Question

1: the hardness of a water sample (in ppm) (in terms of equivalents of caco3) containing 10–3m caso4 is : (molar mass of caso4 = 136g/mol).

Answer 1

100 parts per million is Answer

Explanation:

Number of Moles of $CaSO_4 = 10^{-3}$moles

Water having a formula of $H_2O$ and Atomic Weight = 18 g

Given, Mass of Water = 1000 g  

So, Degree of Hardness (DoH) (taking in the specific terms of Calcium carbonate or $CaCO_3$ whose atomic weight is 100 g)=

$\frac {10^{-3} \times 100}{1000} \times 10^6$

= 100 ppm  

or 100 parts per million