Which expression gives the energy change when heating a mass with specific heat capacity?

Get ready for the NCEA Level 1 Energy Test. Utilize flashcards and multiple choice questions with clear explanations and hints. Prepare for success!

Multiple Choice

Which expression gives the energy change when heating a mass with specific heat capacity?

The energy change when heating a mass depends on how much stuff you have, how much energy each unit of mass needs to raise its temperature (the specific heat capacity), and how much the temperature changes. This all combines in Q = m c ΔT, where Q is the heat energy gained, m is the mass, c is the specific heat capacity, and ΔT is the temperature change (final minus initial). The units line up to joules because kg × (J/(kg·K)) × K equals J. For example, heating 2 kg of a substance with c = 3 J/(kg·K) by 5 K uses Q = 2 × 3 × 5 = 30 J. Why the other forms don’t fit: omitting c ignores how much energy is needed per unit mass to raise the temperature; omitting m ignores how much material is being heated; and dividing by mass would give energy per unit mass, not the total energy change.

The energy change when heating a mass depends on how much stuff you have, how much energy each unit of mass needs to raise its temperature (the specific heat capacity), and how much the temperature changes. This all combines in Q = m c ΔT, where Q is the heat energy gained, m is the mass, c is the specific heat capacity, and ΔT is the temperature change (final minus initial). The units line up to joules because kg × (J/(kg·K)) × K equals J. For example, heating 2 kg of a substance with c = 3 J/(kg·K) by 5 K uses Q = 2 × 3 × 5 = 30 J.

Why the other forms don’t fit: omitting c ignores how much energy is needed per unit mass to raise the temperature; omitting m ignores how much material is being heated; and dividing by mass would give energy per unit mass, not the total energy change.

More practice questions