Question

How many moles of phosphoric acid are contained in 65.0 ml of 0.80 M solution of H3PO4?

Answer 1

Answer on Question #78455 – Chemistry – Other

Task:

How many moles of phosphoric acid are contained in 65.0 ml of 0.80 M solution of H₃PO₄?

Solution:

Convert mL to L: 65.0 mL = 0.065 L.

$$C_m(H_3PO_4) = 0.80 \, M = 0.80 \, \text{moles/L}.$$

1) We know that molarity = moles/liter [ $C_m = n / V$ ].

2) We also know that the H₃PO₄ solution is 0.80 M so that in 1 liter of that H₃PO₄ solution there would be 0.80 moles of H₃PO₄.

3) However, we don't have 1 liter of H₃PO₄ solution, we have 0.065 L instead. So we can multiply the 0.80 moles that we would have in 1 liter by 0.065 L to get 0.052 moles of H₃PO₄.

$$\frac{0.8 \, \text{moles}}{1 \, L} \times 0.065 \, L = 0.052 \, \text{moles of } H_3PO_4$$

Answer: 0.052 moles of phosphoric acid.