The specific heat of octane, C₈H₁₈(l), is 2.22 J•g/K. (a) How many J of heat are needed to raise the temperature of 80.0 g of octane from 10.0 to 25.0 °C?

Key Concepts

Specific Heat Capacity

Specific heat capacity is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius (or Kelvin). It is a material-specific property that indicates how much energy is needed to change the temperature of a given mass of the substance. In this case, octane has a specific heat of 2.22 J/g·K, meaning it requires 2.22 joules of energy to increase the temperature of one gram of octane by one degree.

Heat Transfer Calculation

The heat transfer (q) required to change the temperature of a substance can be calculated using the formula q = m × c × ΔT, where m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature. This formula allows us to quantify the energy needed for temperature changes in various materials, making it essential for solving problems related to thermal energy.

Temperature Change

Temperature change (ΔT) is the difference between the final and initial temperatures of a substance. It is calculated as ΔT = T_final - T_initial. In the context of the question, the temperature change for octane is from 10.0 °C to 25.0 °C, which is a critical component in determining the total heat required for the temperature increase, as it directly influences the amount of energy needed.