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Introduction to Chemistry Final Worksheet Key, Exercises of Chemistry

Chem 105 at HCC worksheet and answer key. Exercise problems and solutions for introductory chemistry course.

Typology: Exercises

2020/2021

Uploaded on 04/20/2021

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CHEM 1405 Practice Comprehensive Final Exam and Answer Keys.
Corwin’s Introductory Chemistry
PART I Multiple choice (3 points each).
Do NOT mark on the test. Write your name and answers in Scantron.
1. Round off the following measurement to the four significant digits: 107.300 g
A) 107 g B) 107.0 g C) 107.3 g D) 107.5 g
2. Add 7.7 g to 51.65 g and round off the sum to the proper significant digits
A) 59.0 g B) 59.4 g C) 59.43 g D) 59.44 g
3. Express 0.000000000010 as an exponential number.
A) 1.0 X 1010 B) 1.0 X 1012 C) 1.0 X 1011 D) 1.0 X 1012
4. Which of the following unit factors is derived from: 1 foot = 12 inches?
A) 12 feet/ 12 inches B) 12 inches/ 12 feet C) 1 foot/ 12 inches D) 1760 yard/ 1 mile
5. The radius of a tin atom is 1.41 X 108 cm. What is the radius in meters? Given 1m = 102 cm
A) 1.41 X 1016m B) 1.41 X 1010m C) 1.41 X 104m D) 1.41 X 101m
6. A glass cylinder contains four separate liquid layers: chloroform (d = 1.49 g/mL), acetic acid (d
= 1.05 g/mL), ether (d = 0.708 g/mL). If a stone (d = 1.30 g/mL) is added to the cylinder, where
does it come to rest?
A) On bottom of the chloroform layer B) On top of chloroform layer
C) On top of acetic acid layer D) On the top of ether layer
7. How much energy is released when a 50.0 g sample of solid aluminum was cooled from
100.0°C to 60.0°C. The specific heat of the metal is 0.210 cal/(g°C).
A) 168.0 calories B) 210.0 calories C) 840.0 calories D) 420.0 calories
8. What is the equivalent temperature, in Kelvin, for 103°C?
A) 367 K B) 179 K C) 94 K D) 170 K
9. Which of the following elements is an example of a semimetal?
A) He B) Ca C) Cr D) Si
10. Use the periodic table and predict which of the following elements a liquid at 25°C.
A) Bi B) S C) Hg D) Ar
11. How many neutrons are in the nucleus of one atom of sulfur31?
A) 15 B) 16 C) 18 D) 31
12. What is the maximum number of electrons that can occupy a 3p sublevel?
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CHEM 1405 Practice Comprehensive Final Exam and Answer Keys. Corwin ’s Introductory Chemistry

PART I – Multiple choice (3 points each). Do NOT mark on the test. Write your name and answers in Scantron.

  1. Round off the following measurement to the four significant digits: 107.300 g A) 107 g B) 107.0 g C) 107.3 g D) 107.5 g
  2. Add 7.7 g to 51.65 g and round off the sum to the proper significant digits A) 59.0 g B) 59.4 g C) 59.43 g D) 59.44 g
  3. Express 0.000000000010 as an exponential number. A) 1.0 X 10 –^10 B) 1.0 X 10 –^12 C) 1.0 X 10 ^11 D) 1.0 X 1012
  4. Which of the following unit factors is derived from: 1 foot = 12 inches? A) 12 feet/ 12 inches B) 12 inches/ 12 feet C) 1 foot/ 12 inches D) 1760 yard/ 1 mile
  5. The radius of a tin atom is 1.41 X 10 –^8 cm. What is the radius in meters? Given 1m = 10^2 cm A) 1.41 X 10 –^16 m B) 1.41 X 10 ^10 m C) 1.41 X 10 –^4 m D) 1.41 X 10 –^1 m
  6. A glass cylinder contains four separate liquid layers: chloroform (d = 1.49 g/mL), acetic acid (d = 1.05 g/mL), ether (d = 0.708 g/mL). If a stone (d = 1.30 g/mL) is added to the cylinder, where does it come to rest? A) On bottom of the chloroform layer B) On top of chloroform layer C) On top of acetic acid layer D) On the top of ether layer
  7. How much energy is released when a 50.0 g sample of solid aluminum was cooled from 100.0°C to 60.0°C. The specific heat of the metal is 0.210 cal/(g°C). A) 168.0 calories B) 210.0 calories C) 840.0 calories D) 420.0 calories
  8. What is the equivalent temperature, in Kelvin, for – 103°C? A) – 367 K B) – 179 K C) – 94 K D) 170 K
  9. Which of the following elements is an example of a semimetal? A) He B) Ca C) Cr D) Si
  10. Use the periodic table and predict which of the following elements a liquid at 25°C. A) Bi B) S C) Hg D) Ar
  11. How many neutrons are in the nucleus of one atom of sulfur–31? A) 15 B) 16 C) 18 D) 31
  12. What is the maximum number of electrons that can occupy a 3p sublevel?

A) 2 B) 6 C) 10 D) 14

  1. What is the electron configuration for a copper (I) ion, Cu+^? A) [Ar] B) [Ar] 4s^2 3d^9 C) [Ar] 4s^1 3d^10 D) [Ar] 4s^0 3d^10
  2. NO 2 is classified as which of the following? A) Binary ionic B) Ternary ionic C) Binary molecular D) Ternary molecular
  3. What is the formula for the ionic compound composed of calcium ion, Ca2+^ and OH–^? A) CaOH B) CaOH 3 C) Ca 3 OH D) Ca(OH) 2
  4. What are the products from the following decomposition reaction? CaCO 3 (s) → A) Ca and CO 2 B) CaO and CO 2 C) Ca 2 O 3 and CO 2 D) CaO, H 2 O, and CO 2
  5. How many carbon dioxide molecules, CO 2 , have a mass of 22.0 g? A) 1.20 X 1023 molecules B) 1.20 X 1024 molecules C) 1.93 X 10 –^24 molecules D) 3.01 X 1023 molecules
  6. If 0.5 mol of krypton gas exerts a pressure of 1.00 atm at 100°C, what is the volume of the gas? (R = 0.08206 L atm./ mol K) A) 7.6 L B) 10.2 L C) 15.3 L D) 30.6 L
  7. How many valence electrons are in an oxygen atom and an oxide ion? A) 1 and 6, respectively B) 2 and 8, respectively C) 6 and 8, respectively D) 6 and 10, respectively.
  8. Which of the following ions does not have the following electron configuration? 1s^2 2s^2 2p^6 3s^2 3p^6? A) Cl–^ B) S^2 –^ C) K+^ D) Sr2+
  9. Given the electronegativity values H = 2.1, N = 3.0, O = 3.5, P = 2.1, and Cl = 3.0. Which of the following molecules contains polar covalent bonds? A) O 2 B) HCl C) PH 3 D) N-Cl bond
  10. Which molecule contains hydrogen bond? A) CO 2 B) NaCl C) HF D) H 2
  11. What are the products from the complete combustion of a hydrocarbon? A) Carbon dioxide and water B) Carbon monoxide and hydrogen C) Carbon monoxide and water D) Carbon dioxide and hydrogen
  12. What is the systematic name for for MgSO 4 •7H 2 O? A) Magnesium (II) sulfite heptahydrate B) Magnesium sulfite heptahydrate
  1. Calculate the heat required to convert 10.0 g of water from 20.0°C to 90.0°C. The specific heat of water is 1.00 cal/(g°C).

Answer q = 10.0x1.00x(90-20) = 700 joules

  1. If 10 moles of butane are combusted according to the following reaction,

2 C 4 H 10 (g) + 13 O 2 (g) → 8 CO 2 (g) + 10 H 2 O (g)

how many moles of water will be formed?

Answer: 10 moles C 4 H 10 (g) x 10 moles H 2 O (g) 2 moles C 4 H 10 (g) = 10x 2 = 50 moles H 2 O (g)

  1. Dioxane, a common solvent for plastics, is 54.5 % C, 9.15 % H, and 36.3 % O by mass. What is the empirical formula of dioxane?

Answer: Mole C : mole H: mole O = 54.5/12 : 9.15/1.008 : 36.3/16 = 4.54 : 9.15 : 2.27 = 4.54/2.27 : 9.15/2.27 : 2.27/2.27 = 2 : 4 : 1 Thus, the empirical formula is C 2 H 4 O.