What mass of a 20% nitric acid solution is required to react with 8 g of magnesium oxide?

1. 2HNO3 + MgO = Mg (NO3) 2 + H2O, check the reaction record, put a factor of 2 in front of nitric acid;

2.n (MgO) = m (MgO): M (MgO);

3. M (MgO) = 24 + 16 = 40 g / mol;

4.n (MgO) = 8: 40 = 0.2 mol;

5. looking at the reaction, we can say that nitric acid is consumed twice as much:

n (HNO3) = 0.2 * 2 = 0.4 mol;

6. M (HNO3) = 1 + 14 + 3 * 16 = 63 g / mol;

7. m (HNO3) = n * M = 0.4 * 63 = 25.2 g – got the mass of the substance contained in the solution;

8.m (acid solution) = m (HNO3 substance): w (content in fractions) = 25.2: 0.2 = 126 g.

Answer: 126 g.