Question

When a 5.10-g sample of solid sodium hydroxide dissolves in 100.0 g of water in a coffee-cup calorimeter, the temperature rises from 20.5 to 33.2°C. What is the heat absorbed by the water?

Answer 1

To calculate the heat absorbed by water when sodium hydroxide dissolves, the formula q = mcΔT is used. The heat absorbed (q) calculated here is 5.3106 kJ.

Step-by-step explanation:

The question asks for the calculation of the heat absorbed by water when sodium hydroxide dissolves in it. To find out the heat absorbed, we can use the formula q = mcΔT, where q is the heat absorbed, m is the mass of the water, c is the specific heat capacity of water (4.18 J/g°C), and ΔT is the change in temperature. In this case, m = 100.0 g, ΔT = (33.2°C - 20.5°C) = 12.7°C, and c remains as 4.18 J/g°C. The calculation becomes q = (100.0 g)(4.18 J/g°C)(12.7°C).

The exact steps to perform this calculation will be:

1. Multiply the mass of the water by the specific heat capacity:
2. 100.0 g × 4.18 J/g°C = 418 J/°C
3. Multiply this value by the change in temperature:
4. 418 J/°C × 12.7°C = 5310.6 J or 5.3106 kJ (since 1 kJ = 1000 J).

Therefore, the heat absorbed by the 100.0 g of water is 5.3106 kJ.