20 g of calcium reacted with phosphoric acid, while salt was formed, calculate the mass of the formed salt

| August 18, 2021 | education

To solve the problem, we write down given: m (Ca) = 20 g. Calcium reacted with phosphoric acid (H3PO4)
Find: the mass of salt formed as a result of the reaction.
Solution:
Let us write the reaction equation
Ca + H3PO4 = Ca3 (PO4) 2 + H2
Let’s arrange the coefficients
3Ca + 2H3PO4 = Ca3 (PO4) 2 + 3H2
The resulting salt is calcium phosphate (Ca3 (PO4) 2)
Let’s calculate the molar masses for calcium and calcium phosphate.
M (Ca3 (PO4) 2) = 40 * 3 + (31 + 16 * 4) * 2 = 310 g / mol
M (Ca) = 40 g / mol
Since calcium entered 3 moles, we need to multiply the molar mass by the number of moles and get: 40 * 3 = 120 g
We will sign over calcium phosphate – x g, and over calcium 20 g. Under calcium phosphate we will sign 310 g, and under calcium 120 g.
Let’s compose and solve the proportion:
x = 20 * 310/120 = 51.67 g
Answer: m (Ca3 (PO4) 2) = 51.67 g



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