chemistry homework help :molar relationship:reactants and products!?

Question

On a small scale, calcium can be isolated through the retion of calcium chloride with sodium metal
CaCl2 + 2Na --> Ca + 2NaCl
Question:
How many moles of Na are needed to react with 7.00 mol CaCl2?

Please help and could you please explain how to do it aswell

Answer 1

For this question you need to use the mole to mole ratios provided by the balanced chemical equation. By looking at the equation, for example, we can see that for every one mole of calcium chloride that is reacted with 2 moles of sodium, 1 mole of elemental calcium and 2 moles of sodium chloride are produced. In this question we are specifically concerned with CaCl2 and Na only. In what ratio do they combine/react? Look at the coefficients and see that it is one mole of CaCl2 to 2moles of Na. Write this relationship as a fraction and you get a conversion factor for use in solving your problem. Here are your possible conversion factors: (1molCaCl2/2molNa) or (2molNa/1mol CaCl2).

In solving this problem, you multiply the 7.00mol CaCl2 by whichever conversion factor gives you an answer in moles of Na. If you use the second one from above, the molCaCl2 will cancel out, leaving you with moles of Na . . .


7.00mol CaCl2 x(2molNa/1mol CaCl2) = 14 moles Na

Answer 2

1. Look at the equation.There are 2 moles of Na per mole of CaCl2. Now, have you done stochiometry? Multiply- 7.00 mols CaCl2 times (2 mols Na/ 1 mol cacl2). 14 moles is your answer.

Answer 3

Two Na per CaCl2 (from reaction equation)

So two moles Na for each mole CaCl2. That's all. No mystery!

Take it from there. Good luck!