Question

A 0.280 kg block of a pure material is heated from 20.0°c to 52.8°c by the addition of 3.55 kj of energy. Calculate its specific heat (in j/(kg · °c)). Identify the substance of which it is most likely composed.

1) copper
2) gold
3) iron
4) asbestos
5) aluminum

Answer 1

The specific heat of the substance is calculated to be approximately 386.7 J/(kg°C), and the substance of which it is most likely composed, based on the options provided, is aluminum.

Step-by-step explanation:

To calculate the specific heat (c) of the substance, we use the formula Q = mcΔT, where Q is the heat energy added, m is the mass, and ΔT is the change in temperature. Plugging in the known values:

Q = 3.55 kJ = 3550 J (since 1 kJ = 1000 J)

m = 0.280 kg

ΔT = 52.8°C - 20.0°C = 32.8°C

We solve for c:

c = Q / (mΔT) = 3550 J / (0.280 kg × 32.8°C)

c = 3550 J / (0.280 kg × 32.8°C) = 3550 / 9.184 J/(kg°C)

c ≈ 386.7 J/(kg°C)

To identify the substance, we compare the calculated specific heat to known values of specific heats for various materials. The closest specific heat to that calculated (386.7 J/(kg°C)) from the options provided is likely aluminum, which has a specific heat of approximately 900 J/(kg°C). Although the calculated specific heat doesn't match perfectly, it is closest to the value for aluminum when considering common materials, and therefore aluminum is the most probable identity.