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Name ______________________Date _________________ Midterm Review Section A B C
Unit 1 - Thinking Like a Scientist
1. Fast forward ten years, and Andrew McCrady is a world famous chemist researching the formation of water. He reacts 10 grams of hydrogen with 10 grams of oxygen and finds the mass of water formed. Then, he reacts 20 grams of hydrogen with 10 grams of oxygen, and finds the mass of water formed. Finally, he reacts 30 grams of hydrogen with 10 grams of oxygen and finds the mass of water formed. The data collected is shown below:
Mass of hydrogen (g) Mass of oxygen (g) Mass of water formed (g)10 10 11.2620 10 11.2630 10 11.26
a. What is a possible research question for this experiment?
b. Write a possible hypothesis for this experiment.
c. List the variables below:
i. independent variable:
ii. dependent variable:
iii. control(s)
d. Was your hypothesis (from question part b) supported by Andrew’s data? Why or why not?
e. BONUS: Make a hypothesis that explains why the mass of water formed did not change as the mass of hydrogen was increased.
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Unit 1 – Matter
2. Are the following examples matter or not matter?
a. Air ____________________ d. atoms ____________________
b. Wind ____________________ e. love ____________________
c. Electricity ____________________ f. water ____________________
3. What is chemistry?
4. What are the three states of matter and what are two properties of each state?
a. .
b. .
c. .
5. How does the kinetic energy of each state of matter compare?
6. Draw a diagram showing the names of all six transitions between states of matter. Then, choose three transitions and give an example of each.
Page 2 of 14
7. For each of the following properties, write whether it is intensive or extensive
a. Mass ___________________________ d. shape ___________________________
b. Length ___________________________ e. density ___________________________
c. Color ___________________________
8. Are the following physical changes or chemical changes?
a. Burning ___________________________ e. freezing __________________________
b. reacting___________________________ f. digesting food _____________________
c. folding paper___________________________
9. Are the following mixtures or pure substances?
a. Sand ___________________________ e. air ___________________________
b. Salt ___________________________ f. gold ___________________________
c. Water ___________________________ g. carbon dioxide ___________________
d. Chocolate chip cookies ___________________________
10. What is the smallest unit of matter? ________________________
11. What is a compound? Give an example.
12. What is a mixture? Give an example.
13. Write a brief procedure to separate a mixture of iron filings, sand and salt.
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14. What classification of matter can be physically separated and is unevenly mixed (not uniform)?
15. What classifications of matter can not be physically separated?
16. What classification of matter can be chemically separated but not physically separated?
17. In which classification of matter are two or more elements chemically combined and form a new substance with its own properties?
18. In which classification of matter are two or more substances physically combined and retain their own properties?
19. What classification are the following samples of matter? (homogeneous mixture, heterogeneous mixture, compound, element – each one used twice)
a. Chocolate ice cream _______________________
b. Chocolate Chip ice cream _______________________
c. Chicken noodle soup _______________________
d. Tomato soup _______________________
e. Water (H20) _______________________
f. Gold _______________________
g. Oxygen _______________________
h. Salt (sodium chloride) _______________________
Unit 1 – Measurements and Calculations20. What is the difference between precision and accuracy?
21. What is density? What is the equation for density?
Page 4 of 14
22. Calculate the density of a block of metal that has dimensions of 1.0 cm by 2.0 cm by 1.5 cm and a mass of 6.0 grams. Will the block float or sink in water? Why?
23. Use dimensional analysis to solve the following problems. Show all your work, and round your answer to the correct number of significant figures. (1000 mL = 1 L, 100cL = 1L, 1000L = 1 kL)
a. How many kilometers are in 32 meters?
b. How many milligrams are in 590 grams?
c. How many centiliters are in 27 kiloliters?
d. How many kilograms are in 456 miligrams?
e. How many centimeters are equal to 10.0 inches? (1 inch = 2.54 centimeters)
24. Complete the following table:
Unit What it measures abbreviation Tool used to measure it
Liter Graduated cylinder
length
Gram g
Page 5 of 14
Unit 2 - Atomic Theory
25. Fill in the following table:Subatomic Particle Charge Location Mass
26. Complete the following table.Element name Symbol Atomic number # of Protons # of Electrons
Oxygen
S
36
Unit 2 - Ions and Compounds27. For the element oxygen, draw a diagram of the atom with the nucleus and electrons, circle the
valence shell, and write the symbol of the ion formed.
28. Fill in the following table:Element Group
NumberNumber of valence electrons
Does it gain or lose electrons?
How many does it gain or lose?
Charge of Ion
Symbol of Ion
Name of Ion
Sodium
Fluorine
Magnesium
Sulfur
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29. On the periodic table below, where are the metals? Where are the non-metals?
30. Explain the octet rule and how it determines the ways elements will form bonds
31. Describe what happens in an ionic bond.
32. Describe what happens in a covalent bond.
33. Draw Lewis Dot Structures for the following covalent compounds:
a. Cl2 d. NH3
b. S2 e. H2O
Page 7 of 14
Unit 2 – Naming and Formula writing
34. Write names for the following compounds AND state whether it is ionic or covalent: (REMEMBER –
the system for naming compounds depends on whether the compound is ionic or covalent)
a. BeF2
b. PbI2
c. FeCO3
d. CuCl2
e. Sn(SO3)2
f. N2O
g. CCl4
h. NO
i. NO2
j. N2O3
35. Write formulae for the following compounds.
a. calcium fluoride
b. rubidium sulfate
c. tin (IV) hydroxide
d. lead (II) chlorate
e. dihydrogen monoxide
f. phosphorus trichloride
g. dinitrogen tribromide
h. phosphorus pentachloride
Page 8 of 14
Unit 3 – Introduction to Stoichiometry
36. What is a mole? How many atoms or molecules are there in a mole?
37. How many atoms of chlorine are there in 5.00 moles of nitrogen?
38. Calculate the mass of 1.25 moles of chlorine.
39. How many moles of carbon dioxide are equal to 5.00x1025 molecules of carbon dioxide?
40. Calculate the mass of 1.25 moles of carbon dioxide.
41. How many atoms are equal to 5.00 grams of chlorine?
42. Calculate the mass of 5.00x1028 molecules of carbon dioxide.
43. Calculate the mass of 4.51x1024 molecules of calcium chloride.
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Unit 3 – Formulas and Composition of Compounds
44. Calculate the percent by mass (to 2 decimal places) of both elements in calcium chloride.
45. What is the empirical formula for H2O2? ____________ C12H22O6? ______________ H2O? __________
46. Calculate the molecular formula of C2H3O, which has a molar mass of 172 g/mol.
47. Calculate the molecular formula of NO2, if the molar mass = 92.02 g/mol
48. Caffeine is 49.5% carbon, 5.2% hydrogen, 28.9% nitrogen and 16.5% oxygen by mass. Its molarmass is about 194.2 g/mol. Calculate the empirical and molecular formulae for caffeine.
Page 10 of 14
Unit 4 – Writing and Balancing Chemical Reactions
49. In a chemical equation, what do each of the following symbols mean?
a. +
b.
c. (s)
d. (g)
e. (aq)
50. Write the word equation for the following formula equation:BeCl2(s) + AgNO3(aq) Be(NO3)2(aq) + AgCl(s)
51. In the equation above, what are the reactants?
What are the products?
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52. Balance the following equations:
a. ____Fe(s) + ____H2SO4(aq) ____Fe2(SO4)3(aq) + ____H2(g)
b. ____BF3(g) + ____Li2SO3(aq) ____B2(SO3)3(aq) + ____LiF(aq)
53. Write and balance the formula equation for the following word equation:Solid iron (III) oxide reacts with a solution of sulfuric acid (H2SO4) to produce a solution of iron (III) sulfate and liquid water.
54. Write and balance the formula equation for the following reaction:Solutions of barium fluoride and potassium phosphate react to produce solid barium phosphate and a solution of potassium fluoride.
Page 12 of 14
Unit 4 – Types of Reactions
55. What type of reaction is each of these?
a. 2C6H6(l) + 15O2(g) 12CO2(g) + 6H2O(g)
b. H2(g) + Cl2(g) HCl(g)
c. Al(s) + ZnCl2(aq) Zn(s) + AlCl3(aq)
d. KClO3 KCl + KClO4
e. FeS(s) + HCl(aq) FeCl2(aq) + H2S(g)
Unit 4 – Reaction Stoichiometry
2Na3PO4 (aq) + 3CaCl2 (aq) 6NaCl (aq) + Ca3(PO4)2(s)
56. How many moles of Sodium Phosphate are in the reaction? ______________
How many moles of Sodium Chloride are in the reaction? ______________
What is the mole ratio of Sodium Phosphate to Sodium Chloride in the reaction? _________________
What is the mole ratio of Calcium Chloride to Calcium Phosphate in the reaction? _________________
57. How many moles of calcium chloride react with 2.00 moles of sodium phosphate?
58. How many moles of sodium chloride are produced by the reaction of 10.0 moles of sodium phosphate in excess calcium chloride?
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2Na3PO4 (aq) + 3CaCl2 (aq) 6NaCl (aq) + Ca3(PO4)2(s)
59. How many grams of calcium phosphate are produced by the reaction of 10.0 grams of sodium phosphate in excess calcium chloride?
60. If 3.1 moles of Sodium Phosphate react with 6.9 moles of Calcium Chloride, calculate the limiting reagent.
61. If 5.0 grams of sodium phosphate are reacted with 5.0 grams of calcium chloride, calculate the limiting reagent.
62. How many grams of calcium phosphate are produced by this reaction?
63. How many grams of the excess reagent are left over?
64. You calculated that 10.0 grams of NaCl should have been produced, but during your experiment, only 8.7 grams were produced. What was the percent yield of your experiment?
Page 14 of 14