### Step 1 of 2

Given data: 20 g of NaCl dissolves in 100 g of H2O

Find: we need to calculate the heat q when 20 g of NaCl dissolve explain in kj.

**Explanation:**

we need to consider the enthalpy change of the dissolution process.

### Step 2 of 2

To calculate the heat (q) when 20g of NaCl dissolves in 100g of H2O, we need to consider the enthalpy change of the dissolution process.

The enthalpy change for the dissolution of NaCl in water is typically −3.88kJmol−1.

To calculate the heat (q) in kJ, we need to convert the mass of NaCl to moles and then multiply it by the enthalpy change.

First, let’s calculate the number of moles of NaCl:

Moles of NaCl=Mass of NaCl / Molar mass of NaCl

The molar mass of NaCl is 58.44gmol−1.

Moles of NaCl=20g / 58.44gmol−1

Next, let’s calculate the heat (q) in kJ:

q=moles of NaCl⋅enthalpy change

q=(20g / 58.44gmol−1)⋅(−3.88kJmol−1)

Calculating this expression:

q=−6.63kJ

**Explanation:**

The negative sign indicates that the process is exothermic, meaning that heat is released to the surroundings during the dissolution of NaCl in water. The magnitude of the value is -6.63kj.

##### Final solution

Therefore, the heat (q) when 20g of NaCl dissolves in 100g of H2O is approximately −6.63kJ.

Show calculations below for determining empirical formula and the end result for the empirical formula for zinc.

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