solution calorimetry

Question 1

define calorimetry

Answer 1

a technique used to measure the amount of heat energy in a reaction via measuring the enthalpy change

Question 2

what are the two types of calorimetry

Answer 2

-combustion
-solution

Question 3

what is solution calorimetry used for

Answer 3

to find the enthalpy of neutralisation of a solution

Question 4

draw a diagram of the apparatus used in solution calorimetry

Question 5

1) how do we measure the volume of an acid

Answer 5

using a measuring cylinder and add it to the polystyrene cup

Question 6

2) what measurement is taken

Answer 6

record the initial temperature of the solution using a thermometer

Question 7

3) how do we measure the volume of an alkali and what do we do immediately after

Answer 7

using a measuring cylinder and add it to the polystyrene cup. Quickly seal the lid with the thermometer

Question 8

4) what do we do continuously

Answer 8

stir to ensure even temperature distribution

Question 9

5) what do we do at regular intervals

Answer 9

record the temperature until it stops changing

Question 10

5) what type of graph do we draw and why

Answer 10

draw an extrapolation graph to calculate a more accurate value for temperature change

Question 11

why cant we use an extrapolation graph for combustion calorimetry

Answer 11

because heat is lost during the reaction, in solution calorimetry heat is only lost after the reactant is added

Question 12

how does extrapolation calculate a more accurate value for temperature change

Answer 12

It removes the effect of heat lost to the surroundings

Question 13

1) what do we plot against time

Answer 13

the recorded temperatures

Question 14

2) how do we draw the baseline

Answer 14

Draw a line of best fit for the initial readings

Question 15

3) how do we draw the post reaction line

Answer 15

Draw a line of best fit for the cooling period

Question 16

4) how do we extrapolate the lines

Answer 16

extend both lines so they intersect

Question 17

5) how do we identify an accurate value for temperature change using the graph

Answer 17

the difference between the two extrapolated lines

Question 18

when calculating Q , what do you assume

Answer 18

You can use volume directly as mass because you assume the solution’s density is the same as water (1 g/cm³)

Question 19

NOTE; we only take the initial temp of the acid because we know the alkali is the same value (it’s room temp)

Question 20

I don’t get why we extrapolate

Answer 20

Heat that was lost after adding the reactant can be counteracted doing this. Heat may have been lost due to not putting the lid on quick enough.