Final – Flashcard Answers

What follows an element’s symbol in a chemical formula to indicate the number of atoms of that element in one molecule of the compound?

a. charge sign
b. superscripted number
c. number in parentheses
d. subscripted number

The chemical formula for an ionic compound represents one

a. formula unit
b. ion
c. molecule
d. cation

What is the correct notation for a calcium ion whose outer shell is a full octet?

a. Ca¹⁺
b. Ca²⁺
c. Ca¹⁻
d. Ca²⁻

What is the correct name for the NO₃⁻ ion?

a. nitrate
b. nitrite
c. nitride
d. nitrogen oxide

What is the correct formula for copper(I) cyanide?

a. CuCy
b. CuCy₂
c. CuCN
d. Cu₂CN

What is the correct name for the acid CH₃COOH?

a. carbonic acid
b. carbonate acid
c. acetic acid
d. acetous acid

What is the correct name for the compound P₂Cl₄?

a. phosphorus chloride
b. phosphorus tetrachloride
c. diphosphorus chloride
d. diphosphorous tetrachloride

What is the correct formula for the compound made of magnesium and nitrogen?

a. Mg₂N₃
b. Mg₃N₂
c. MgN₂
d. MgN

Oxidation numbers are used to indicate the

a. charge on an ion
b. number of atoms or ions in a compound
c. type of bond holding particles together in a compound
d. distribution of electrons among the bonded particles in a compound

Atoms have an oxidation number of zero in a(n)

a. pure element
b. acid
c. ionic compound
d. molecular compound

What is the oxidation number of nickel in NiCO₃?

a. 0
b. +1
c. +2
d. +3

What is the correct name for the compound Ni₂O₃ using the Stock system?

a. nickel(II) oxide
b. dinickel trioxide
c. nickel trioxide
d. nickel(III) oxide

What is the oxidation number of phosphorus in the PO₄³⁻ ion?

a. -3
b. 0
c. +5
d. +8

What is the correct formula for the compound platinum(VI) fluoride?

a. PtF₃
b. PtF₆
c. Pt₆F₂
d. Pt₆F

The formula mass of any compound is described in units of

a. grams
b. AMU
c. moles
d. grams per mole

The molar mass of water is equal to

a. 1g of O plus 2g of H
b. 1g of O plus 1g of H
c. the mass of 1 mol of O plus the mass of 1 mol of H
d. the mass of 1 mol of O plus the mass of 2 mol of H

What is the molar mass of pure tin?

a. 1.00 g/mol
b. 47.88 g/mol
c. 118.71 g/mol
d. 237.42 g/mol

How many moles of compound are there in 15.0g of potassium dichromate, K₂Cr₂O₇?
(The molar mass of K₂Cr₂O₇ is 294.2g)

a. 0.0510 mol
b. 11.0 mol
c. 15.0 mol
d. 294 mol

What is the mass percentage of cobalt in cobalt(II) fluoride, CoF₂?

a. 33.33%
b. 39.20%
c. 60.80%
d. 96.93%

What is the mass of 4.80 mol of barium hydride, BaH₂?

a. 4.80g
b. 29.0g
c. 139g
d. 660g

Which of the following molecular formulas does not have the corresponding empirical formula XY₂Z₂?

a. X₂Y₄Z₂
b. XYZ
c. X₆Y₁₂Z₆
d. X₃Y₆Z₃

The simplest whole-number ratio of moles of each element in a compound is known as the

a. percent composition
b. empirical formula
c. Stock formula
d. molecular formula

What is the empirical formula for a compound that contains 12.61% Li, 29.17% S, and 58.21% O?

a. LiSO₂
b. LiS₂O₆
c. Li₂SO₄
d. Li₂SO₃

What is the molecular formula for the compound with a formula mass of 58.12 AMU and an empirical formula of C₂H₅?

a. C₂H₅
b. C₄H₁₀
c. C₆H₁₅
d. C₈H₂₀

What is the molecular formula for the compound that is made up of 30.45g N and 69.55g O, and has a formula mass of 92.02 AMU?

a. NO
b. N₂O₂
c. NO₂
d. N₂O₄

You mix solution A with solution B in a beaker. Which of the following observations does not help you prove that a chemical reaction has occurred?

a. The beaker becomes warm
b. You see gas bubble out of solution
c. Solution A, solution B, and the mixture are all yellow
d. None of the above; all help prove that a chemical reaction has occurred

In the reaction described by the word equation “sodium + water → sodium hydroxide + hydrogen gas”

a. sodium hydroxide is a product
b. sodium is a product
c. water is a reactant
d. Both (a) and (c)

Which of the following indicates that a chemical equation is balanced?

a. The numbers of atoms of each element are the same on both sides of the equation
b. All of the coefficients are the same
c. The numbers of molecules on each side of the equation are equal
d. The sums of the coefficients on each side of the equation are equal

From a complete and correctly written chemical equation, you can obtain the

a. chemical formulas of the reactants and products
b. relative amounts of the reactants and products
c. physical states of the reactants and products
d. All of the above

To balance a chemical equation, you must

a. adjust the subscripts
b. adjust the number of products
c. c. adjust the number of reactants
d. adjust the coefficients

The formation of a solid product in a chemical reaction is represented by the symbol

a. (aq)
b. (g)
c. (l)
d. (s)

What symbol indicates a reversible reaction?

a. ↔
b. ↑
c. →
d. ←

In the expression 3CO₂, the numbers 3 and 2 are, respectively,

a. a subscript and a coefficient
b. a coefficient and a subscript
c. two subscripts
d. two coefficients

What is the total number of molecules that is represented by the following chemical equation?
NH₄NO₂→ N₂+2H₂O

a. 3
b. 4
c. 8
d. 16

Which equation below violates the law of conservation of mass?

a. 2H₂+O₂→ 2H₂O
b. KCl+Br₂→KBr+Cl₂
c. 2Fe₂O₃+3C→4Fe+3CO₂
d. Na₂CO₃+2HCl→2NaCl+H₂O+CO₂

Which of the following equations represents the balanced equation for the reaction of iron and oxygen?

a. 2Fe+O₂→Fe₂O₃
b. Fe+3O₂→Fe₂O₃
c. 4Fe+3O₂→2Fe₂O₃
d. 3Fe

Which coefficients correctly balance the formula equation below?
KClO₃(s)→KCl(s)+O₂(g)

a. 1, 1, 1
b. 1, 1, 2
c. 2, 2, 3
d. 2, 1, 1

Which equation is not balanced?

a. 2H₂+O₂→ 2H₂O
b. 4H₂+2O₂→4H₂O
c. H₂+H₂+O₂→H₂O+H₂O
d. 2H₂+O₂→H₂O

In which type of reaction do two or more compounds react to form one product?

a. synthesis
b. decomposition
c. combustion
d. single-displacement

Which of the following is true regarding single-displacement reactions?

a. Only one product is formed
b. There is only one reagent
c. It requires oxygen
d. One element replaces another in a compound.

Which of the following is true regarding double-displacement reactions?

a. Two products are formed
b. The ions of the two reactants must be exchanged.
c. A precipitate may form
d. All of the above

A mixture of propane and oxygen react to form carbon dioxide and water.
What type of chemical reaction is this?

a. synthesis
b. decomposition
c. double-displacement
d. combustion

What type of chemical reaction does the following chemical equation represent?
2HCl(aq)+Cr(s)→H₂(g)+CrCl₂(aq)

a. composition
b. single-displacement
c. decomposition
d. double-displacement

Calcium carbonate, CaCO₃, reacts to form calcium oxide, CaO, and carbon dioxide, CO₂.
What type of reaction is this?

a. synthesis
b. replacement
c. combustion
d. decomposition

What type of chemical reaction is represented by the following word equation?
Iron + Oxygen → Iron(II) oxide

a. synthesis
b. replacement
c. combustion
d. double-replacement

Metal X replaces the ions of metal Y from solution, but it cannot replace the ions of metal Z from solution. The order of these metals should have in the activity series (from top to bottom) is

a. X, Y, Z
b. Z, X, Y
c. Y, X, Z
d. Z, Y, X

In a single-displacement reaction, an element in the activity series most likely can replace any element

a. above it on the list
b. in the same group
c. below it on the list
d. in any other group

The activity series helps to predict

a. the amount of product formed by a chemical reaction
b. whether or not a specific chemical reaction is possible
c. the coefficients needed to balance a chemical equation
d. the amount of energy needed to start a chemical reaction

If calcium is listed above magnesium in the activity series, and magnesium is listed above zinc, which of the following reactions is possible?

a. Ca+MgCl₂
b. Zn+MgCl₂
c. Zn+CaCl₂
d. Mg+CaCl₂

You have an unknown metal, X. You conduct two experiments. The results are shown in the table below.
Which of the following statements is a logical conclusion based on the experimental data?

a. The unknown metal is higher on the activity series than both sodium and zinc
b. The unknown metal is higher on the activity series than sodium, but below zinc
c. The unknown metal is higher on the activity series than zinc, but below sodium
d. The unknown metal is below both sodium and zinc on the activity series

A balanced chemical equation allows one to determine the

a. mole ratio of any two substances in the reaction
b. energy released in the reaction
c. electron configuration of all elements in the reaction
d. mechanism involved in the reaction

The coefficients in a chemical equation represent the

a. masses, in grams, of all reactants and products
b. relative numbers of moles of reactants and products
c. number of atoms in each compound in a reaction
d. number of valence electrons involved in the reaction

Actual yield must be determined by

a. experiments
b. calculations
c. theoretical yield
d. estimation

The actual yield of a chemical reaction is generally

a. less than the theoretical yield
b. greater than the theoretical yield
c. equal to the percentage yield
d. greater than the percentage yield

To determine the limiting reactant in a chemical reaction involving known masses of the two reactants, which of the following would be most useful?

a. determining the masses
b. determining the molar masses of the products
c. calculating bond energies
d. calculating the mass of a single product formed from each reactant

How many mole ratios can be correctly obtained from the chemical equation 2Al₂O₃→4Al+3O₂?

a. 3
b. 4
c. 6
d. 8

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In the equation 2Al₂O₃→4Al+3O₂, what is the mole ratio of aluminum to oxygen?

a. 10:6
b. 3:4
c. 2:3
d. 4:3

Fewer steps are required to solve stoichiometry problems when

a. the reactant is given in grams and the product is sought in grams
b. the reactant is given in moles and the product is sought in moles
c. the reactant is given in grams and the product is sought in liters
d. the reactant is given in liters and the product is sought in number of atoms

Which of the following mathematical expressions correctly states the relationship among percentage yield, actual yield, and theoretical yield?

a. actual yield= percentage yield/theoretical yield • 100
b. percentage yield= actual yield/theoretical yield • 100
c. theoretical yield= actual yield/percentage yield • 100
d. Both B and C