大象传媒

Sample exam questions - ecosystems and material cycles - Edexcel Science calculations

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.

Part of Biology (Single Science)Ecosystems and material cycles

Science calculations

Maths questions often start with the command words 'calculate鈥 or 'determine'. They will then have a blank space for you to show your working. It is important that you show your working; don鈥檛 just write the answer down. You might earn marks for your working even if you get the answer incorrect.

In some maths questions you will be required to give the units. This may earn you an additional mark. Don't forget to check whether you need to do this.

Maths questions might include graphs and tables as well as calculations. Don't forget to take a ruler and calculator.

If drawing graphs, make sure you:

  1. put the independent variable on the x-axis and the dependant variable on the y-axis
  2. construct regular scales for the axes
  3. label the axes appropriate
  4. plot each point accurately
  5. decide whether the origin should be used as a data point
  6. draw a straight or curved line of best fit

If you are asked to calculate an answer and it has lots of decimal places, don't forget to use the same number of significant figures as the data in the question. For example, if two significant figures are used in the question, then usually your answer would also be to two significant figures. Don't forget to check your rounding.

Edexcel questions courtesy of Pearson Education Ltd.

Sample question 1 - Foundation

Question

A student wants to estimate the number of daisy plants in a 500 m2 field.

She uses a 1 m2 quadrat to sample the field.

The figure shows the results for the number of daisy plants counted in six areas sampled with the quadrat.

QuadratDaisy NumberMean diameter
157 cm
222 cm
369 cm
433 cm
545 cm
646 cm
Quadrat1
Daisy Number5
Mean diameter7 cm
Quadrat2
Daisy Number2
Mean diameter2 cm
Quadrat3
Daisy Number6
Mean diameter9 cm
Quadrat4
Daisy Number3
Mean diameter3 cm
Quadrat5
Daisy Number4
Mean diameter5 cm
Quadrat6
Daisy Number4
Mean diameter6 cm

Calculate the mean number of daisy plants for the six samples. [1 mark]

Sample question 2 - Higher

Question

The figure shows a food chain for organisms in a stream.

Algae 鈫 Stonefly larvae 鈫 Water beetles 鈫 Birds

In the food chain there is 2.1 脳 104 J of energy in the biomass of stonefly larvae.

90% of the energy is lost between each trophic level of the food chain. Calculate the energy value that enters the birds. [2 marks]