Calorimetry

Question 1

Method for calorimetry when one reagent is added to another

Answer 1

Measure 25cm3 of .5moldm-3 HCl to polystyrene cup
Measure and record initial temperature 
Start timer
Record for first 3 mins but not 4th
Add 25cm3 of .5moldm-3 NaOH at 4th min
Stir with glass rod
Record temp every min from 5-10
Draw time(x) vs temperature (y) graph and extrapolate to 4th minute

Question 2

For calorimetry graph (2 reagents) What needs to be done after initla graph is plotted

Answer 2

Draw line of best fit from 1-4 mins
Draw vertical line at 4 mins to show 🔺T
Draw a line/ curve of best fit through COOLING points only
Extend back to 4th minute

Question 3

Why is calorimetry (2 reagents) never accurate

How can it be improved

Answer 3

Heat loss

Incomplete reaction

Using lid
Accounting for initial temperature of the NaOH

Question 4

Method for calorimetry with spirit burner

Answer 4

Weigh spirit burner with fuel and lid on
Measure 100cm3 water in beaker and place about spirit burner
Measure water’s initial temperature
Light wick
Allow temp to rise to 20-25 degrees
Put lid on to extinguish and record final mass

Question 5

For q=mc🔺T for 2 reagent calorimetry, what is
q
m
c

Answer 5

q= heat given out by neutralisation reaction

m = combined mass of solvents

c= specific heat capacity of water

Question 6

For q=mc🔺T for spirit burner calorimetry, what is
q
m
c

Answer 6

q= heat given out by combustion 
m= mass of water being heated
c= specific heat capacity of water

Question 7

What is n in 🔺H= q/n

Answer 7

Moles of fuel

Question 8

Why is spirit burner calorimetry rarely accurate

How can it be improved

Answer 8

Unlikely to be under standard conditions

Incomplete combustion

Heat loss

——

Use a lid
Apply a stream of O2 to flame