The degree of hardness of a given sample of hard water is 60 ppm. If the entire hardness is due to `MgSO_4,` how many of `MgSO_4` is present per kilogram of hard water ?

Explanation

To solve the problem, we need to determine how much magnesium sulfate (MgSO₄) is present in a sample of hard water that has a hardness of 60 ppm (parts per million).

### Step-by-Step Solution:

1. **Understanding ppm**:
- The term "ppm" means parts per million. This indicates that in 1 million parts of the solution, there are a certain number of parts of the solute. In this case, it means that there are 60 parts of hardness-causing substances (like MgSO₄) in 1 million parts of water.

2. **Convert ppm to grams**:
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