During a heating period, a gas boiler transfers energy from fuel to radiator water and to a room. The fuel, the water and the room are taken together as a closed system. Assume that every energy store not shown in the table retains its initial energy.

Energy store	Initial energy	Final energy
Chemical energy store of the fuel gas	$X$	$MJ95\ \mathrm{MJ}$
Thermal energy store of the radiator water	$MJ120\ \mathrm{MJ}$	$MJ145\ \mathrm{MJ}$
Thermal energy store of the room	$MJ210\ \mathrm{MJ}$	$MJ225\ \mathrm{MJ}$

Which value is $X$ , the initial energy in the chemical energy store of the fuel gas?

$MJ110\ \mathrm{MJ}$

$MJ135\ \mathrm{MJ}$

$MJ120\ \mathrm{MJ}$

Energy store	Initial energy	Final energy
Chemical energy store of the fuel gas	$X$	$MJ95\ \mathrm{MJ}$
Thermal energy store of the radiator water	$MJ120\ \mathrm{MJ}$	$MJ145\ \mathrm{MJ}$
Thermal energy store of the room	$MJ210\ \mathrm{MJ}$	$MJ225\ \mathrm{MJ}$

Which value is $X$ , the initial energy in the chemical energy store of the fuel gas?

$MJ110\ \mathrm{MJ}$

$MJ135\ \mathrm{MJ}$

$MJ120\ \mathrm{MJ}$

8 Energy – forces doing work

Question 38

Markscheme

8 Energy – forces doing work

Question 38

Markscheme

8 Energy – forces doing work

Question 38

8 Energy – forces doing work Questions

8 Energy – forces doing work

Question 38

8 Energy – forces doing work Questions