Calculate the mass of sodium hydroxide required to obtain 8.2 g of sodium phosphate.

1. Sodium phosphate can be obtained by the reaction:

3NaOH + H3PO4 = Na3PO4 + 3H2O;

2. Calculate the chemical amount of sodium orthophosphate:

n (Na3PO4) = m (Na3PO4): M (Na3PO4);

M (Na3PO4) = 23 * 3 + 31 + 4 * 16 = 164 g / mol;

n (Na3PO4) = 8.2: 164 = 0.05 mol;

3. Determine the amount of sodium alkali:

n (NaOH) = n (Na3PO4) * 3 = 0.05 * 3 = 0.15 mol;

4. We calculate the mass of sodium hydroxide using the calculation formula:

m (NaOH) = n (NaOH) * M (NaOH);

M (NaOH) = 23 + 16 + 1 = 40 g / mol;

m (NaOH) = 0.15 * 40 = 6 g.

Answer: 6 g.



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