gas accoring to the follo%ing

euation)

n&s' > "-Cl&aq' nCl"&aq' > -"&g';

&a' -o% man2 milliliters &m / "&g'

A 1#"3g mixture of potassium chlorate an potassium chlorie &Cl' is place in a test3tue fitte

%ith stopper that has ruer tuing that %oul allo% "gas prouce 2 Cl/to flo% into a

grauate gas Har# If ".# m< of "%as collecte at ".oC an #9*" atm, ho% man2 moles of "%ere

prouce6 7hat percentage &2 mass' of the mixture is Cl/6 &B = #:"+


5/5

Chem 1A

Chapter 5 Exercises

"# &a' At a gi8en temperature, %hich gas has the higher a8erage molecular kinetic energ26 7hich gas

molecule, -"or ", has the greater molecular 8elocit26 &' Calculate the root-mean-square speedof

-"an "molecules, respecti8el2, at 4P# &c' 7hich gas %ill effuse at a higher rate6

&Ans%er) &a' $one K the same molecular E; &' urms&-"' = 1:. m!s; urms&"' = .+ m!s'

/# 4he effusion rate of a gaseous compoun at a certain temperature an pressure is "5# m

the same conitions, the iffusion rate of $"is 5*#1 m

2our reasoning#

&Ans%er) Cl"K larger molecular 8olume an stronger attracti8e intermolecular forces'

/# Lner %hich conitions $"gas e8iate greatl2 from ieal eha8ior) &a' higher temperature or lo%

temperature6 &' higher pressure or lo% pressure6 (i8e an explanation for each response#

&Ans%er) Beal gases approach ieal gas eha8ior uner high temperature an lo% pressure

conition#'

.# If 1# mole of ieal gas %ere confine to ""#.1 < at #oC, it %oul exert a pressure of 1# atm

&*+# torr'# Lse the 8an er 7aals euation an constants for $"an Cl"to estimate the pressure

exerte 2 1# mole of each gas in ""#.1 < at #oC#

&$") a= 1#/9

chem 1a chapter5 exercises with answers

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