1. 1.Carbon monoxide= CO, carbon dioxide= CO 2 2.When there is insufficient oxygen 3.CO; it binds strongly to hemoglobin interfering with oxygen transport in blood 4.N 2 O vs. NO 2, H 2 O vs. H 2 O 2 5.Definite proportions: a compound contains the same elements in the same ratio by mass Conservation of mass: in a chemical reaction matter is neither created nor destroyed 6.According to the law of conservation of mass the mass should remain unchanged 7.% girls = 12/28 x 100 = 42.86% % boys = 16/28 x 100 = 57.14% (or subtract)

2. %Mg in MgO = 8.CO = 12 +16 = 28 (no units) CO 2 = 12 + 16 + 16 = 44 9.CO: 43% C (12/28) and 57% O (16/28) CO 2 = 27% C (12/44) and 73% O (32/44) 10.Oxygen: Mg + O 2 MgO mass Mg mass MgO = 0.09 0.15 = 0.60 or 60% 12. %Mg in MgO = mass Mg mass MgO = 24.3 40.3 = 0.60 or 60% 11. 13.LCM is not disproved – container not sealed LDP not disproved – inadequate repetition and accuracy

3. Answers 13.Answers will vary from group to group E.g.: mass of Mg = 0.08, MgO = 0.13 % Mg = 0.08 / 0.13 = 62% Mg 14.Hopefully theyre close; the class average is. 15.Class results agree with the law of definite proportions (within experimental variation) The law of conservation of mass is still true (its a law after all). The mass in the crucible increased but thats only because it wasnt sealed. If the room had been sealed the mass of the room would not have changed. For more lessons, visit www.chalkbored.com www.chalkbored.com