WEEK7 - Topic 9&10

Topic 9 Stochiometry in Chemical Calculations

 

 

 

 

 

 

 

 

 

Topic 10 General Properties of Liquids and Heat Calculations

GENERAL PROPERTIES OF LIQUIDS

Can flow, no definite shape, definite volume, incompressible

Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid phase.

 

 

 

 

 

 

 

 

 

 

INTERMOLECULAR FORCES AND HYDROGEN BONDING

Intermolecular bonds between polar molecules

1. Dipople-Dipole forces

(Attraction exist between Polar molecules)

 

2. Hydrogen bondings

(FON have the strongest electronegativety/ HFON are very small

--> dipole-dipole forces are particulary strong so they are called Hydrogen Bonds)

 

Have to have..

-F,O,N directly bonds to H

-Lone pairs

 

High boiling point 

 

 

 

 

 

 

 

 

 

 

ENERGY REQUIREMENTS FOR CHANGING STATE

Heat of fushion 335 J/g

Heat of Vaporation 2259J/g

 

 

 

 

 

 

 

 

 

SPECIFIC HEAT

Heat of fusion = liquid 되기 위해 필요한 열 J (1g당)

Heat of vaporation = evaporate 하기 위해 필요한 열 J (1g당)

Specific Heat = 상태변화없이 1도 증가하는데 필요한 열 J (1g당)

 

단위가 ..

Heat of fushion , Heat of evaporation 은 J/g (왜냐하면 상태변화가 일어날때 1g당 필요한 열이라서)

Specific Heat 은 J/g.c (왜냐하면 1g 이 1c 올라가기위해 필요한 열이라서)

 

 

계산할때 문제에서 온도변화하는 동안 상태변화도 일어났다면, 나누어서 계산해야함

Heat of fushion 이랑 Heat of evaporation 은 딱 값이 있는데, Specific Heat 은 온도변화에 따라서 필요한 값이 달라짐

Specific Heat 은 q=mcT공식 써서 계산

 

 

 

 

 

 

 

CHALLENGING QUESTIONS

 

 

 

 

 

 

 

 

TOPIC NOTES SOLUTIONS AND CONCENTRATIONS

How to calculate Percent Concentration

Molarity and Dilutions