Energetics

Question 1

Energy released q

Answer 1

q=mc delta T

Question 2

formation data

Answer 2

Arrows up
products- reactants

Question 3

combustion data

Answer 3

reactants - products
arrows down

Question 4

mean bond enthalpy

Answer 4

+-q/n

Question 5

Hess’ law

Answer 5

The enthalpy change for a reaction is independent of the route taken

Question 6

explain why obtained data is less exothermic

Answer 6

-non-standard conditions
-evaporation
-heat loss to container
-poor stirring

Question 7

calorimetry: combustion

Answer 7

mass of spirit burner and fuel with cap is recorded
known volume of water in beaker and temperature is recorded
fuel heats up water, flame is held close with heat proof guards to minimise heat-loss
lid is placed and mass recorded again

Question 8

Enthalpy change definition delta H

Answer 8

Heat change at constant pressure

Question 9

Why is the enthalpy of formation of an element 0?

Answer 9

By definition

Question 10

delta H mean bond enthalpy data equation

Answer 10

delta H=sum of bonds broken- sum of bonds formed