# Homework Help: Chemistry: Help with balancing

1. Oct 1, 2007

### Valseki

1. The problem statement, all variables and given/known data

Write and balance the reaction between aqueous calcium chloride and aqueous sodium carbonate. Write the net ionic reaction. If you start with 10.0g of calcium chloride and an excess of sodium carbonate, how many grams of precipitate will form?

2. Relevant equations

3. The attempt at a solution

$$CaCl_{2}_{(aq)} + Na_{2}CO_{3}_{(aq)} \rightarrow CaCO_{3}_{(aq)} + 2NaCl_{(s)}$$

This is what I get for a balanced reaction. From what I gather, this would be a double displacement and the sodium carbonate is precipitates out since carbonate has a low solubility. The other parts of this question I understand how to do as long as I am correct with this part. Is this reaction balanced or am I completely wrong? Thanks in advance!

2. Oct 1, 2007

### eli64

reaction is balanced but check your solubility table for CaCO3 and NaCl - what is the precipitate?

3. Oct 2, 2007

### Valseki

$$CaCl_{2}_{(aq)} + Na_{2}CO_{3}_{(aq)} \rightarrow CaCO_{3}_{(s)} + 2NaCl_{(aq)}$$

Is balanced with the correct precipitate.

The net ionic reaction is this:

$$Ca_{(aq)} + CO_{3}_{(aq)} \rightarrow CaCO_{3}_{(s)}$$

My problem is the next part, I can get the grams of the NaCO3 but I am confused on where to go from there.

4. Oct 2, 2007

### eli64

first don't forget charges for Ca and CO3 in your net ionic equation

you also don't need gms of Na2CO3

You need to find the mass of the ppt which is the thing with (s)

start wi,th the 10.0 grms of the calcium chloride, find moles calcium chloride, find moles of the ppt, then find grams of the ppt.

how do you find moles from grams and grams from moles (MM = g/mol)