Question

When 5.00 g of solid barium react with chlorine gas to produce solid barium chloride, 31.1 kJ of heat is released. Calculate the heat when 1 mole of barium chloride is produced

Answer 1

Answer: The value of
`\Delta H` for the reaction will be -854.4 kJ

Step-by-step explanation:

To calculate the number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}`

Given mass of barium = 5.00 g

Molar mass of barium = 137.33 g/mol

Putting values in above equation, we get:

`\text{Moles of barium}=(5.00g)/(137.33g/mol)=0.0364mol`

For the given chemical reaction:

`Ba(s)+Cl_2(g)\rightarrow BaCl_2(s)`

By Stoichiometry of the reaction:

1 mole of barium produces 1 mole of barium chloride

So, 0.0364 moles of barium will produce =
`\frac{1}[1}* 0.0364=0.0364mol` of barium chloride

We are given:

Energy released for 0.0364 moles of barium chloride formed is 31.1 kJ

Now, calculating the heat when 1 mole of barium chloride is produced.

By Stoichiometry of the reaction:

When 0.0364 moles of barium chloride is produced, the energy evolved is 31.1 kJ

So, when 1 mole of barium chloride is produced, the energy evolved will be =
`(31.1kJ)/(0.0364mol)* 1mol=854.4J`

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

Hence, the value of
`\Delta H` for the reaction will be -854.4 kJ