Exam styled questions

State two observations you made when burning the carbohydrate foods (2)

this question is asking you ‘what did you see while the food was burning’ - this can literally, I mean literally can be any little thing you see.

Answers: yellow flame, food melted or started breaking apart, smoke emerged from the food, different sized flames, food turned black etc.

Describe how you used the pipette to measure the 25cm3 of water accurately. (2)

again asking - how did you use this equipment to get water?’

(1) draw water up to the mark line and read from the bottom of the meniscus

Give one reason why a lid was used on the calorimeter (1)

remember - this is an exothermic reaction, so the answer is so that it reduces heat loss/ heat from escaping.

State one hazard in your experiment (1)

List of answers to choose from:

Burns, scalding from hot water, hair catching fire

Explain how you minimised one risk from the hazard in the previous question (2)

burns - don’t touch until cooled down, use tweezers

scalding from hot water - wait until cool before touching it

hair catching on fire - tie hair back

Your colleague repeated the investigation.

For one of the trials, they recorded an initial temperature of 23°C and a final temperature of 45°C.

They used a thermometer that measured in 1°C increments.

Calculate the total percentage error, using the initial and final readings, for this temperature rise.

understand: the thermometer measures in 1°C increments.

uncertainty = ½ = 0.5°C

we are NOT using the equation above instead:

uncertainty / value x 100

(c) Explain two ways in which you could extend your investigation.

  1. crush all the foods before burning, this is to see if surface area has an effect

  2. time how long it takes for food to burn, to see how fast fuels burn and can be used for comparison