Answer:
7.44 grams CaCl2 will produce 10.0 grams KCl.
Explanation:
The equation is balanced:
I've repeated it here, with the elements corrected for their initial capital letter.
CaCl2( aq) K2CO3( aq) → 2KCl( aq) CaCO3( aq)
This equation tells us that 1 mole of CaCl2 will produce 2 moles of KCl.
If we want 10.0g of KCl, we need to convert that mass into moles KCl by dividing by the molar mass of KCl, which is 74.55 grams/mole.
(10.0 grams KCl)/(74.55 grams/mole) = 0.1341 moles of KCl.
We know that we'll need half that amount of moles CaCl2, since the balanced equation says we'll get twice the moles KCl for every one mole CaCl2.
So we'll need (0.1341 moles KCl)*(1 mole CaCl2/2moles KCl) = 0.0671 moles CaCl2.
The molar mass of CaCl2 is 110.98 grams/mole.
(0.0671 moles CaCl2)*(110.98 grams/mole) = 7.44 grams CaCl2
7.44 grams CaCl2 will produce 10.0 grams KCl.
