Question

7.55 grams of P4 and 7.55 grams of O2 react according to the following reaction:

P4 + O2--> P4O6

If enough oxygen is available, then the P4O6 reacts further:

P4O6 + O2 --> P4O10

a. Find the limiting reagent in the formation of P4O10.
b. What mass of P4O10 is produced?
c. What mass of excess reactant remains?

Answer 1

a) The limiting reactant is O2.

b) 7.57 grams of P4O10 is produced

c) 7.53 grams P4O6 remains

Step-by-step explanation:

Step 1: Data given

Mass of P4 = 7.55 grams

Mass of O2 = 7.55 grams

Molar mass of P4 = 123.90 g/mol

Molar mass of O2 = 32 g/mol

Step 2: The balanced equations:

P4 + 3O2-→P4O6

P4O6 + 2O2 → P4O10

Step 3: Calculate moles P4

Moles P4 = mass P4 / molar mass P4

Moles P4 = 7.55 grams / 123.90 g/mol

Moles P4 = 0.0609 moles

Step 4: Calculate moles O2

Moles O2 = 7.55 grams / 32.0 g/mol

Moles O2 = 0.236 moles

Step 5: Calculate the limiting reactant

For 1 mol P4 we need 3 moles O2 to produce 1 mol P4O6

P4 is the limiting reactant. It will completely be consumed. (0.0609 moles)

O2 is in excess. There will react 3*0.0609 = 0.1827 moles

There will remain 0.236 - 0.1827 = 0.0533 moles O2

Step 6: Calculate moles P4O6

For 1 mol P4 we need 3 moles O2 to produce 1 mol P4O6

For 0.0609 moles P4 we will have 0.0609 moles P4O6

Step 7: Calculate limting reactant

There remain 0.0533 moles O2 and there are 0.0609 moles P4O6 produced

For 1 mol P4O6 we need 2 moles O2 to produce 1 mol P4O6

The limiting reactant is O2. It will completely be reacted (0.0533 moles)

There will react 0.0533/2 = 0.02665 moles

There will remain 0.0609 - 0.02665 = 0.03425 moles P4O6

This is 0.03425 moles * 219.88 g/mol = 7.53 grams P4O6

Step 8: Calculate moles P4O10

For 1 mol P4O6 we need 2 moles O2 to produce 1 mol P4O6

For 0.0533 moles O2, we'll have 0.0533/2 = 0.02665 moles P4O10

Step 9: Calculate mass P4O10

Mass P4O10 = 0.02665 moles * 283.89 g/mol

Mass P4O10 = 7.57 grams