Answer:
150 g (0.15 kg)
Explanation:
From the equation, 2 mol Caâ‚‚(POâ‚„)â‚‚ give us 1 mol Pâ‚„.
To calculate the weight, we need the molecular weights (Mw) of the elements:
Mw Ca= 40 g
Mw P= 31 g
Mw O= 16 g
2 mol Caâ‚‚(POâ‚„)â‚‚= 2 x (3 x (40g) + 2 x (31g) + 8 x (16 g))
2 mol Caâ‚‚(POâ‚„)â‚‚= 620 g
1 mol Pâ‚„= 4 x (31g) = 124 g
So, we can obtain 124 g of Pâ‚„ from 620 g Caâ‚‚(POâ‚„)â‚‚ (this is our recipe!)
Now, if the 75% of 1kg (=1000g) is Caâ‚‚(POâ‚„)â‚‚, we have:
1000 g x 75/100= 750 g Caâ‚‚(POâ‚„)â‚‚
Finally:
620 g Caâ‚‚(POâ‚„)â‚‚ ---------------------- 124 g Pâ‚„
750 g Caâ‚‚(POâ‚„)â‚‚ ------------------------X= (750 g x 124 g)/620 g= 150 g