Calc Mass A -> Moles B: 2.5x10^5 kg H2SO4->?Moles H3PO4

[Qube]

Equation: 3H2SO4 + Ca3(PO4)2 + 6H20 -> 3[CaSO4×2H2O] + 2H3PO4

Problem: If 2.5×10^5 kg of H2SO4 react, how many moles of H3PO4 can be made?
Equations used:

1) kilograms to grams (multiply kilograms by 10^3)

2) Mass to moles (divide given mass by mass of one mole)

3) Moles of substance A to moles of substance B (use ratios given in balanced equations above)
1) Convert mass in kg to g by multiplying by 10^3

2) Convert the grams of H2SO4 to moles of H2SO4; divide the grams of H2SO4 (2.5×10^8 g) by the grams in 1 mole of H2SO4. Answer: 2.5×10^6 moles of H2SO4 are in 2.5×10^8 grams of H2SO4. Is that right?

3) Now I have to see how much H3PO4 will be produced. I take 2.5×10^6 moles of H2SO4 and multiply it by 2/3 or 0.66.

Why multiply by 2/3? That's 2 moles of H3PO4 for 3 moles of H2SO4, which I got from the given equation. In other words, for every 2 moles of H3PO4, 3 moles of H2SO4 are required.

Am I correct in my steps to the answer? The teacher didn't get around to telling us the answer on this problem today. I have a quiz next class period so I'd like to know if I'm right or not.

By the way, my final answer was 1.7×10^6 moles of H3PO4 is produced.

 

[Borek]

OK

You may try to read stoichiometric calculations page (and next ones - select them from the left menu) for more details. But so far you are doing great.