CHEM 103 MODULE 1 TO 6 EXAM ANSWERS
PORTAGE LEARNING GRADED A+
Question 1
... [Show More] Click this link to access the Periodic Table. This may be helpful throughout the exam.
1. Convert 845.3 to exponential form and explain your answer.
2. Convert 3.21 x 10-5 to ordinary form and explain your answer.
1. Convert 845.3 = larger than 1 = positive exponent, move decimal 2 places
= 8.453 x 102
2. Convert 3.21 x 10-5 = negative exponent = smaller than 1, move decimal 5 places = 0.0000321
Question 2
Using the following information, do the conversions shown below, showing all work:
1 ft = 12 inches 1 pound = 16 oz 1 gallon = 4 quarts
1 mile = 5280 feet 1 ton = 2000 pounds 1 quart = 2 pints
kilo (= 1000) 1/100) milli (= 1/1000) deci (= 1/10) centi (=
1. 24.6 grams = ? kg
2. 6.3 ft = ? inches
1. 24.6 grams x 1 kg / 1000 g = 0.0246 kg
2. 6.3 ft x 12 in / 1 ft = 75.6 inches
please always use the correct units in your final answer
Question 3
Do the conversions shown below, showing all work:
1. 28oC = ? oK 2. 158oF = ? oC 3. 343oK = ? oF
1. 28oC + 273 = 301 oK oC → oK (make larger)
+273
2. 158oF - 32 ÷ 1.8 = 70 oC oF → oC (make smaller)
-32 ÷1.8
3. 343oK - 273 = 70 oC x 1.8 + 32 = 158 oF oK → oC → oF
Question 4
Be sure to show the correct number of significant figures in each calculation.
1. Show the calculation of the mass of a 18.6 ml sample of freon with density of 1.49 g/ml
2. Show the calculation of the density of crude oil if 26.3 g occupies 30.5 ml.
1. M = D x V = 1.49 x 18.6 = 27.7 g
2. D = M / V = 26.3 / 30.5 = 0.862 g/ml
Question 5
1. 3.0600 contains ? significant figures.
2. 0.0151 contains ? significant figures.
3. 3.0600 ÷ 0.0151 = ? (give answer to correct number of significant figures)
1. 3.0600 contains 5 significant figures.
2. 0.0151 contains 3 significant figures.
3. 3.0600 ÷ 0.0151 = 202.649 = 203 (to 3 significant figures for 0.0151)
Question 6
Classify each of the following as an element, compound, solution or heterogeneous mixture and explain your answer.
1. Coca cola
2. Calcium
3. Chili
1. Coca cola - is not on periodic table (not element) - no element names (not compound)
appears to be one substance = Solution
2. Calcium - is on periodic table = Element
3. Chili - is not on periodic table (not element) - no element names (not compound)
appears as more than one substance (meat, beans,
sauce) = Hetero Mix
Question 7
Classify each of the following as a chemical change or a physical change
1. Charcoal burns
2. Mixing cake batter with water
3. Baking the batter to a cake
1. Charcoal burns - burning always = chemical change
2. Mixing cake batter with water - mixing = physical change
3. Baking the batter to a cake - baking converts batter to new material = chemical change
Click this link to access the Periodic Table. This may be helpful throughout the exam.
Show the full Nuclear symbol including any + or - charge (n), the atomic number (y), the mass number (x) and the correct element symbol (Z) for each element for which the protons, neutrons and electrons are shown - symbol should appear as follows: xZy+/- n
31 protons, 39 neutrons, 28 electrons
31 protons = Ga31, 39 neutrons = 70Ga31, 28 electrons = (+31 - 28 = +3)
= 70Ga +3
Question 9
Name each of the following chemical compounds. Be sure to name all acids as acids (NOT for instance as binary compounds)
1. PF5
2. Al2(CO3)3
3. H2CrO4
1. PF5 - binary molecular = phosphorus pentafluoride
2. Al2(CO3)3 - nonbinary ionic = aluminum carbonate
3. H2CrO4 - nonbinary acid = chromic acid incorrect fluoride prefix
Question 10
Write the formula for each of the following chemical compounds explaining the answer with appropriate charges and/or prefixes and/or suffixes.
1. Carbon monoxide
2. Manganese (IV) acetate
3. Phosphorous acid
1. Carbon monoxide - ide = binary, mono = 1 O = CO
2. Manganese (IV) acetate - Mn+4, C2H3O -1 = Mn(C2H3O2)4
3. Phosphorous acid - nonbinary acid of H + phosphite (PO -3) = H PO [Show Less]