how many grams of barium chloride are needed to produce 4.35 grams of Ba?

Question

__Cu+__BaCl₂ = __Ba+__CuCl3

Answer 1

Step 1: Balance the equation

We have _Cu + _BaCl₂ --> _Ba + _CuCl₃. 

To balance out the chlorine, we would need to double the CuCl₃ and triple the BaCl₂, resulting in the following equation: 

_Cu + 3BaCl₂ --> _Ba + 2CuCl₃

Now, the Ba and Cu are no longer balanced! To do that, we would need to double the Cu and triple the Ba, resulting in the following equation: 

2Cu + 3BaCl₂ --> 3Ba + 2CuCl₃

Now the equation is balanced! 

Step 2: Convert grams Ba to moles Ba.

We do this using the molar mass! 

4.35 g Ba x 1 mol Ba/ 137.327g Ba = 0.0317 moles of Ba

Step 3: Convert moles Ba to moles BaCl₂

Now, following the balanced equation we know that 3 mol of Ba will be produced from 3 mol of BaCl₂. Since that means they combine in a 1 to 1 ratio, we know we need to have 0.0309 moles of BaCl₂

Step 4: Convert moles BaCl₂ to grams BaCl₂

0.0309 moles BaCl₂ x 208.23 g BaCl₂ /mol BaCl₂ = 6.60 g BaCl₂