List all of the materials and equipment that Jeremy would have to use in his experiment.

1. Jeremy decides to make some Macaroni and Cheese from a box. He notices the directions ask him to add salt to water before bringing it to a boil. The next day, Jeremy asks his science teacher “How does adding salt to water affect the way it boils?” They plan an experiment to find out the answer. The following graph summarizes Jeremy’s findings. List all of the materials and equipment that Jeremy would have to use in his experiment.

2. Using Jeremy’s experiment, identify: 1. the independent variable. 2. the dependent variable. 3. the experimental control group. 4. Jeremy’s probable conclusion.

3. Which formula represents a molecular compound?(1) HI (3) KCl(2) KI (4) LiCl

4. Which type of matter is composed of two or more elements that are chemically combined in a fixed proportion?(1) solution(2) compound(3) homogeneous mixture(4) heterogeneous mixture

5. EX 1: Convert 1006051 to scientific notation. 1006051 The natural decimal point is here Decimal will move here 1.006051 x 106 6 because the decimal moved 6 times

6. Zn 2+ Determine the number of protons, neutrons, electrons, and the mass number 65 30

7. 30 protons, 35 neutrons, 28 electrons, mass number = 65

8. EX 2: Convert 0.0052300 to scientific notation. 0 0052300 The natural decimal point is here Decimal will move here 5.2300 x 10-3 Negative because the original number is less than 1 and 3 because the decimal moved 3 times

9. 1 EX: Determine the number of significant figures in a) 4 b) 4.0 c) 40 d) 0.0400 e) 4004 f) 0.0004 2 1 3 4 1

10. Practice EX 1: Determine the number of significant figures in: • 2 • 5.0 • 10 • 0.0400 • 8005 • 3.00 x 103 1 2 1 3 4 3

11. EX 2: Convert each of the values into scientific notation while retaining the same number of sig figs • 60000 • 20 • 4004 • 0.0900 6 x 104 2 x 101 4.004 x 103 9.00 x 10-2

12. Lets practice together… Round the following numbers to 3 sig figs a) 51.234 b) 51.38 c) 51.3587 d) 51,358 e) 0.050554 51.2 Or 5.12 x 101 Or 5.14 x 101 51.4 51.4 Or 5.14 x 101 51,400 Or 5.14 x 104 0.0506 Or 5.06 x 10-2

13. YOUR Practice • EX: Round the following numbers to 3 sig figs • 51.234 51.2 • 51.38 • 51.3587 • 51,358 • 0.050554 • 5,135,593 51.2 51.4 51.4 51,400 0.0506 5,140,000

14. Example: 2.8 1 2 3 4 5 6 7 8 9 10 It is expected that you will always report all sig figs on any laboratory reading!

15. Example: 2.71 1 2 3 4 5 6 7 8 9 10 It is expected that you will always report all sig figs on any laboratory reading!

16. Which Lewis electron-dot diagram representscalcium oxide?

17. Explain which of the following represent pure substances and which represent mixtures.

18. Practice • 22.101 mL – 0.9307 mL = • 2.5 g / 3.42 g = • 2.33 cm x 6.085 cm x 2.1 cm = • 23.1 in + 4.77 in + 125.39 in + 3.581 in = 21.170 mL 0.73 g 30. cm3 156.8 in

19. 47.5 mL • EX: 37.24 mL + 10.3 mL = • 27.87 g – 2.2342 g = 25.64 g

20. Ex. 37.24mL + 10.3 mL 47.54mL Reported as 47.5mL Rules for Math Operations with Significant Figures Addition and Subtraction

21. Ex. 27.87 g - 21.2342 g 6.6358 g Reported as 6.64g Rules for Math Operations with Significant Figures Addition and Subtraction

22. 2. Multiplication and Division • The measurement with the fewest sig figs determines the number of sig figs in the answer • EX: 12.34 cm X 0.23 cm = 2.8 cm2

23. Practice • 2. Determine the number of g in 0.03455 kg Relationship1000g = 1kg want given Start with what’s given 0.03455 kg 1000 g g = 34.6 1 1 kg

24. Relationships 1000 mL = 1L 1L = 1.06 quarts 1 quart = 4 cups given want • Ex. 2 Convert 323 mL to cups Start with what’s given 4 cups 1.06 qt. 323 mL 1 L 1 L 1000 mL 1 1 qt. cups = 1.37

25. Relationships 1 foot = 12 inches 2.54cm = 1 in 100 cm = 1 m 1 m = 1000 mm given want • Practice 1: Convert 7.005 ft to mm Start with what’s given 1000 mm 12 in 2.54 cm 1 m 7.005 ft 1 1 ft 1 in 100 cm 1 m = 2135 mm

26. Relationships1km = 1000m 1h = 60 min 1 min = 60 s given want • EX 1: Convert 0.083 km/h to m/s Start with what’s given 1000m 1 hr 1 min 0.083km 1hr 1 km 60 min 60 s m/s = 2.31 X 10-2

27. Relationships2.54 cm = 1 in • 12 in = 1 ft • 60 s = 1 min • 1 hr = 60 min want • 1. Convert 3.56 cm/s to ft/h given Start with what’s given 1 in 1 ft 60 s 60 min 3.56 cm 1 s 2.54 cm 12 in 1 min 1 hr = 420 ft/hr

28. Relationships$1 = 100 cents • 2.54 cm = 1 in • 12 in = 1 ft given want • 2. Convert $25.00/feet to cents/cm Start with what’s given 1 in 100 cents 1 ft $ 25.00 12 in 1 ft $1 2.54 cm = 82.0 cents/cm

29. Determine the number of centimeters in 1.76 kilometers(Show all dimensional analysis.)

30. Determine the number of inches in 697 mm.Note: 2.54 cm = 1 inch(Show all dimensional analysis.)

31. Determine the number of atoms in 5.20 moles of C6H12 . (Show all dimensional analysis.)

32. How many significant figures do the following numbers contain?A) 4,250.00B) 4040C) 0.009D) 325.08 E) 6.02 x 1023

33. Find the answer to the following using the correct number of significant figures. A) 4,250.38 + 25.1B) 4040 x 32

34. Read the following to the correct number of significant figures.

35. Which statement describes a chemical property of bromine?(1) Bromine is soluble in water.(2) Bromine has a reddish-brown color.(3) Bromine combines with aluminum to produce AlBr3.(4) Bromine changes from a liquid to a gas at 332 K and 1 atm.

36. An atom of aluminum in the ground state and an atom of gallium in the ground state have the same - (1) mass(2) electronegativity(3) total number of protons(4) total number of valence electrons

37. In an atom of argon-40, the number of protons – (1) equals the number of electrons(2) equals the number of neutrons(3) is less than the number of electrons(4) is greater than the number of electrons

38. Which type of substance can conduct electricity in the liquid phase but not in the solid phase?(1) ionic compound(2) molecular compound(3) metallic element(4) nonmetallic element

39. Why is a molecule of CO2 nonpolar even though the bonds between the carbon atom and the oxygen atoms are polar?(1) The shape of the CO2 molecule is symmetrical.(2) The shape of the CO2 molecule is asymmetrical.(3) The CO2 molecule has a deficiency of electrons.(4) The CO2 molecule has an excess of electrons.

40. The relatively high boiling point of water is due to water having- (1) hydrogen bonding(2) metallic bonding(3) nonpolar covalent bonding(4) strong ionic bonding

41. Matter is classified as a - (1) substance, only(2) substance or as a mixture of substances(3) homogenous mixture, only(4) homogenous mixture or as a heterogeneous mixture

42. Which substance can not be decomposed by a chemical change?(1) ammonia (3) propanol(2) copper (4) water

43. A beaker contains both alcohol and water. These liquids can be separated by distillationbecause the liquids have different(1) boiling points (3) particle sizes(2) densities (4) solubilities

44. A sample of an element is malleable and can conduct electricity. This element could be - (1) H (3) S(2) He (4) Sn

45. Identify the element in Period 3 of the Periodic Table that reacts with oxygen to forman ionic compound represented by the formula X2O.

46. Based on data collected during a laboratory investigation, a student determined anexperimental value of 322 joules per gram for the heat of fusion of H2O. Calculate thestudent’s percent error. Your response must include a correct numerical setup and thecalculated result.

47. Calculate the density of a 129.5-gram sample of bronze that has a volume of 14.8 cubiccentimeters. Your response must include a correct numerical setup and the calculatedresult. 8.75 g/cm3

48. Atomic Structure Questions Answers

49. Determine the number of protons, neutrons, and electrons in an ion of magnesium with a 2+ charge and a mass number of 25.

50. p+ = 12n0 = 13e- = 10