If 4.21 × 10^{− 3} moles of Ca²⁺ reacts with excess PO₄^{3 −} to form calcium phosphate, how many moles of the solid will form?

Question

Quizplus · Accepted Answer

The chemical equation for the reaction between calcium (Ca) and phosphorus (P) to form calcium phosphate (Ca3(PO4)2) is: 3Ca + 2P → Ca3(PO4)2. This indicates that 3 moles of calcium react with 2 moles of phosphorus to produce 1 mole of calcium phosphate. Given 4.21 × 10^1 moles of Ca, and since the reaction requires 3 moles of Ca for every 1 mole of Ca3(PO4)2 produced, the number of moles of Ca3(PO4)2 formed will be (4.21 × 10^1) / 3 = 1.40 × 10^1 moles, which corresponds to choice C when considering significant figures and the context of the question.

If 421 × 10 − 3 Moles of Ca2+ Reacts with with Excess

If 421 × 10^{− 3} Moles of Ca²⁺ Reacts with with Excess