Question

The specific heat capacity of silver is 0.24 J/°C·g. Calculate the energy required to raise the temperature of 147.0 g from 274 K to 291 K. Energy = J Calculate the energy required to raise the temperature of 1.0 mole of by 1.0°C (called the molar heat capacity of silver). Molar Heat Capacity = J/°C·mol It takes 1.25 kJ of energy to heat a sample of pure silver from 12.4°C to 15.0°C. Calculate the mass of the sample of silver. Mass = g

Answer 1

Answer:

The energy required to raise the temperature from 274 K to 294 K is

705.6 J.

The molar heat capacity is 0.24 J/°Cg.

The mass sample is 200,320.3 g.

Explanation:

To solve this problem you have to consider the following equation:

Q = m×s×Δt   where Q: energy required to raise temperature, m: mass,

s: specific heat capacity and Δt: change in temperature.

1) Given the specific heat capacity of silver (0.24 J/°Cg), the mass of silver (147.0 g) and the variation in temperature (Δt= 294 K - 274 K = 20 K). As we are talking about a variation in temperature, if we express in °C the result will be the same, 20°C.

Q = m×s×Δt = (147.0 g) x (0.24 J/°Cg) x (20 °C) = 705.6 J

So, the energy required will be 705.6 J.

2) Then you have to find the molar heat capacity of silver. The specific heat capacity is equal to molar heat capacity when the substance is a solid or liquid and has another value when the substance is a gas. In this problem, as silver is a solid its molar heat capacity will be 0.24 J/°Cmol.

3) Finally you have to find the mass of a sample that needs 125 kJ or 125000 J (Q) of energy to increase its temperature from 12.4 °C to 15.0 °C (Δt= 15.0 °C - 12.4 °C = 2.6 °C)

.Q = m×s×Δt ⇒ 125000 J = m x (0.24 J/°Cg)x (2.6 °C)

⇒ 125000 J/ (0.24 J/°Cg)x (2.6 °C) = m ⇒ m= 200320.5 g  or 200.3 kg.

The mass of the sample is 200,320.5 g.