Question

The power of the kettle was 1.5 kW. The 0.2kg heating element took 5 seconds to heat from 20 °C to 100 °C. Calculate the specific heat capacity of water using this information.

Answer 1

Answer:

Specific heat capacity, c = 468.75 J/Kg°C

Explanation:

Given the following data;

Power = 1.5 kW to Watts = 1.5 * 1000 = 1500 Watts

Time = 5 seconds

Mass = 0.2 kg

Initial temperature = 20°C

Final temperature = 100°C

To find specific heat capacity;

First of all, we would have to determine the energy consumption of the kettle;

Energy = power * time

Energy = 1500 * 5

Energy = 7500 Joules

Next, we would calculate the specific heat capacity of water.

Heat capacity is given by the formula;

$Q = mcdt$

Where;

• Q represents the heat capacity or quantity of heat.
• m represents the mass of an object.
• c represents the specific heat capacity of water.
• dt represents the change in temperature.

dt = T2 - T1

dt = 100 - 20

dt = 80°C

Making c the subject of formula, we have;

$c = \frac {Q}{mdt}$

Substituting into the equation, we have;

$c = \frac {7500}{0.2*80}$

$c = \frac {7500}{16}$

Specific heat capacity, c = 468.75 J/Kg°C