Chemistry worksheet
    Topic: Moles And Stoichiometry
    Moles And Stoichiometry
    1

    What is the chemical formula for sodium oxalate?

    (1) NaO

    (2) Na2O

    (3) NaC2O4

    (4) Na2C2O4

    2

    What is the chemical name of the compound NH4SCN?

    (1) ammonium thiocyanate

    (2) ammonium cyanide

    (3) nitrogen hydrogen cyanide

    (4) nitrogen hydrogen sulfate

    3

    Which statement explains why NaBr is classifi ed as a compound?

    (1) Na and Br are chemically combined in a fixed proportion.

    (2) Na and Br are both nonmetals.

    (3) NaBr is a solid at 298 K and standard pressure.

    (4) NaBr dissolves in H2O at 298 K.

    4

    What is the formula for iron(II) oxide?

    (1) FeO

    (2) FeO2

    (3) Fe2O

    (4) Fe2O3

    5

    Which substance can be broken down by chemical means?

    (1) ammonia

    (2) aluminum

    (3) antimony

    (4) argon

    6

    Which formula represents ammonium nitrate?

    (1) NH4NO3

    (2) NH4NO2

    (3) NH4(NO3)2

    (4) NH4(NO2)2

    7

    What is represented by the chemical formula PbCl2(s)?

    (1) a substance

    (2) a solution

    (3) a homogeneous mixture

    (4) a heterogeneous mixture

    8

    What is the chemical formula for ammonium sulfide?

    (1) (NH4)2S

    (2) (NH4)2SO3

    (3) (NH4)2SO4

    (4) (NH4)2S2O3

    Base your answers to questions 9 on the information below and on your knowledge of chemistry.

    During a laboratory activity, appropriate safety equipment was used and safety procedures were followed. A laboratory technician heated a sample of solid KClO3 in a crucible to determine the percent composition by mass of oxygen in the compound. The unbalanced equation and the data for the decomposition of solid KClO3 are shown below.

    compounds fig: chem62019-exam_g14.png

    9

    Write a chemical name for the compound that decomposed.

    Allow 1 credit for potassium chlorate.

    Base your answers to questions 10 on the information below and on your knowledge of chemistry.

    Thermal energy is absorbed as chemical reactions occur during the process of baking muffins. The batter for muffins often contains baking soda, NaHCO3(s), which decomposes as the muffins are baked in an oven at 200.°C. The balanced equation below represents this reaction, which releases CO2(g) and causes the muffins to rise as they bake. The H2O(ℓ) is released into the air of the oven as it becomes a vapor.

    2NaHCO3(s) + heat → Na2CO3(s) + H2O(ℓ) + CO2(g)

    10

    Based on Table E, identify the polyatomic ion in the solid product of the reaction.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • carbonate ion

    • carbonate

    • CO32−

    Base your answers to questions 11 on the information below and on your knowledge of chemistry.

    A sample of seawater is analyzed. The table below gives the concentration of some ions in the sample.

    compounds fig: chem62015-exam_g15.png

    11

    Write a chemical formula of one compound formed by the combination of K+ ions with one of these ions as water completely evaporates from the seawater sample.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • KCl

    • K2SO4

    Base your answers to questions 12 on the information below and on your knowledge of chemistry.

    Baking soda, NaHCO3, can be commercially produced during a series of chemical reactions called the Solvay process. In this process, NH3(aq), NaCl(aq), and other chemicals are used to produce NaHCO3(s) and NH4Cl(aq).

    To reduce production costs, NH3(aq) is recovered from NH4Cl(aq) through a different series of reactions. This series of reactions can be summarized by the overall reaction represented by the unbalanced equation below.

    NH4Cl(aq) + CaO(s) → NH3(aq) + H2O(ℓ) + CaCl2(aq)

    12

    Write a chemical name for baking soda.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • sodium hydrogen carbonate

    • sodium bicarbonate

    • sodium acid carbonate

    • monosodium carbonate

    • bicarbonate of soda

    Base your answers to questions 13 on the information below and on your knowledge of chemistry.

    One process used to manufacture sulfuric acid is called the contact process. One step in this process, the reaction between sulfur dioxide and oxygen, is represented by the forward reaction in the system at equilibrium shown below.

    2SO2(g) + O2(g) ⇌ 2SO3(g) + 394 kJ

    A mixture of platinum and vanadium(V) oxide may be used as a catalyst for this reaction. The sulfur trioxide produced is then used to make sulfuric acid.

    13

    Write the chemical formula for vanadium(V) oxide.

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • V2O5

    • O5V2

    Base your answers to questions 14 on the information below and on your knowledge of chemistry.

    In the late 19th century, the Hall-Herroult process was invented as an inexpensive way to produce aluminum. In this process, Al2O3(ℓ) extracted from bauxite is dissolved in Na3AlF6(ℓ) in a graphite-lined tank, as shown in the diagram below. The products are carbon dioxide and molten aluminum metal.

    classification-of-matter fig: chem62013-exam_g18.png

    14

    Write the chemical name for the liquid compound dissolved in the Na3AlF6(ℓ).

    Allow 1 credit. Acceptable responses include, but are not limited to:

    • aluminum oxide

    Base your answers to questions 15 on the information below.

    Calcium reacts with water. This reaction is represented by the balanced equation below. The aqueous product of this reaction can be heated to evaporate the water, leaving a white solid, Ca(OH)2(s).

    Ca(s) + 2H2O(ℓ) → Ca(OH)2(aq) + H2(g)

    15

    Write the chemical name of the base produced in the reaction.

    Allow 1 credit for calcium hydroxide.