If 1 kg of each substance in the table changes temperature by 15°C, which substance absorbed the greatest amount of thermal energy?
Substance
Specific Heat Capacity
(kJ/(kg;°C))
Air
1.01
Plastic
2.60
Water
4.18
Wood
1.68

Water.

Explanation:

To know which of the substance that will absorbed the greatest amount of thermal energy, we'll simply determine the amount of energy absorbed by each substance.

This is illustrated below:

For Air:

Mass (M) = 1 kg

Change in temperature (ΔT) = 15 °C

Specific heat capacity (C) = 1.01 KJ/Kg°C

Heat Absorbed (Q) =..?

Q = MCΔT

Q = 1 x 1.01 x 15

Q = 15.15 KJ

Therefore, the heat absorbed by air is 15.15 KJ.

For Plastic:

Mass (M) = 1 kg

Change in temperature (ΔT) = 15 °C

Specific heat capacity (C) = 2.60 KJ/Kg°C

Heat Absorbed (Q) =..?

Q = MCΔT

Q = 1 x 2.60 x 15

Q = 39 KJ

Therefore, the heat absorbed by plastic is 39 KJ.

For Water:

Mass (M) = 1 kg

Change in temperature (ΔT) = 15 °C

Specific heat capacity (C) = 4.18 KJ/Kg°C

Heat Absorbed (Q) =..?

Q = MCΔT

Q = 1 x 4.18 x 15

Q = 62.7 KJ

Therefore, the heat absorbed by water is 62.7 KJ.

For Wood:

Mass (M) = 1 kg

Change in temperature (ΔT) = 15 °C

Specific heat capacity (C) = 1.68 KJ/Kg°C

Heat Absorbed (Q) =..?

Q = MCΔT

Q = 1 x 1.68 x 15

Q = 25.2 KJ

Therefore, the heat absorbed by Wood is 25.2 KJ.

Summary:

Substance >>>>> Heat Absorbed

Air >>>>>>>>>>>> 15.15 KJ.

Plastic >>>>>>>>> 39 KJ

Water >>>>>>>>>> 62.7 KJ

Wood >>>>>>>>>> 25.2 KJ.

From the above calculations, we can see that water will absorb the greatest amount of thermal energy.