Question

You are trying to heat up a cup of water with a butane lighter.

1) How much heat is transferred to the water if 200 g of water with a specific heat capacity of 4.184Jg°C changes from 22.3ºC to 35.7ºC? Answer in kJ.

2) If you burn 0.23 g of butane, what is the heat of combustion of butane in kJ/g?

Answer 1

Explanation:

Remark

The formula for this is

Heat = m * c * Δt

Givens

Heat = unknown

m = 200 grams

c = 4.184 Joules / grams oC

Δt = the change in temperature = 35.7 - 22.3 = 13.4

Solution

Heat = 200 * 4.184 * 13.4

Heat = 11213 Joules

Heat = 11.2 Kj

It's hard to get the correct number of sig digs because the 200 is not qualified in any way.

Part 2.

This can really puzzle you until you know that heat given up = the heat taken on. The heat taken on was 11.2 Kj. The Butane lighter must have given that heat on.

Heat of Combustion = Heat Given Up / Number grams burned.

Heat of Combustion = 11.2 Kj / 0.23 grams

Heat of Combustion = 48.8 Kj / gram