1. MIDTERM REVIEW
Please get out: Paper, pencil, calculator and all chemistry knowledge 

2. Would freezing liquid mercury be considered a physical or chemical change?
Qualitative measurement

3. physical

4. Would dissolving sodium chloride in water be considered a physical or chemical change?
Error

5. physical

6. What are the two categories of pure substances?
Good precision, poor accuracy

7. Elements and compounds

8. How can an element be further separated
How can an element be further separated? By ordinary physical means; By ordinary chemical means; Or it cannot be further separated by ordinary physical or chemical means.
kilogram

9. Cannot be separated by ordinary physical or chemical means

10. As what type of matter would you classify vinegar (acetic acid in water)?
SI= m^3, non-SI= L

11. Homogeneous mixture

12. At one point in the school year, our room was a comfortable 85°F
At one point in the school year, our room was a comfortable 85°F. Is this observation qualitative or quantitative?
2.5 x 10^3

13. quantitative

14. A group of measurements that closely agree with one another but are far from the “true” value are said to be…
5.9 x 10^-6

15. precise

16. How many sig figs are in the following measurement:
40,600

17. 6 sf

18. Object A has a mass of 15. 2 g and a volume of 3. 6 mL
Object A has a mass of 15.2 g and a volume of 3.6 mL. Object B has a volume of 4.1 mL and a mass of 16.8 g. Which will sink first in water?
0.073

19. Object A (4.22g/mL vs. B= 4.10g/mL

20. You are in the lab and need to mix hydrochloric acid and water
You are in the lab and need to mix hydrochloric acid and water. In what order should you do this?
3.0 x 10^6

21. Pour acid into water

22. Which subatomic particle has a mass so small that it is considered negligible when finding mass number?
8 sfs

23. electron

24. An unknown element has 38 protons, 36 electrons, and 50 neutrons
An unknown element has 38 protons, 36 electrons, and 50 neutrons. Identify the element.
4 sfs

25. Always use protons for identity Strontium (*Sr2+)

26. Isotopes occur when atoms of the same element have different mass numbers. Therefore, an isotope has the same # of ______, but a different # of ______.
2 sfs

27. Same = protons
Different = neutrons

28. An atom has an atomic # of 31 and a mass # of 70
An atom has an atomic # of 31 and a mass # of 70. How many protons, electrons, and neutrons does the atom have?
5 sfs

29. Protons = 31
Electrons = 31
Neutrons = 39

30. What family has an electron configuration that ends in p5?
1500 cg

31. Halogens

32. What is the Noble Gas configuration for Selenium (Se)?
21 daL

33. [Ar]4s23d104p4

34. How many electrons can be held in each energy level
(n=1-4) of the atom?
98 dm

35. n = 1  2e- (s)
n = 2  8e- (s, p)
n = 3  18e- (s, p, d)
n = 4  32e- (s, p, d, f)

36. Do metals generally form cations or anions?
348 K

37. cations

38. Give the group and period trend for atomic radius.
52.63

39. Decreases across a period, increases down a column.

40. What type of elements tend to form covalent/molecular bonds?

41. 2 nonmetals

42. According to VSEPR theory, what is the molecular geometry of the compound silicon tetrachloride?

43. Tetrahedral

44. What type of bond is likely to form between two atoms with the same electronegativity value?

45. A nonpolar covalent bond

46. When comparing single, double and triple covalent bonds, a single covalent bond has the (shortest/longest) bond length and the (strongest/weakest) bond strength.

47. Longest – bond length weakest – bond strength
Single Covalent Bond
Longest – bond length weakest – bond strength

48. What is the correct name for
Mn(C2H3O2)4?

49. Manganese (IV) acetate

50. What is the correct name for C3H8?

51. Tricarbon octahydride

52. What is the correct formula for ammonium sulfite?

53. (NH4)2SO3

54. A compound contains 47. 0% K, 14. 5% C, and 38. 5 % O
A compound contains 47.0% K, 14.5% C, and 38.5 % O. Its molecular weight is g/mol. What is its molecular formula?

55. K2C2O4

56. If aqueous solutions of strontium chloride and sodium sulfate are mixed together, will a precipitate form?

57. Yes, strontium sulfate is insoluble (s)

58. What do we call the ions that appear in identical forms among both the reactants and products of a complete ionic equation that are not written in the net ionic equation?

59. Spectator ions

60. Classify and balance the reaction below:
__ K3PO4 + __CdCl2  __KCl + __Cd3(PO4)2

61. Double Replacement
2 K3PO4 + 3 CdCl2  6 KCl + 1 Cd3(PO4)2

62. In the balanced combustion reaction of ethane (C2H6), oxygen has the stoichiometric coefficient of ____.

63. Seven
2 C2H6 + 7 O2  4 CO2 + 3 H2O

64. What is the molar mass of magnesium nitrate?

65. Mg(NO3)2 = g/mol

66. How many moles of pyridine (C5H5N) are contained in 3.13g of pyridine?

67. moles

68. In an experiment, a 0. 33 mole sample of N2 reacts completely
In an experiment, a 0.33 mole sample of N2 reacts completely. What is the mass of Mg consumed in the reaction?
3 Mg + N2  Mg3N2

69. 24.07 g Mg

70. Mg (s) + 2 H2O (l)  Mg(OH)2 (s) + H2 (g)
In an experiment, the reaction of 4.73g of Mg with 1.83g of H2O actually produced 0.095g of H2. What is the percent yield of this reaction?
Mg (s) + 2 H2O (l)  Mg(OH)2 (s) + H2 (g)

71. 92.23% yield