## Get All Week Introduction to Chemistry: Reactions and Ratios Quiz Answers

## Table of Contents

### Introduction to Chemistry: Reactions and Ratios Week 01 Quiz Answers

#### Math Concept Quiz

Q1. One mole of C_2H_6O*C*2*H*6*O* has two moles of Carbon (C), six moles of Hydrogen (H) and one mole of Oxygen (O). How many moles of Hydrogen is in 0.2 moles of C_2H_6O*C*2*H*6*O*?

**Answer:** **To find out how many moles of hydrogen (H) are in 0.2 moles of C₂H₆O (C2H6O), we can use the mole ratio from the chemical formula of C₂H₆O, which is C₂H₆O. The mole ratio for hydrogen in C₂H₆O is 6 moles of H for every 1 mole of C₂H₆O.**

**So, for every 1 mole of C₂H₆O, there are 6 moles of H. Therefore, for 0.2 moles of C₂H₆O, you would have:**

**0.2 moles C₂H₆O × 6 moles H/mole C₂H₆O = 1.2 moles H**

**So, there are 1.2 moles of hydrogen in 0.2 moles of C₂H₆O.**

Q2. The team manager mixes 0.6 kg of Gatorade powder with water in the 5-gallon water coolers for the football team. Gatorade donates new 7-gallon water jugs. How much powder should the manager use in a new 7-gallon cooler to maintain the same Gatorade mixture? (in kg)

**Answer: To maintain the same Gatorade mixture, you need to maintain the same ratio of Gatorade powder to water. The initial mixture contains 0.6 kg of Gatorade powder in a 5-gallon cooler. To find the ratio of powder to water, you can calculate the ratio of powder to the total mixture:**

**Ratio of powder to mixture = (0.6 kg) / (5 gallons)**

**Now, you want to use a 7-gallon cooler while maintaining the same ratio. Let x be the amount of powder (in kg) needed for the 7-gallon cooler. The ratio in the new cooler should still be the same:**

**x kg / 7 gallons = (0.6 kg) / (5 gallons)**

**Now, solve for x:**

**x = (0.6 kg / 5 gallons) * 7 gallons x = 0.84 kg**

**So, the manager should use 0.84 kg of powder in the new 7-gallon cooler to maintain the same Gatorade mixture.**

Q3. Solve the following equation for x.

\frac{6}{x}*x*6 = \frac{10}{7}710.

x = _______.

**Answer: ** **To solve the equation 6�=107 x6=710 for x, you can cross-multiply and then solve for x:**

**6�=107 x6=710**

**Cross-multiply:**

**7 * 6 = 10 * x**

**42 = 10x**

**Now, divide both sides by 10 to isolate x:**

**x = 42 / 10**

**x = 4.2**

**So, the solution to the equation is �=4.2 x=4.2.**

Q4. If the volume of a spherical droplet is V = \frac{4}{3} \pi r^3*V*=34*πr*3 and the diameter of the droplet is twice the radius, d = 2r*d*=2*r*, write the volume V as a function of the diameter d.

- V = \frac{32}{3} \pi d^3
*V*=332*πd*3 - V = \frac{1}{6} \pi d^3
*V*=61*πd*3 **V = \frac{8}{3} \pi d^3***V*=38*πd*3- V = \frac{16}{3} \pi d^3
*V*=316*πd*3

Q5. A water droplet has volume 0.1 cubic cm. Convert the volume of the droplet to cubic meters (1m = 100cm). volume = _______ cubic m.

Preview will appear here…

**Answer: The volume of the water droplet is 0.0000001 cubic meters.**

Q6. Compound X is made up of two parts A and one part B. The mass of compound X is 45, and A has twice the mass of B. Which two equations would you solve to find the individual masses of A and B?

**2A+B = 45**- A = 2B
- A+B = 45
- A = 2B
- A+B = 45
- 2A = B
- 2A+B=45
- 2A = B

Q7. An architect presents a 3 inch wide by 4 inch deep by 3 inch tall model of a new central campus dorm. If the final building foundation is 126 feet wide, how deep (in feet) will the building be?

Q8.Methane (CH_4*C**H*4) burns in the presence of Oxygen (O_2*O*2) to make Carbon Dioxide (CO_2*C**O*2) and Water (H_2O*H*2*O*) according to the following chemical equation:

CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O*C**H*4+2*O*2→*C**O*2+2*H*2*O*

How many molecules of Oxygen are consumed if 24 molecules of Carbon Dioxide are produced?

Q9. If x = 0.2y, then what is x^3*x*3?

- x^3 = 0.04y^3
*x*3=0.04*y*3 **x^3 = 0.6y^3***x*3=0.6*y*3- x^3 = 0.02y^3
*x*3=0.02*y*3 - x^3 = 0.008y^3
*x*3=0.008*y*3

Q10. A volume (V) of 20L of gas is kept in a container with flexible walls at constant temperature (T) and the pressure (P) is observed to increase from 2 bar to 4 bar. If n and R are constant and PV=nRT, then what must have happened to the volume?

- it stayed the same
- it doubled
**it halved**- not enough information

Q11. Given the equation PV = nRT, the variables P, V, n, and T have units given in the table below.

Variable | Symbol | Units | Abbreviation |

Temperature | T | Kelvin | K |

Pressure | P | bar | bar |

Volume | V | Liters | L |

Number of moles | n | moles | mol |

What are the units of constant R?

**(L \cdot bar)/(mol \cdot K)***L*⋅*bar*)/(*mol*⋅*K*)- (bar \cdot K) / (L \cdot mol)(
*bar*⋅*K*)/(*L*⋅*mol*) - (mol \cdot K)/(L \cdot bar)(
*mol*⋅*K*)/(*L*⋅*bar*) - (L \cdot mol)/(bar \cdot K)(
*L*⋅*mol*)/(*bar*⋅*K*)

Q12. Use the graphs of f and g to evaluate g(f(2)).

**1**- -2
- 0
- 2
- None of the above

Q13. Which of the following formulas defines the area, A , of a square in terms of its perimeter, p?

- A = 16x^2
*A*=16*x*2 **A = s^2***A*=*s*2- A = \frac{p^2}{16}
*A*=16*p*2 - A = \frac {p^2}{4}
*A*=4*p*2 - p = 4 \sqrt{A}
*p*=4*A*

Q14. A ball is thrown into a lake, creating a circular ripple that travels outward at 5 cm per second. Express the area, A = , of the circle in terms of the time, t , (in seconds) that has passed since the ball hits the lake.

**A = 25 \pi t^2***A*=25*πt*2- A = \pi t^2
*A*=*πt*2 - A = 25 \pi t
*A*=25*πt* - A = 10 \pi t
*A*=10*πt* - A = 5 \pi t^2
*A*=5*πt*2

Q15. Assume that water is poured into a spherical bottle at a constant rate. Which of the following graphs best represents the height of water in the bottle as a function of the amount of water in the bottle?

#### Week 1 Exercises

Q1. Classify the following statement as a prediction, observation, theory, or law. Please be sure to classify the statement exactly as it is written!

Oppositely charged objects are attracted to each other.

- Observation
- Law
**Theory**- Prediction

Q2. Classify the following statement as a prediction, observation, theory, or law. Please be sure to classify the statement exactly as it is written!

If he kicks the ball, then it will go into the goal.

**Prediction**- Law
- Observation
- Theory

Q3. Classify the following statement as a prediction, observation, theory, or law. Please be sure to classify the statement exactly as it is written!

The New York Mets will win the 2014 Major League Baseball National League Pennant. (assuming it is prior to 2014)

- Law
- Theory
**Observation**- Prediction

Q4. Express the following number in **scientific notation**. Do **NOT** include unit in your answer. Please use **e** to refer to power of 10. For example, 1 x 10^6 should be entered as **1e6**, 4.5 x 10^-7 should be entered as **4.5e-7.**

Radius of the atomic nucleus of an aluminum atom is 0.0000000000000036 m, scientific notation is ______ m.

Q5. Express the following number in **scientific notation**. Do **NOT** include unit in your answer. Please use **e** to refer to power of 10. For example, 1 x 10^6 should be entered as **1e6**, 4.5 x 10^-7 should be entered as **4.5e-7.**

Typical length of time it takes to blink an eye is 0.250 s, scientific notation is ______ s.

Q6. Express the following number in **scientific notation**. Do **NOT** include unit in your answer. Please use **e** to refer to power of 10. For example, 1 x 10^6 should be entered as **1e6**, 4.5 x 10^-7 should be entered as **4.5e-7.**

The mass of a typical grown female elephant is 2,100 kg, scientific notation is _______ kg.

Q7. How many significant figures are there in the following numbers? (Enter one Arabic number to indicate the number of significant figures)

305,000

Q8. How many significant figures are there in the following numbers? (Enter one Arabic number to indicate the number of significant figures)

0.0210

Q9. Perform the following calculation and input the answer expressed to the correct number of significant figures.

The goal of this question is to see if you understand how the mathematical operations affect the significant figures. If you are not sure about this, then please review the videos for this week.

80720 \div \left( 555 \times 196 \right) =80720÷(555×196)=______

Q10. Perform the following calculation and input the answer expressed to the correct number of significant figures.

The goal of this question is to see if you understand how the mathematical operations affect the significant figures. If you are not sure about this, then please review the videos for this week.

\left(15.3 – 7.009\right) \times 1.86 =(15.3−7.009)×1.86=_____

Q11. A Boeing 747 carries 1.834 \times 10^51.834×105 liters of jet fuel. Convert this volume to cm^3*c**m*3. (hint: please feel welcome to use a table of useful conversion factors). Please use **e** to refer to power of 10. For example, 1 x 10^6 should be entered as **1e6**, 4.5 x 10^-7 should be entered as **4.5e-7.**

The answer is ______ cm^3*cm*3.

Preview will appear here…

Q12. Which of the following elements exists in nature as a diatomic molecule?

- Fe
- K
**Si**- Rn
- Cl

Q12. Select ALL that apply in describing the following species.

H_2*H*2

**Element****Molecule**- Atom
- Compound

Q14. Consider the following representation of charge interactions, all of which are in the same dielectric medium:

If the particles in situation c are slowly pushed closer together, indicate whether the potential energy of the system increases, decreases, or is unchanged?

- decreases
**unchanged**- increases

Q15.How many moles of oxygen atoms are present in 0.350 moles of Na_2CO_3*N**a*2*C**O*3, a commonly used water softener?

The answer is ________ moles of oxygen atoms.

### Introduction to Chemistry: Reactions and Ratios Week 02 Quiz Answers

#### Week 2 Exercises

Q1. Which of the following statements about **neutrons** are true? Check all that apply.

Neutrons _______.

- have a charge of -1
- have about the same mass as electrons
**can vary in number to make different isotopes of the same element****are located in the nucleus of the atom**- have a charge of +1

Q2. How many **protons** are in the nucleus of an **iron** atom?

Q3. Select the best description for the following element:

krypton

**1 point**

**Nonmetal**- Metalloid
- Metal

Q4. Select ALL of the elements that **readily form cations** by checking the correct boxes below. (Check all that apply)

**lithium****barium**- sulfur
- helium
**aluminum****cesium**- fluorine
- bromine

Q5. Identify each of the following ions with their correct chemical symbol.

Input Instructions:

Please **do NOT** use any special characters for superscripts, and be careful with capitalization! For example, Cl^{1-}*C**l*1−, the chloride ion, should be entered as Cl1-.

Species with 8 protons and 10 electrons.

Q6. Identify each of the following ions with their correct chemical symbol.

Input Instructions:

Please **do NOT** use any special characters for superscripts, and be careful with capitalization! For example, Cl^{1-}*C**l*1−, the chloride ion, should be entered as Cl1-.

Species with 7 protons and 10 electrons.

Q7. Determine the number of **protons** or **neutrons** in the following isotope:

Cr-53

number of protons is _____ ; number of neutrons is 29.

Q8. Which of the following atoms is the **most** electronegative

**1 point**

- P
- Si
**Sr**- Ni
- O

Q9. Which of the following neutral atoms has the **largest** first ionization energy?

- K
- Cl
**Ne**- Zn
- P

Q10. Calculate ΔE for a system that releases 41 J of heat while 28 J of work is done by the system.

- -13 J
- 13 J
- 41 J
**-69 J**- 69 J

Q11. Calculate the amount of heat transferred when 550 grams of water warms from an initial temperature of 4.0 ºC to a final temperature of 25.0 ºC. The specific heat capacity of liquid water is 4.184 J/g ºC. *Please express you answer as a number in units of kJ, and be careful about the sign (is the answer a positive or negative number?) since that shows the direction of heat flow.*

Q12. Use the following table for necessary information:

A support rod is said to be solid titanium. You conduct some experiments at room temperature and discover that it displaces 87.82 mL of water and has a mass of 395.2 g. Can this really be made of pure titanium?

**Yes**- No

### Introduction to Chemistry: Reactions and Ratios Week 03 Quiz Answers

#### Week 3 Exercises

Q1. Naming the following compound. Please note that spelling and formatting (upper versus lower case and spacing) are important in terms of having your answer marked as correct! Please use US spellings of the elements with all lower case letters (except for Roman numerals which are upper cases) and be very careful about spacing (only add spaces when they are necessary for the name!) For example, Al_2O_3*Al*2*O*3 should be written using lower cases as **aluminum oxide**. FeBr_2*FeBr*2 should be written as **iron(II) bromide**.

ZnBr_{2}

Q2. Naming the following compound. Please note that spelling and formatting (upper versus lower case and spacing) are important in terms of having your answer marked as correct! Please use US spellings of the elements with all lower case letters (except for Roman numerals which are upper cases) and be very careful about spacing (only add spaces when they are necessary for the name!) For example, Al_2O_3*Al*2*O*3 should be written using lower cases as **aluminum oxide**. FeBr_2*FeBr*2 should be written as **iron(II) bromide**.

SO_{3}

Q3. Naming the following compound. Please note that spelling and formatting (upper versus lower case and spacing) are important in terms of having your answer marked as correct! Please use US spellings of the elements with all lower case letters (except for Roman numerals which are upper cases) and be very careful about spacing (only add spaces when they are necessary for the name!) For example, Al_2O_3*Al*2*O*3 should be written using lower cases as **aluminum oxide**. FeBr_2*FeBr*2 should be written as **iron(II) bromide**.

CuSO_{4}

Q4. Naming the following compound. Please note that spelling and formatting (upper versus lower case and spacing) are important in terms of having your answer marked as correct! Please use US spellings of the elements with all lower case letters (except for Roman numerals which are upper cases) and be very careful about spacing (only add spaces when they are necessary for the name!) For example, Al_2O_3*Al*2*O*3 should be written using lower cases as **aluminum oxide**. FeBr_2*FeBr*2 should be written as **iron(II) bromide**.

Cu_{2}Se

Q5. Use the values on the periodic table to calculate the formula mass of each of the following compound. Do NOT worry about the significant figures.

MnO_{2}

Q6. How many molecules of ammonia are present in 34 g of ammonia (Formula = NH_{3})?

- 1.8 × 10
^{1} **3.6 × 10**^{23}- 2.9 × 10
^{-25} - 1.1 × 10
^{23} - 1.2 × 10
^{24}

Q7. Fill in the blank with the best answer choice: Atoms having greatly different electronegativities are expected to form ___________________.

- hydrogen bonds
- polar covalent bonds
- ionic bonds
**nonpolar covalent bonds**

Q8. Which of the following formulas is * not* correct based upon what you know about preferred oxidation states and charges on monatomic or polyatomic ions?

- CaS
**Mg**_{2}SO_{4}- NaI
- LiNO
_{3} - K
_{2}O

Q9. What is the oxidation state of nitrogen in an N_{2} molecule?

- -3
- -1
- 0
**+1**- +3

Q10. Use the values on the periodic table to calculate the formula mass of each of the following compound. Do NOT worry about the significant figures.

Al(OH)_3*Al*(*OH*)3

Q11. Which compound has the largest molar mass?

- C_2H_4O
*C*2*H*4*O* **CH_3Cl***CH*3*Cl*- CO_2
*CO*2 - C_2H_6
*C*2*H*6

### Introduction to Chemistry: Reactions and Ratios Week 04 Quiz Answers

#### Week 4 Exercises

Q1. How many **grams** of **nitrogen** are in a sample of Al(NO_{3})_{3} that contains 364.0 g of aluminum?

Answer: ________ grams of nitrogen.

Q2. A helium balloon contains 0.42 g of helium. How many moles of helium are in the balloon?

Answer: ______ moles.

Q3. Silver has only two naturally occurring, stable isotopes: Ag-107 and Ag-109. The mass of Ag-107 is 106.9051 u, and the mass of Ag-109 is 108.90475 u.

Determine the average relative abundance Ag-109 in a naturally occurring sample. (Hint: you need to look up the average relative atomic mass of silver on the periodic table to solve this problem.)

Fill in the blank: ______________ % Ag-109

**48.16**- 44.36
- 51.84
- 69.72
- 60.11

Q5. Consider the following *unbalanced* chemical equation:

Fe_{2}O_{3(s)} + CO_{(g)} → Fe_{(s)} + CO_{2(g)}

Balance the reaction using the smallest whole number coefficients. What is the coefficient in front of the solid iron product in the balanced chemical equation?

- 1
- 2
- 3
- 4
**none of the above**

Q6. Xenon tetroxide is a rare example of a compound that contains a noble gas. What is the mass percent of oxygen in xenon tetroxide?

Q7. Fill in the blank with a number between 1 and 100 and at least **4** significant figures: the answer is _________%

Calculate the molar mass of propane (C_{3}H_{8}). The answer is: ________ g/mol.

- 34.17
**44.10**- 38.90
- none of the above are within +1% of the correct value.
- 46.07

Q7. Balance the following chemical reaction equation using the smallest whole number coefficients.

The sum of the coefficients is: ________ (Please enter a whole number, and don’t forget to add in any coefficients of 1!)

___ Al + ___ S_{8} → ___ Al_{2}S_{3}

Q8. A compound has an empirical formula of C_{7}H_{12}O and a formula mass of 224 g/mol. What is the compound’s molecular formula?

**C**_{14}H_{24}O_{2}- C
_{21}H_{36}O_{3} - C
_{7}H_{12}O - C
_{12}H_{16}O_{4} - C
_{9}H_{12}O_{3}

Q9. Calculate how many grams of the product form when 16.7 g of calcium metal completely reacts. Assume that there is more than enough of the chlorine gas.

Ca_{(s)} + Cl_{2(g)} → CaCl_{2(s)}

Answer is ______ g.

### Introduction to Chemistry: Reactions and Ratios Week 05 Quiz Answers

#### Week 5 Exercises

Q1. Write down the dissolution equation for rubidium chromate dissolving in water. (Chromate is a polyatomic ion with the formula CrO_{4}^{2-}.) If two moles of the ionic compound are dissolved, then how many moles of the CATION are present in the solution?

Q2. A 15.7 g sample of KBr is dissolved in water to give 6.50 \times 10^26.50×102 mL of solution. The concentration of the solution is:

**0.203 M***M*- 0.0203 M
*M* - 0.0640 M
*M* - 0.640 M
*M*

Q3. Given the following solubility product constant (K_{sp}*K**s**p*) values

BaSO_{4} 1.5 \times 10^{–9}1.5×10–9

CoS 5.0 \times 10^{–22}5.0×10–22

PbSO_{4} 1.3 \times 10^{–8}1.3×10–8

AgBr 5.0 \times 10^{–13}5.0×10–13

BaCO_{3} 1.6 \times 10^{–9}1.6×10–9

Which of the following compounds is the most soluble (in moles per liter)?

**PbSO**_{4}- BaCO
_{3} - AgBr
- CoS
- BaSO
_{4}

Q4. Check ALL of the following substances which will conduct electricity in the form given:

- sand
- 0.1 M0.1
*M*glucose (sugar) water - FeSO
_{4(s)} **1 M1***M*HNO_{3}in water**0.1 M0.1***M*solution of lithium sulfate

Q5. A solution is known to contain *only one* type of cation. Addition of Cl^{1-} ion to the solution had no apparent effect (all ions remained in solution), but addition of SO_{4}^{2-} ion resulted in a precipitate. Which cation is present?

- Zn
^{2+} - K
^{1+} - NH
_{4}^{1+} **Sr**^{2+}- none of the canions listed in the other choices are present

Q6. Write the balanced chemical equation for the dissolution of **ammonium nitrate**. What is the coefficient in front of the solvated anion?

- 0
- 1
- 2
- 3
**4**

Q7. Write the formula for the dissolution of **barium acetate** in water.

How many TOTAL ions (**barium cations + acetate anions**) would be produced as aqueous species in the water solvent if four molecules of **barium acetate** dissolved? The answer is _____ total ions (Please enter your answer as a whole number.)

Q8.Select ALL of the following compounds which can be dissolved in water to prepare a 0.2 M aqueous solution. (Hint: use solubility rules)

- calcium sulfate
**cadmium chloride****ammonium sulfate****zinc iodide**- mercury(I) bromide
- bismuth hydroxide

Q9. Potassium phosphate reacts with magnesium chlorate, Mg(ClO_{3})_{2(aq)}, in aqueous solution to form a precipitate. What is the net ionic equation for this reaction?

- K
^{+}_{(aq)}+ PO_{4}^{3–}_{(aq)}+ Mg^{2+}_{(aq)}+ ClO_{3}^{–}_{(aq)}→ KClO_{3(s)}+ MgPO_{4(s)} - K
^{+}_{(aq)}+ ClO^{3–}_{(aq)}→ KClO_{3(s)} **3Mg**^{2+}_{(aq)}+ 2PO_{4}^{3–}_{(aq)}→ Mg_{3}(PO_{4})_{2(s)}- Mg
^{2+}_{(aq)}+ PO_{4}^{3–}_{(aq)}→ Mg_{3}(PO_{4})_{2(s)} - K
^{+}_{(aq)}+ ClO_{3}^{2-}_{(aq)}→ K_{2}ClO_{3(s)}

Q10. Each of the following pairs of 0.2 M aqueous solutions are mixed. Which mixture results in the formation of a precipitate?

- ammonium chloride + potassium carbonate
- beryllium nitrate + aluminum sulfate
**sodium sulfate + potassium acetate**- lead(II) acetate + rubidium iodide

### Introduction to Chemistry: Reactions and Ratios Week 06 Quiz Answers

#### Week 6 Exercises

Q1. Identify ALL of the molecules that could react as a Brønsted-Lowry acid in a chemical reaction:

**H**_{3}PO_{4}- CO
_{2} **H**_{2}O- FeCl
_{3} **HCl**

Q2. Which one of the following mechanistically depicts the acid-base reaction that occurs when hydrobromic acid(HBr) is added to methanol (CH_{4}O)?

*Reminder: curved arrow notation is used to show the movement of electrons.*

**A**- B
- C
- D

Q3. Which of the following are **strong acids**? Please select ALL that are strong acids.

- CH
_{4} **H**_{2}SO_{4}- NaOH
**HCl**- HF
**HNO**_{3}

Q4. Which of the following reactions are redox reactions? (please select all that apply)

**2 KMnO**_{4(s)}+ 3 Na_{2}SO_{3(s)}+ H_{2}O_{(I)}→ 2 MnO_{2(s)}+ 3 Na_{2}SO_{4(s)}+ 2 KOH_{(s)}**Al_{(s)}(***s*) + 3 Ag^{1+}_{(aq)}(*aq*) → Al^{3+}_{(aq)}(*aq*) + 3 Ag_{(s)}(*s*)**4 K_{(s)}(***s*) + O_{2}_{(g)}(*g*) → 2 K_{2}O_{(s)}(*s*)- SO
_{3}_{(g)}(*g*) + H_{2}O_{(l)}(*l*) → H_{2}SO_{4}_{(aq)}(*aq*)

Q5. Identity what type of chemical reaction this is:

H_{2(g)} + I_{2(s)} ⇌ 2HI_{(g)}

- dissolution
**oxidation-reduction**- precipitation
- acid-base neutralization

Q6. In the reaction Zn + H_{2}SO_{4} → ZnSO_{4} + H_{2}, which element, if any, is reduced?

- sulfur
**none of the elements are reduced in this reaction**- oxygen
- hydrogen
- zinc

Q7. Consider the complete reaction of **43.0 g of silicon with excess nitrogen gas in the reaction shown below. What mass of product forms?3Si + 2N _{2} → Si_{3}N_{4} Answer = _________ grams of product**

Q8. In a particular reaction, 53.8 g of liquid silicon tetrachloride is added to 65.0 g of solid magnesium to produce solid magnesium chloride and solid silicon. What is the ** excess reagent** for the forward reaction?

- Si
- MgCl
_{2} **SiCl**_{4}- Mg

Q9. Determine the oxidation state of the nitrogen in each of the following molecules or ions.

N_{2} and NO_{2}^{1-}

- +1 and +1
- +2 and +3
**0 and -2**- 0 and +3

### Introduction to Chemistry: Reactions and Ratios Week 07 Quiz Answers

#### Final Exam Part A

Q1. Perform the following calculation to one significant figure:

2.4 – 1.776 = ______

- 0.624
- 0.6240
- 0.62
**4.2**- 0.6

Q2. What is the chemical symbol of the alkaline earth metal in the same period as chlorine?

- Fe
**Na**- Mg
- Li
- Al

Q3. What is the chemical formula of magnesium cyanide?

- MgCN
- Mg
_{2}CN **Mg(CN**^{1-})_{2}- Mg(CN)
_{2} - MgCN
_{2}

Q4. What is the mass of 0.6134 moles of gold atoms?

- 0.6134 g
- 120.8 g
**96.46 g**- 0.003114 g
- 0.007765 g

Q5. The substance with the formula S_{8} is a/an:

**molecule and an element**- compound only
- molecule and a compound
- element only
- atom and an element

Q6. What is the formula mass of Al_{2}(SO_{4})_{3}?

**342.15 u**- 399.88 u
- 75.04 u
- 150.02 u
- 214.16 u
- none of the other answers are within 2% of the correct answer

Q7. Consider the force of interaction between a cation and an anion. Which of the following does *not* make the force more attractive? (Recall Coulomb’s law has the formula F = kq_{1}q_{2}/(εr^{2})

**Change the charge on the anion so that it is less negative**- Decrease the distance between the ions
- Increase the charge on the cation so that it is more positive
- Decrease the dielectric constant of the fluid between the ions
- All of the other answer choices listed make the force more attractive

Q8. Which of the following substances will conduct electricity well in the form and state listed?

**1.0 M aqueous solution of sodium bromide**- Deionized water
- Solid sodium chloride
- Two or more of the other answers are substances that conduct electricity well
- None of the other answers are substances that will conduct electricity well

Q9. A chemist prepares a solution by dissolving 0.3 mole of CaCl_{2} in enough water to make 1000 mL of solution. What is the molar concentration of chloride ions?

- 0.2 M
- 0.4 M
- 0.3 M
**0.6 M**- 0.1 M

Q10. A single tablet of regular strength Tylenol contains 325 mg of the active ingredient, acetaminophen (C_{8}H_{9}NO_{2}, molar mass = 151.17 g/mol.) What is the mass percent of oxygen in acetaminophen?

- 68.8%
- 42.3%
**0.0455%**- 5.29%
- 21.2%
- 10.6%

Q11. Consider the following *unbalanced* chemical equation for the reaction which is used to determine blood alcohol levels:

H^{1+} + Cr_{2}O_{7}^{2-} + C_{2}H_{6}O → Cr^{3+} + CO_{2} + H_{2}O

In the forward reaction, is chromium oxidized and/or reduced?

**reduced**- oxidized
- both oxidized and reduced
- neither oxidized nor reduced
- this is not a redox reaction

Q12. An experimental technique called elemental analysis reveals that particular antibiotic is composed of 53.827% carbon, 6.453% hydrogen, 8.968% nitrogen, 10.27% sulfur, and *the rest is oxygen.* What is the empirical formula of penicillin F?

- C
_{54}H_{6}N_{9}S_{10}O_{20} - C
_{5}H_{6}NSO - C
_{14}H_{20}N_{2}SO_{4} **C**_{14}H_{20}N_{2}SO_{3}- C
_{54}H_{6}N_{9}S_{10}

#### Final Exam Part B

Q1. Which element has the chemical symbol Ar?

- Gold
**Argon**- Arsenic
- Actinium
- Silver

Q2. Which of the following species has 29 protons and 28 electrons?

**Cu^{1**+**}1+**- Ni^{1-}1−
- Si^{1+}1+
- Si
**Ni^{1+}1+**

Q3. What is the chemical formula of copper(I) sulfide?

- CuSO_33
- CuS_22
- CuSO_44
**Cu_22S**- CuS

Q4. What is the name of the following compound: SiBr_44

- Silicon(IV) bromide
- silicon(I) bromide
**silicon tetrabromide**- silicon(IV) tetrabromide
- silicone bromate

Q5. The chemical formula of potassium thiosulfate is K_22S_22O_33. What is the oxidation state of sulfur in this compound?

- +2
**-2**- 0
- -1
- +1

Q6. Consider the following ion: 54-Mn^{2+}2+. How many neutrons and electrons are present in this ion?

- 23 neutrons and 30 electrons
- 54 neutrons and 52 electrons
- 30 neutrons and 28 electrons
- 29 neutrons and 23 electrons
**29 neutrons and 25 electrons**

Q7. Please select the atom with the smallest ionization energy of those listed below:

- lithium
- potassium
- rubidium
**cesium**- sodium

Q8. Which of the following elements is a metal?

- Carbon
**Vanadium**- Selenium
- Krypton
- Silicon

Q9. What is the minimum mass of sodium hydroxide required to neutralize a solution that was prepared by dissolving 9.16 g of hydrochloric acid (HCl) in excess water?

**9.16 g**- 10.0 g
- 14.7 g
- 5.07 g
- 6.28 g

Q10. What is the solubility product constant (K_{sp}*sp*) expression for the dissolution of CaCl_22?

**K_{sp}***sp*=[Ca^{2+}2+][Cl^{1-}1−]^22- K_{sp}
*sp*=[Ca^{2+}2+]^++[Cl^{1-}1−]^22 - K_{sp}
*sp*=[Ca^{2+}2+]^22[Cl^{1-}1−] - K_{sp}
*sp*=[Ca^{2+}2+]^22[2Cl^{1-}1−] - None of the other answers are correct

Q11. A solution is known to contain **only one** type of cation. The addition of SO_44^{2-}2− ion to the solution had no apparent effect, but the addition of Br^{1-}1− ion resulted in the formation of a precipitate. Which cation is present?

**Cu^{1+}1+**- Li^{1+}1+
- Ca^{2+}2+
- Pb^{2+}2+
- None of the cations listed in other answer choices could be in the solution

Q12. Consider the following **unbalanced** chemical equation for the reaction which is used to determine blood alcohol levels:

H^{1+}1+ + Cr_22O_77^{2-}2− + C_22H_66O \rightarrow→ Cr^{3+}3+ + CO_22 + H_22O

Balance the equation using the smallest whole number coefficients. What is the coefficient in front of carbon dioxide in the balanced chemical equation?

**2**- 1
- 3
- 4
- none of the other answers is correct

Q13. Two solid objects of the same volume are compared in an experiment. One of the objects floats when placed in a water bath, and the other one sinks when placed in the same water bath at the same temperature. Which property of these two objects must be different to account for this observation?

- Molarity
- Ionization Energy
- Electronegativity
- Polarity
**Density**

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