Energetics

Question 1

Steps to measure enthalpy change using cooling curve 6 marker energetics

Answer 1

1- measure 50 cm3 of water using a measuring cylinder
-add to a polystyrene cup
add known mass of solid
-weigh my difference

2- record initial temp for 4 minutes to establish room temp
- add solid and record temp at regular intervals until a trend is seen
- extrapolate back to the point of addition to get a maximum - theoretical delta t final
- Q=MC@T
@H = Q/n

Question 2

sources of error and how to improve

Answer 2

• heat loss to surroundings
• incomplete combustion
• heat can pass through metal calorimetry
• reduce distance between water and flame
• put a lid on calorimeter
• use polystyrene cup instead of metal calorimetry
• cover with sleeve to insulate