1: ENERGY

Question 1

what can store chemical potential energy

Answer 1

fuels, food and cells/batteries

Question 2

what is a closed system and what if the amount of energy is lower at the start then at the end

Answer 2

no energy is lost and no energy is gained, so for eg GPE = KE or KE = EPE
energy must have been lost through work done against air resistance or friction

Question 3

specific heat capacity practical: (6)

Answer 3

1. measure mass of metal block/water in a beaker using a top pan balance
2. place electrical heater in block/water
3. measure initial temp using a thermometer
4. turn heater on, start timer and measure pd and current using a voltmeter and ammeter
5. after set time, measure final temp and calculate temp change
6. find energy supplied using E = pt (power using P = IV) and calculate SHC

Question 4

what is power

Answer 4

the rate of energy transferred over time (watts)

Question 5

how is thermal energy lost in buildings

Answer 5

through conduction: as vibrating particles go through walls, windows, doors etc and transfer energy to outside surroundings. can be minimised through cavity wall insulation, double glazing, etc

Question 6

insulation practical (3)

Answer 6

1. pour hot water into can/beaker and start timer when temp falls to chosen initial temp
2. after set time, measure final temp
3. repeat with diff types of insulation around can/beaker or diff numbers of layers of the same insulation

Question 7

what is hydroelectric and biofuel

Answer 7

hydroelectric: water behind dam has GPE, falls to produce elec
biofuel: biomass burned to produce heat