02 enthalphy for dummies

Question 1

full practical

Answer 1

Put polystyrene cup in a beaker for insulation and support.
• Clamp thermometer into place making sure the thermometer bulb
is immersed in liquid.
• Measure the initial temperatures of the solution (or both solutions
if 2 are used).
• Transfer reagents to cup. If a solid reagent is used then add the
solution to the cup first and then add the solid weighed out on a
balance.
• Stir mixture.
• Measure highest/lowest temperature reached.
Notes
• If reaction is slow then then exact temperature rise can be hard to obtain as cooling occurs at the same time
as the reaction takes place – to counteract this, take readings at regular intervals, plot, and extrapolate the
temperature curve back
• Errors include: heat loss/gain, approximation of specific heat capacity of solution, neglecting specific heat
capacity of calorimeter, reaction incomplete, assuming density of solution the same as water

Question 2

steps 1 -2

Answer 2

Put polystyrene cup in a beaker for insulation and support.
• Clamp thermometer into place making sure the thermometer bulb
is immersed in liquid.

Question 3

steps 3-4

Answer 3

• Measure the initial temperatures of the solution (or both solutions
if 2 are used).
• Transfer reagents to cup. If a solid reagent is used then add the
solution to the cup first and then add the solid weighed out on a
balance.

Question 4

steps 5 -6

Answer 4

• Stir mixture.
• Measure highest/lowest temperature reached.
Notes

Question 5

steps 7

Answer 5

• If reaction is slow then then exact temperature rise can be hard to obtain as cooling occurs at the same time
as the reaction takes place – to counteract this, take readings at regular intervals, plot, and extrapolate the
temperature curve back

Question 6

steps 8

Answer 6

• Errors include: heat loss/gain, approximation of specific heat capacity of solution, neglecting specific heat
capacity of calorimeter, reaction incomplete, assuming density of solution the same as water