Question

A chemist carefully measures the amount of heat needed to raise the temperature of a sample of a pure substance from to . The experiment shows that of heat are needed. What can the chemist report for the specific heat capacity of the substance?

Answer 1

A chemist cannot determine the specific heat capacity of a substance without knowing the mass of the sample and the temperature change involved, despite measuring the amount of heat in joules.

Step-by-step explanation:

In the realm of chemistry, determining the specific heat capacity of a substance is crucial for understanding how it will react to changes in temperature. Calorimetry is the technique used to measure the thermal energy transferred, a process dependent on the temperature change, the mass of the substance, and its specific heat capacity.

To calculate the specific heat capacity (cs), we use the formula:

q = m × cs × ΔT,

where q is the amount of heat in joules, m is the mass in grams, cs is the specific heat capacity, and ΔT is the change in temperature in degrees Celsius. Rearranging the formula to solve for cs, we get:

cs = q / (m × ΔT).

However, as the question provides information with a gap (initial and final temperatures as well as the mass of the sample are missing), the chemist cannot accurately report the specific heat capacity without this supplementary data.

Answer 2

241 J/kg K.

Step-by-step explanation:

From the complete question, the mass of the sample= 0.37 kg, Final temperature of the sample =14.5°C (287.5K), the Initial temperature of the sample = -1.2°C(271.8 K).

Therefore, the Change in temperature,∆T = final temperature of the sample - initial temperature of the sample.

Hence, ∆T= 287.5 - 271.8.

∆T= 15.7 K.

Using the formula below;

Q= MC∆T-----------------------------------(1).

Where M= mass of the sample= 0.37 kg, Q = the heat required to raise the temperature and C= specific heat capacity= 1.4 kJ= 1.4 × 1000 = 1,400 J.

Slotting in the values into equation (1) above, we have;

1400= 0.37 × C × 15.7K

1400= 5.809C.

C= 241.005336546737820.

Specific heat capacity,C;

= 241 J/kg K.

The chemist will report the specific heat capacity of the substance as 241 J/kg K.