Chem5 - Phases

Question 1

at constant pressure heat =

Answer 1

enthalpy

Question 2

what is standard temperature and pressure?

Answer 2

0 Celsius/273 K, 1atm

Question 3

what are the characteristics of an ideal gas?

Answer 3

molecules have no size or volume, do not exert a force on eachother, have compeletely elastic collisions, and the average KE of each molecule=the temperature

Question 4

what is the ideal gas law equation?

Answer 4

PV=nRTP is pressure in atmV is volume in Ln is molsR is constant, .08206 or 8.314T is temp in Kelvin

Question 5

how does a simple mercury barometer work?

Answer 5

tube of mercury closed at one end and inverted into bath of mercury, height changes depending on force of atmospheric pressure

Question 6

what is 1atm equal to?

Answer 6

1atm=760torr/760mmHg

Question 7

what is Boyle’s law?

Answer 7

PV=constant

Question 8

what is charles’ law?

Answer 8

V/T=constantgas volume is directly proportional to temperature

Question 9

what is avogadro’s law?

Answer 9

V/n=constantat constant temp and pressure, gas volume is directly proportional to # of mols

Question 10

at STP, 1 mol of gas occupies

Answer 10

22.4 L

Question 11

how do calculate mol fraction?

Answer 11

of mols of gas divided by total # of mols of gas

Question 12

what is Dalton’s law?

Answer 12

Ptotal=P1+P2+P3…

Question 13

how to calculate partial pressure?

Answer 13

total pressure of mixture * mol fraction of the gas you are trying to calculate partial pressure for

Question 14

when do gases deviate from ideal behavior?(real gases)

Answer 14

high pressure and low remperature, (molecules forced close together)

Question 15

what does the van der waals equation do?

Answer 15

approximates real pressure/volume by actually accounting for the molecular mass/complexity of each molecule

Question 16

what does the van der waals equation state?

Answer 16

Vreal>Videal and Preal<Pideal

Question 17

what is the definition of heat capacity?

Answer 17

added energy required to increase temperature of a substance by 1 kelvin

Question 18

what is the equation for heat capacity?

Answer 18

C=q/ΔT

Question 19

1 calorie(cal)=

Answer 19

4.18Jamount of energy required to raise 1g H2O by 1 degree Celsius

Question 20

1 Calorie (from food label)

Answer 20

=1000calories=4184 Joules

Question 21

what is the equation for specific heat capacity?

Answer 21

q=mcΔT

Question 22

what is the equation for heat transfer?

Answer 22

q=CΔT

Question 23

what does a coffee cup calorimeter do?

Answer 23

measures reaction at CONSTANT PRESSURE

Question 24

what does a bomb calorimeter do?

Answer 24

measures at a CONSTANT VOLUME

Question 25

what does heat of fusion refer to?

Answer 25

melting

Question 26

what does heat of vaporization refer to?

Answer 26

boiling

Question 27

melting, vaporization, and sublimation all have a ___ enthalpy sign

Answer 27

positive

Question 28

freezing, condensation, and deposition all have a __ enthalpy sign

Answer 28

negative

Question 29

what is the critical point?

Answer 29

composed of critical temp (temp at which it cannot liquefy any further)+critical pressure. any point above that is the supercritical fluid.

Question 30

how does a venturi mask work?

Answer 30

decreased pressure inside mask allows air to rush in because its pressure is greater