The formulae and steps we used to find the weight of 0.126 mol of Sodium Carbonate were:

1. Find the weight of Na2CO3 (23*2) + 12 + (16 * 3)= 106 g/mol
2. Multiply the mol by our g/mol (0.126 mol of Na2CO3 *106 g /1mol = 13.30 grams)
3. Weigh them out and zero out the weigh boat

Using all of these steps we were able to conclude that the weight of 0.126 mol of sodium carbonate is 13.3 grams.