Question

Given the provided data, determine the value of

q on dissolving your samples of urea in 40.0 ml of water.
Mass of urea: 3.478 g
Initial temperature: 23.8°C
Final temperature: 26.3°C
a) 45.6 J
b) 78.9 J
c) 92.3 J
d) 105.1 J

Answer 1

To find the value of q, we use the heat equation, multiplying the mass of water (40.0 g) by water's specific heat capacity (4.18 J/g°C) and the temperature change (2.5°C). The product of these values should give the heat involved in the dissolution of urea in water; however, the calculation result is not among the provided answer choices.

Step-by-step explanation:

The question asks us to determine the value of q, the heat absorbed or released during the dissolving process of urea in water. Using the formula q = m × c × ΔT, where:

• m equals the mass of the solvent (water) in grams,
• c is the specific heat capacity of the solvent (water) which is 4.18 J/g°C,
• ΔT is the change in temperature,

We can calculate the heat involved in the dissolution.

First, converting the volume of water to mass (since 1 mL of water approximately equals 1 g), we have 40.0 g of water. Then using the initial and final temperatures provided, ΔT is 26.3°C - 23.8°C = 2.5°C.

Now, substituting the values into the formula:

q = 40.0 g × 4.18 J/g°C × 2.5°C = 418 J.

However, none of the answer choices match this calculation. Without rounding, the computation is exact. It seems there might be a mistake in the question's answer choices or the details provided.