# preparation of elemental phosphorus can be done as follows: 2Ca3(PO4)2 + 6SiO2 --> 6CaSiO3 + P4O10 and P4O10 + 10C --> P4 + 10CO calculate the % of Ca3(PO4)2 initially present in the...

preparation of elemental phosphorus can be done as follows:

2Ca3(PO4)2 + 6SiO2 --> 6CaSiO3 + P4O10

and

P4O10 + 10C --> P4 + 10CO

calculate the % of Ca3(PO4)2 initially present in the sample if 307kg of phosphate rock yields 42.5kg of elemental P4

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### 1 Answer

First, you have to ensure that the equations are balanced. It seems that both of the equations are balanced. Next, you can combine the two equations to form a single equation to show the relationship of the compounds. By doing so, you will have the chemical equation:

`2Ca_3(PO_4)_2 + 6SiO_2 + 10 C -> 6CaSiO_3 + P_4O_10 + P_4 + 10 CO`

Next, we do some stoichiometric procedure for the determination of the mass of `Ca_3(PO_4)_2` and eventually the percent mass of it in the sample.

` `

`= 212, 802.001 grams of Ca_3(PO_4)_2`

or

`= 212.80 kg of Ca_3(PO_4)_2`

To calculate the percent `Ca_3(PO_4)_2` in the sample, we divide it by the total amount of sample multiplied by 100.

`% Ca_3(PO_4)_2 = (Mass Ca_3(PO_4)_2)/(mass of sampl e) * 100`

` ` `% Ca_3(PO_4)_2= (212.80 kg)/(307 kg) * 100`

`% Ca_3(PO_4)_2 = 69.3%` --> final answer

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