Standard enthaply change of combustion

Question 1

What is standard enthaply change of combustion

Answer 1

the enthapoly change at 100kPa and temperature at 298K, when one mole of a substance is burned completely in oxygen

Question 2

What is the equation for the combustion of hydrogen

Answer 2

H2+0.5O2 —-> H20 and

2H2 +O2 —> 2H20

Question 3

How to determine enthaply change of combustion of a liquid

Answer 3

A spirit burner,

Volume of water to ploystrene cup

tempaerature of water is measured

Burner is lit

mixture is constantly stirred with the therometer

when temperature is 20 C above temperature, burner is reweighed and final temeprature is measured

Question 4

How do you calculate the enthaply change of combustion

Answer 4

1) Calculate heat energy using equation= 
m x c x At 
2) Calculate the amount of n 
n=m/M
3) Calculate combustion change
= - q/n

Question 5

What does m x c x AT stand for

Answer 5

m= mass of water heated
c= Specfic heat captacitu
AT= Tempature change

Question 6

what are the errors and assuptions of exerpemnts

Answer 6

Heat energy form burning maybe produced in buring is transferred to air and not water

Incomplete combustion as ethanol may of not burnt compltetely

condidtions maynot be standardised as water vapour could of been produced instaed of liquid water

Experiment takes along time as not all heat energy transferred to surroundings has occured.