1. Choose Your Category The MoleAverage Atomic Mass and Molar Mass FormulasPercentage Composition Limiting Reactants Percentage Yield and Error Vocab 100 200 300 400 500 The Final Question

2. The Mole - 100 The SI base unit used to measure the amount of a substance whose number of particles equals the number of atoms of carbon in exactly 12 grams of carbon-12 Back The Answer is the mole

3. The Mole - 200 The number of atoms in a mole of any pure substance is called Back The Answer is the Avogadro's number

4. The Mole - 300 What can be said about the atoms in 1 mol Ag and 1 mol Au? Back The Answer is they contain the same number of atoms.

5. The Mole - 400 The _______________ in a chemical equation represent the relative number of moles of reactants and products. Back The Answer is coefficients.

6. The Mole - 500 In the reaction N 2 + 3H 2  2NH 3, what is the mole ratio of nitrogen to ammonia? Back The Answer is 1 to 2

7. Average Atomic Mass and Molar Mass - 100 Using a periodic table, what is the average atomic mass of zinc? Back The Answer is 65.4 amu.

8. Average Atomic Mass and Molar Mass - 200 What is 120 g/mol in amu? Back The Answer is 120 amu.

9. Average Atomic Mass and Molar Mass - 300 The atomic mass of hydrogen is 1.008 amu. This is because there is more than one ____________ of hydrogen. Back The Answer is isotope.

10. Random Points 600 points

11. Average Atomic Mass and Molar Mass - 400 Calculate the molar mass of barium nitrate, Ba(NO 3 ) 2. Back The Answer is 261.35 g/mol.

12. Average Atomic Mass and Molar Mass - 500 Change 58 grams of water into moles. Back The Answer is 3.22 moles. (58g x 1mol/18 g)

13. Formulas - 100 A formula that shows the simplest whole- number ratio of the atoms in a compound is the ________________ ___________. Back The Answer is empirical formula.

14. Formulas - 200 The first step in finding the empirical formula from the percentage composition is to assume that you have this many grams? Back The Answer is 100 g.

15. Formulas - 300 A compound’s empirical formula is NO 2. If the formula mass is 92 amu, what is the molecular formula? Back The Answer is N 2 O 4

16. Random Points 500 points

17. Formulas - 400 A compound contain 79.85% carbon and 20.15 % hydrogen. What is the empirical formula? Back The Answer is CH 3

18. Formulas - 500 A compound contains 9.1 % hydrogen, 54.5 % carbon and 36.4 % oxygen. What is the molecular formula if its molar mass is132 amu? Back The Answer is H 12 C 6 O 3

19. Percentage Composition – 100 The percentage of sulfur in SO 2 is about 50%. What is the percentage of oxygen in this compound? Back The Answer is 50%.

20. Percentage Composition – 200 Calculate the percentage of sulfur in CuSO 4. Back The Answer is 20.09%.

21. Random Points 300 points

22. Percentage Composition – 300 What is the percentage composition of each element in CuCl 2 ? Back The Answer is 47.3% Cu, 52.7% Cl.

23. Percentage Composition – 400 What is the percentage composition of CF 4 ? Back The Answer is 13.6% C, 86.4% F

24. Daily Double

25. Percentage Composition – 500 What is the percentage composition of each element in (NH 4 ) 2 HPO 4 ? Back The Answer is 21.2% N, 6.8 % H, 23.5% P, and 48.5% O

26. Limiting Reactants - 100 To determine the limiting reactant in a chemical reaction, one must change each reactant into the ________ product with the ________ units. Back The Answer is same (and same).

27. Limiting Reactants - 200 A chemical reaction involving substances A and B stops when B is completely used. B is the ___________________. Back The Answer is limiting reactant

28. Limiting Reactants - 300 All the other reactants besides the limiting reactant are called ____________ reactants Back The Answer is excess.

29. Limiting Reactants - 400 The first step in most stoichiometry problems is to _____________. Back The Answer is convert given quantities to moles.

30. Random Points 800 points

31. Limiting Reactants - 500 If 2 moles of each reactant are available for the reaction described by the following equation, SiO 2 (s) + 3C(s)  SiC(s) + 2CO(g), determine which substance is the limiting reactant by calculating the moles of SiC each of the reactants can produced. Back The Answer is carbon.

32. Percentage Yield and Error - 100 Back The Answer is percentage yield What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?

33. Percentage Yield and Error - 200 Actual yield must be determined by __________________. Back The Answer is experiments.

34. Random Points 400 points

35. Percentage Yield and Error - 300 For the reaction CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g), calculate the percentage yield of carbon dioxide if 1000 g of methane (needed to calculate theoretical) react with excess oxygen to produce 2300 g of carbon dioxide (experimental). Back The Answer is 83.9%.

36. Percentage Yield and Error - 400 What is the percent of error in evaluating the molecular mass of a compound if the experimental value was 69.2 amu and the known value was 75.5 amu? Back The Answer is 8.3%

37. Random Points 400 points

38. Percentage Yield and Error - 500 For the reaction CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g), calculate the percentage error of carbon dioxide if 1000 g of methane (needed to calculate theoretical) react with excess oxygen to produce 2300 g of carbon dioxide (experimental). Back The Answer is 16.1%

39. Vocab - 100 The proportional relationship between two or more substances during a chemical reaction Back The Answer is stoichiometry

40. Vocab - 200 The mass in grams of 1 mol of a substance Back The Answer is the molar mass

41. Vocab - 300 The percentage by mass of each element in a compound Back The Answer is the percentage composition

42. Vocab - 400 The measured amount of a product of a reaction Back The Answer is actual yield

43. Vocab - 500 A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms Back The Answer is the molecular formula

44. The Final Question The final question has to deal with: »Stoichiometry Make your wager and hand it to the teacher

45. Stoichiometry How many molecules of hydrogen are produced if 20.0 g of sodium metal react with excess water according to the chemical equation: 2 Na(s) + 2 H 2 O(l)  2 NaOH(aq) + H 2 (g)?

46. And the Answer is: The Answer is 2.62 x 10 23 20.0 x (1 mol/23 g) = 0.87 mol Na x (1 mol H 2 /2 mol Na) = 0.435 mol H 2 x (6.02x10 23 molecules/1 mol) =