Biology AQA A level questions + answers - Exchange, energy transfers + response

A 2g sample of biomass was fully combusted in a calorimeter. The volume of water in the calorimeter was 100cm^3. The increase in temperature recorded was 15.7oC. 4.18J of energy are needed to increase the temperature of 1cm^3 of water by 1oC. Use this information to calculate the heat energy released in KJ per g of biomass. Show your working. (2 marks) - correct answears100cm^3/1000 = 0.1kg 0.1x4.18x15.7= 6.56/2= 3.28KJ/g A scientist calculated the surface area of a large number of frog eggs. He found that the mean surface area was 9.73mm^2. Frog eggs are spherical. The surface area of a sphere is calculated using this equation Surface area = 4Pir^2 where r is the radius of a sphere Pi = 3.14 Use this equation to calculate the mean diameter of a frog egg. Show your working. (2 marks) - correct answears1. 9.73 = 4xPixr^2 9.73/4Pi = 0.77 = square root of 0.77 = 2. 0.8799 x 2 = 1.76mm A scientist investigated birth mass in a population of babies. She determined the birth mass of babies and grouped this information into different ranges of birth mass. Freq density is calculated using this equation. Freq density number of babies/range of mass. Draw, on figure 8, a suitable chart to show the distribution of birth mass for this population of babies. (4 marks) - correct answears1. Suitable scale 2. Fills up at least half of the graph 3. Suitable chart e.g. histogram 4. X and y axis correct A scientist investigated the affinity for oxygen of horse haemoglobin and mouse haemoglobin. Some of their results are shown in table 7.