Question

When a 6.00g sample of KBr is dissolved in water in a calorimeter that has a total heat capacity of 2.79 kJ K⁻¹, and the temperature decreases by 0.360 K,what is the approximate heat absorbed or released during this process?

a) -1.01 kJ
b) -1.79 kJ
c) 1.01 kJ
d) 1.79 kJ

Answer 1

The heat absorbed when a 6.00g sample of KBr is dissolved, causing a temperature decrease of 0.360 K in a calorimeter with a total heat capacity of 2.79 kJ K⁻¹, is approximately 1.01 kJ. This process is endothermic as the calorimeter absorbs heat.

Thus, the correct answer is (c) 1.01 kJ.

Step-by-step explanation:

When a 6.00g sample of KBr is dissolved in water in a calorimeter with a total heat capacity of 2.79 kJ K⁻¹ and the temperature decreases by 0.360 K, the heat absorbed by the dissolution process is calculated by multiplying the heat capacity by the change in temperature. Since the temperature decreased, this indicates that the process of dissolution is endothermic, meaning heat is absorbed from the surroundings.

The formula to determine the heat (∆q) absorbed or released during a process is given by:

∆q = C × ∆T

Where:

• C is the heat capacity of the calorimeter (2.79 kJ K⁻¹)
• ∆T is the change in temperature (0.360 K)

Therefore, plugging in the values we get:

∆q = 2.79 kJ K⁻¹ × (-0.360 K)

∆q = -1.0044 kJ

Since the value is negative, it represents that heat was absorbed, and since we need to approximate the value, we round it to -1.01 kJ. Thus, the correct answer is (c) 1.01 kJ.