Question

What is the maximum amount in moles of p2o5 that can theoretically be made from 186 g of p4 and excess oxygen?

Answer 1

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P4(s) + 10 Cl2(g) → 4 PCl5(g)


P4 + 5 O2 → 2 P2O5

(186 g P4) / (123.8950 g/mol) x (2/1) x (141.9447 g/mol) = 426 g P2O5

Answer 2

Answer : The maximum amount in moles of
`P_2O_5` is, 3 moles

Solution : Given,

Mass of
`P_4` = 186 g

Molar mass of
`P_4` = 123.88 g/mole

First we have to calculate the moles of
`P_4`.

`\text{Moles of }P_4=\frac{\text{Mass of }P_4}{\text{Molar mass of }P_4}=(186g)/(123.88g/mole)=1.50moles`

Now we have to calculate the moles of
`P_2O_5`.

The balanced chemical reaction will be,

`P_4+5O_2\rightarrow 2P_2O_5`

From the balanced reaction, we conclude that

As, 1 mole of
`P_4` react to give 2 moles of
`P_2O_5`

So, 1.50 moles of
`P_4` react to give
`2* 1.50=3moles` of
`P_2O_5`

Therefore, the maximum amount in moles of
`P_2O_5` is, 3 moles