RP2 Measuring enthalpy change Flashcards
1
Q
How can you reduce uncertainty in mass measurement
A
Use a balance with a greater resolution
Use a larger mass
2
Q
How do you calculate percentage uncertainty
A
uncertainty/calculated value x 100
3
Q
Why may an experimental value for enthalpy change be different to theoretical value
A
Heat loss to surroundings
Incomplete combustion
Non standard conditions
Evaporation of water/alcohol
4
Q
How to prevent heat loss to surroundings
A
Insulate the beaker by placing it in a polystyrene cup with a lid
Avoid large temperature differences between surroundings and calorimeter
Use a bomb calorimeter
5
Q
How to improve accuracy other than heat loss
A
Read thermometer at eye level
Stir solution so temperature is evenly distributed
Use a digital thermometer more accurate and faster
