Chemistry HW 13

Which of the following are combustion reactions? 1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l) 2) CaO (s) + CO2 (g) → CaCO3 (s) 3) PbCO3 (s) → PbO (s) + CO2 (g) 4) CH3OH (l) + O2 (g) → CO2 (g) + H2O (l)

1 and 4

Write the balanced equation for the reaction that occurs when methanol, CH3OH (l), is burned in air. What is the coefficient of methanol in the balanced equation?

2

Part D When solid mercury(II) nitrate is heated, it decomposes to form solid mercury(II) oxide, gaseous nitrogen dioxide, and oxygen.

2Hg(NO3)2(s)→2HgO(s)+4NO2(g)+O2(g)

Part B When solid potassium chlorate is heated, it decomposes to form solid potassium chloride and oxygen gas.

2KClO3(s)→2KCl(s)+3O2(g)

Part E When hydrogen sulfide gas is passed over solid hot iron (III) hydroxide, the resultant reaction produces solid iron (III) sulfide and gaseous water.

3H2S(g)+2Fe(OH)3(s)→Fe2S3(s)+6H2O(g)

Part C Phosphine, PH3(g), combusts in oxygen gas to form water vapor and solid tetraphosphorus decaoxide.

4PH3(g)+8O2(g)→6H2O(g)+P4O10(s)

What is the coefficient of O2 when the following equation is completed and balanced? C4H8O2 + O2 → ________

5

Which one of the following substances is the product of this combination reaction? Al (s) + I2(s) → ________

AlI3

Part B Boron sulfide, B2S3(s), reacts violently with water to form dissolved boric acid (H3BO3) and hydrogen sulfide gas.

B2S3(s)+6H2O(l)→2H3BO3(aq)+3H2S(g)

Part C. Give the balanced chemical equation (including phases) that describes the combustion of butene, C4H8(g). Indicate the phases using abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively.

C4H8(g)+6O2(g)→4H2O(g)+4CO2(g)

Part A Solid calcium carbide, CaC2, reacts with water to form an aqueous solution of calcium hydroxide and acetylene gas, C2H2.

CaC2(s)+2H2O(l)→Ca(OH)2(aq)+C2H2(g)

Part A. Classify each of the following reactions: A. C3H8(g)+5O2(g)→3CO2(g)+4H2O(g) B. 2KClO3(s)→2KCl(s)+3O2(g) C. H2(g)+I2(g)→2HI(g) D. MgO(s)+CO2(g)→MgCO3(s) E. 2N2O5(g)→4NO2(g)+O2(g)

Decomposition: E B Combination: C D Combustion: A

Of the reactions below, which one is a decomposition reaction?

NH4Cl → NH3 + HCl

When a hydrocarbon burns in air, a component produced is ________.

water

Of the reactions below, which one is not a combination reaction?

2CH4 + 4O2 → 2CO2 + 4H2O

Part B. Solid lithium metal and diatomic fluorine gas react spontaneously to form a solid product. Give the balanced chemical equation (including phases) that describes this reaction. Indicate the phases using abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively.

2Li(s)+F2(g)→2LiF(s)

Which of the following are decomposition reactions? 1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l) 2) CaO (s) + CO2 (g) → CaCO3 (s) 3) Mg (s) + O2(g) → MgO (s) 4) PbCO3 (s) → PbO (s) + CO2 (g)

4 only

Part E Copper metal reacts with hot concentrated sulfuric acid solution to form aqueous copper(II) sulfate, sulfur dioxide gas, and water.

Cu(s)+2H2SO4(aq)→CuSO4(aq)+SO2(g)+2H2O(l)

Part D. When heated, solid copper(II) carbonate decomposes to solid copper(II) oxide and carbon dioxide gas. Give the balanced chemical equation (including phases) that describes this reaction. Indicate the phases using abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively.

CuCO3(s)→CuO(s)+CO2(g)

Part D When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid, H3PO3(aq), and aqueous hydrochloric acid.

PCl3(l)+3H2O(l)→H3PO3(aq)+3HCl(aq)

In a combustion reaction:

Hydrocarbons react with O2 to produce carbon dioxide and water.

Part A When sulfur trioxide gas reacts with water, a solution of sulfuric acid forms.

SO3(g)+H2O(l)→H2SO4(aq)

Part C Solid zinc metal reacts with sulfuric acid to form hydrogen gas and an aqueous solution of zinc (II) sulfate.

Zn(s)+H2SO4(aq)→H2(g)+ZnSO4(aq)

When a hydrocarbon burns in air, what component of air reacts?

oxygen