Answer:
The temperature of the iron sample from 20°C to 84°C is 20999.6 J.
Step-by-step explanation:
To determine the amount of heat needed to increase the temperature of a substance, you can use the following formula:
Q = m * c * ΔT
Where Q is the amount of heat, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature.
In your case, the mass of the iron sample is 540.6 g, the specific heat capacity of iron is 0.450 J/g · C, and the change in temperature is 84°C - 20°C = 64°C. Plugging these values into the formula, we get:
Q = 540.6 g * 0.450 J/g · C * 64°C = 20999.6 J
Therefore, the amount of heat needed to increase the temperature of the iron sample from 20°C to 84°C is 20999.6 J.