Question

The quantity of heat necessary to raise the temperature of $60$ g of metal X from $30^\circ C$ to $54^\circ C$ is (Molar heat capacity of metal X = $25$ J mol$^{-1}$ K$^{-1}$ and molar mass = $30$ g mol$^{-1}$)

• A. $1.02$ kJ
• B. $1.20$ kJ
• C. $1.25$ kJ
• D. $2.40$ kJ
• E. $1.80$ kJ

Hint:

If molar heat capacity is given, first convert mass into moles, then use $Q=nC\Delta T$.

Answer 1

The Correct Option is B

Concept: Chemistry - Heat Capacity. [ Q=nC\Delta T ]
Step 1: Find number of moles. [ n=\frac{60}{30}=2 ]
Step 2: Find temperature rise. [ \Delta T=54-30=24K ]
Step 3: Calculate heat required. [ Q=nC\Delta T ] [ Q=2 \times 25 \times 24=1200\text{ J} ]
Step 4: Convert into kJ. [ 1200\text{ J}=1.20\text{ kJ} ]
Step 5: Final answer. [ \boxed{1.20\text{ kJ}} ]
Hence, correct option is (B).