Mr Gentry's Mad Science: AP Chem Balanced Equations and Chemical Reactions

AP Chemistry

Equations and Balancing Equations

Homework and Discussions for the week of 3.

1. Further Reading Into Chemical Equations

2. Explanation by Kahn Academy, Balancing Equation

3. Practice Game

4. Another Practice Game

Concepts to review and answer as you go through this material:

Reviewing Concepts

Identify the reactants and products in each chemical reaction.
1. In photosynthesis, carbon dioxide and water react to form glucose and oxygen.
2. Magnesium oxide forms when magnesium is exposed to oxygen gas.
What is the relationship between an equal sign and a yield sign?
Write sentences that completely describe the chemical reactions shown in the skeleton equations below.
1. $\text{H}_2\text{O}_2(l) \overset{\text{MnO}_2}{\rightarrow} \text{H}_2\text{O}(l) + \text{O}_2(g)$
2. $\text{CuCO}_3(s) \overset{\Delta}{\rightarrow} \text{CuO}(s) + \text{CO}_2(g)$
3. $\text{Cs}(s) + \text{H}_2\text{O}(l) \rightarrow \text{CsOH}(aq) + \text{H}_2(g)$
How many atoms of each element are represented by the following combinations of coefficients and chemical formulas?
1. 5Br₂
2. 2NH₃
3. 4(NH₄)₂SO₄
4. 2CH₃COOH
5. 3Fe(NO₃)₃
6. 2K₃PO₄
The skeleton equation for the reaction of nitrogen gas with oxygen gas to form dinitrogen monoxide is shown below. Explain why the equation below is not a correctly balanced equation for this reaction.

Problems

Balance each of the following equations.
1. KClO₃ → KCl + O₂
2. Ca(OH)₂ + HBr → CaBr₂ + H₂O
3. C₄H₁₀ + O₂ → CO₂ + H₂O
4. NH₃ + CuO → Cu + N₂ + H₂O
Write and balance chemical equations for each of the following word equations.
1. sodium carbonate → sodium oxide + carbon dioxide
2. tetraphosphorus decoxide + water → phosphoric acid
3. lead + nitrogen → lead(II) nitride
4. ammonium carbonate → ammonia + water + carbon dioxide
Write and balance chemical equations from the following descriptions. Include symbols for the physical states of each reaction component.
1. Solid barium oxide is reacted with water and forms aqueous barium hydroxide.
2. Aqueous lithium phosphate reacts with aqueous iron(III) nitrate to form aqueous lithium nitrate and solid iron(III) phosphate.
3. Aluminum metal is reacted with an aqueous solution of zinc chloride to form aqueous aluminum chloride and solid zinc.
4. Iron(III) oxide solid reacts with carbon monoxide gas to produce iron and carbon dioxide gas.
The following equations are incorrect in some way. Identify and correct each error, and then balance the corrected equation.
1. K + O₂ → KO₂
2. Ag₂O → Ag₂ + O
3. NaCl + F₂ → NaF₂ + Cl
Reviewing Concepts
Write a general reaction for each reaction type below.
1. double-replacement
2. decomposition
3. single-replacement
4. combination
Which type of reaction generally takes place only between substances in aqueous solution?
What do all combustion reactions have in common?
Where on an activity series are the most reactive elements located?
Classify the following reactions according to the five basic reaction types.
1. Cd(s) + H₂SO₄(aq) → CdSO₄(aq) + H₂(g)
2. 2Fe(s) + 3Cl₂(g) → 2FeCl₃(s)
3. C₇H₈(l) + 9O₂(g) → 7CO₂(g) + 4H₂O(g)
4. 2NH₄NO₃(s) → 2N₂(g) + O₂(g) + 4H₂O(g)
5. 2CoCl₃(aq) + 3Pb(NO₃)₂(aq) → 2Co(NO₃)₃(aq) + 3PbCl₂(s)

Problems

15. Write balanced chemical equations for the following combination reactions.

1. Sr(s) + S(s) →
2. Zn(s) + O₂(g) →
3. Li₂O(s) + H₂O(l) →
Write balanced chemical equations for the following decomposition reactions.
1. $\text{Na}_3\text{N}(s) \overset{\Delta}{\rightarrow}$
2. $\text{SnCO}_3(s) \overset{\Delta}{\rightarrow}$
3. $\text{NCl}_3(l) \rightarrow$
4. $\text{Mg(OH)}_2(s) \overset{\Delta}{\rightarrow}$
Use the activity series to write a balanced chemical equation for the following single-replacement reactions. Write NR if no reaction occurs.
1. Cl₂(g) + NaF(aq) →
2. Ca(s) + H₂O(l) →
3. Pt(s) + H₂SO₄(aq) →
4. Al(s) + NiBr₂(aq) →
Write balanced chemical equations for the following double-replacement reactions.
1. Ca(NO₃)₂(aq) + K₃PO₄(aq) → (calcium phosphate precipitates)
2. HI(aq) + Mg(OH)₂(aq) →
3. FeS(s) + HCl(aq) → (aqueous iron(II) chloride is one product)
4. CuBr₂(aq) + KOH(aq) → (copper(II) hydroxide precipitates)
5. 20.Write balanced equations for the combustion of the following compounds.
1. ethyne (C₂H₂)
2. acetic acid (CH₃COOH)
3. hexane (C₆H₁₄)