A chemical change is a change in composition resulting in a product with different properties.  True  False

A chemical reaction was used to produce 1.61 moles of copper (II) bicarbonate, Cu(HCO3)2. What mass of copper (II) bicarbonate was produced? _?_g

You can also calculate percent composition from a formula. This is similar to percent abundance in that what percentage of a compound is each element. If you look at the compound and tell how many of each element there is, you calculate the percent composition.  Ex. Calculate the total mass of a compound just like before - CO2 C = 1 X 12 = 12g O = 2 X 16 = 32g 12+32 = 44g Then take the mass of each and divide by the total. 12/44 X100 = 27% carbon 32/44 X 100 = 73% oxygen  CO2 is 27% carbon and 73% oxygen. What percentage of Na3PO4 is sodium (Na)?

6. You are working in the laboratory, preparing sodium chloride. Consider the following results for three preparations of the compound. Case 1: 39.34 g Na + 60.66 g Cl2 → 100.00 g NaCl Case 2: 39.34 g Na + 70.00 g Cl₂ → 100.00 g NaCl + 9.34 g Cl2 Case 3: 50.00 g Na + 50.00 g Cl₂ →100.00 g NaCl + 17.57 g Na Explain these results in terms of laws of conservation of mass and definite composition.