# Enthalpy change of a neutralisation reaction

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1. Mar 3, 2017

### IDK10

1. The problem statement, all variables and given/known data
Given the reaction K2CO3(s) + 2HCl(aq) → 2KCl(aq) + CO2(g) + H2O(l), I need to find the enthalpy change in J, given that:
The specific heat capacity of water is 4.2J g-1 °C-1, and
The mass change of potassium carbonate is 2.98g, and the temperature change was °6C, and the volume of acid used was 30cm3.

2. Relevant equations
ΔH = -qmΔT
number of moles of acid neutralised = number of moles of water formed

3. The attempt at a solution
Considering it is a neutralisation reaction, I did the ΔH = -qmΔT equation. So, -4.2x-2xm=x
x/(2x0.03)
But what do I use for m?

2. Mar 3, 2017

### mjc123

What undergoes a temperature change of 6°C?

3. Mar 4, 2017

### IDK10

Exothermic

We only do neutralisation, combustion and formation enthalpy changes.

4. Mar 4, 2017

### Staff: Mentor

I am afraid you have not understood nor answered the mjc's question, which points you in the right direction.

You can't blindly apply any formula without knowing what it describes.