PORTAGE LEARNING CHEM 121 MODULE 1 EXAM
QUESTIONS AND ANSWERS 2026/2027 | GRADED A+
| NEW UPDATE!!!
1. Convert 1005.3 to exponential form and explain your answer.
2. Convert 4.87 x 10-6 to ordinary form and explain your answer. - ANSWER--
Convert 1005.3 = larger than 1 = positive exponent, move decimal 3 places =
1.0053 x 103
2. Convert 4.87 x 10-6 =negative exponent =smaller than 1, move decimal 6 places
= 0.00000487
1. 350 pounds = ? ton
2. 0.632 m = ? cm - ANSWER--1. 350 pounds x 1 ton / 2000 pounds = 0.175 ton
2. 0.632 m x 100 cm / 1 m = 63.2 cm
1. 246 oK = ? oC
2. 45 oC = ? oF
3. 18 oF = ? oK - ANSWER--1. 246oK - 273 = -27 oC oK → oC (make smaller) -273
,2. 45oC x 1.8 + 32 = 113 oF oC →
oF (make larger) x 1.8 + 32
3. 18oF - 32 ÷ 1.8 = -7.8 + 273 =
265.2 oK oF → oC → oK
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. -
ANSWER--1. M = D x V = 1.49 x 18.6 = 27.7 g
2. D = M / V = 26..5 = 0.862 g/ml
1. 0.0756 contains ? significant figures.
2. 1.235 contains ? significant figures.
3. 0.0756 + 1.235 = ? (give answer to correct number of significant figures) -
ANSWER--1. 0.0756 contains 3 significant figures
2. 1.235 contains 4 significant figures
3. 0.0756 + 1.235 = 1.3106 = 1.311 (to the thousands place for 1.235)
, 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 - ANSWER--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
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 - ANSWER--31 protons = Ga31, 39 neutrons
= 70Ga31, 28 electrons = (+31 - 28 = +3) = 70Ga31+3
Name each of the following chemical compounds. Be sure to name all acids as
acids (NOT for instance as binary compounds)
1. PF5
QUESTIONS AND ANSWERS 2026/2027 | GRADED A+
| NEW UPDATE!!!
1. Convert 1005.3 to exponential form and explain your answer.
2. Convert 4.87 x 10-6 to ordinary form and explain your answer. - ANSWER--
Convert 1005.3 = larger than 1 = positive exponent, move decimal 3 places =
1.0053 x 103
2. Convert 4.87 x 10-6 =negative exponent =smaller than 1, move decimal 6 places
= 0.00000487
1. 350 pounds = ? ton
2. 0.632 m = ? cm - ANSWER--1. 350 pounds x 1 ton / 2000 pounds = 0.175 ton
2. 0.632 m x 100 cm / 1 m = 63.2 cm
1. 246 oK = ? oC
2. 45 oC = ? oF
3. 18 oF = ? oK - ANSWER--1. 246oK - 273 = -27 oC oK → oC (make smaller) -273
,2. 45oC x 1.8 + 32 = 113 oF oC →
oF (make larger) x 1.8 + 32
3. 18oF - 32 ÷ 1.8 = -7.8 + 273 =
265.2 oK oF → oC → oK
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. -
ANSWER--1. M = D x V = 1.49 x 18.6 = 27.7 g
2. D = M / V = 26..5 = 0.862 g/ml
1. 0.0756 contains ? significant figures.
2. 1.235 contains ? significant figures.
3. 0.0756 + 1.235 = ? (give answer to correct number of significant figures) -
ANSWER--1. 0.0756 contains 3 significant figures
2. 1.235 contains 4 significant figures
3. 0.0756 + 1.235 = 1.3106 = 1.311 (to the thousands place for 1.235)
, 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 - ANSWER--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
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 - ANSWER--31 protons = Ga31, 39 neutrons
= 70Ga31, 28 electrons = (+31 - 28 = +3) = 70Ga31+3
Name each of the following chemical compounds. Be sure to name all acids as
acids (NOT for instance as binary compounds)
1. PF5
