5.12: End of Chapter Problems
Chemical Reactions
1. Which of the following is a chemical reaction?
- Freezing liquid Mercury.
- Adding yellow to blue to make green.
- Cutting a piece of paper into two pieces.
- Dropping a sliced orange into a vat of sodium hydroxide.
- Filling a balloon with natural air.
- Painting a wall blue
- A bicycle rusting
- Ice cream melting
- Scratching a key across a desk
- Making a sand castle
2. Which of the following is not a chemical reaction?
- Shattering glass with a baseball
- Corroding Metal
- Fireworks exploding
- Lighting a match
- Baking a cake
- Frying an egg
- Slicing carrots
- A macbook falling out of a window
- Creating ATP in the human body
- Dropping a fizzy tablet into a glass of water
Balancing and Classifying Chemical Equations
1. Balance the following chemical equations.
- Hg(ℓ)+O 2 (g)→HgO(s)
- C 2 H 4 (g)+O 2 (g)→CO 2 (g)+H 2 O(g)
- Mg(NO 3 ) 2 (s)+Li(s)→Mg(s)+LiNO 3 (s)
- N 2 (g)+O 2 (g)→NO 2 (g)
- Pb(NO 3 ) 2 (aq)+FeCl 3 (aq)→Fe(NO 3 ) 3 (aq)+PbCl 2 (s)
- C 6 H 14 (l)+O 2 (g)→CO 2 (g)+H 2 O(g)
- C 7 H 16 (l)+O 2 (g)→CO 2 (g)+H 2 O(g)
- C 8 H 18 (l)+O 2 (g)⟶CO 2 (g)+H 2 O(g)
- Pb(NO 3 ) 2 (aq)+NaCl(aq)→NaNO 3 (aq)+PbCl 2 (s)
- KNO 3 (s) → KNO 2 (s) + O 2 (g)
- SiO 2 (s) + HF(aq) → SiF 4 (aq) + H 2 O(l)
- SO 2 + O 2 → SO 3
- NO + O 2 → NO 2
- K + Cl 2 → KCl
- CH 4 + Cl 2 → CH 2 Cl 2 + HCl
- Al + CuO → Al 2 O 3 + Cu
- Mg + P 4 → Mg 3 P 2
- CaCl 2 + AgNO 3 → AgCl + Ca(NO 3 ) 2
- (NH 4 ) 2 SO 4 + CaBr 2 → NH 4 Br + CaSO 4
- Cl 2 + NaBr → NaCl + Br 2
- BiCl 3 + H 2 O → Bi 2 O 3 + HCl
2. Classify each reaction in question 1. Your choices are addition, decomposition, single replacement, double replacement, and combustion reactions.
3. The oxyacetylene torch used for welding burns acetylene gas (C 2 H 2 ). Balance the equation for the incomplete combustion of acetylene.
C 2 H 2 (g) + O 2 (g) → CO(g) + H 2 O(g)
4. One source of acid rain is the addition reaction between sulfur dioxide, oxygen, and water to form sulfuric acid (H 2 SO 4 ). Balance the equation for this reaction.
SO 2 (g) + O 2 (g) + H 2 O (g) → H 2 SO 4 (aq)
Reactions with water
Draw the product of each of the following reactions. Classify each reaction. Your choices are hydration, dehydration, or hydrolysis.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Classification of Alcohols
Identify each alcohol as being 1 o , 2 o , or 3 o .
Oxidations and Reductions
1. One of the reactions used to develop photographic film is shown below. Hydroquinone, a developer reacts with silver ions to form silver metal, which gives the black color in a film negative.
- Is hydroquinone oxidized or is it reduced?
- What is the function of Ag + in this reaction?
- What is the reducing agent? (Hydroquinone or Ag + )
2. The toxic effects of methanol (CH 3 OH) are due to its enzymatic conversion into formaldehyde (CH 2 O) in the liver.
a. In this reaction is methanol oxidized or reduced?
b. Identify the oxidizing agent.
3. To which reaction types do the following reactions belong? You may choose from oxidation or reduction. Identify the agent and the catalyst. Identify the functional group/class in the reactant and product.
a.
b.
c.
d.
e.
f.
g.
Heat of Reaction
1. Label each reaction below as exothermic or endothermic? What is the ΔH of the reaction?
a. CH 4 (g) + 2O 2 (g) → CO 2 (g) + 2H 2 O(ℓ) + 213 kcal
b. N 2 (g) + O 2 (g) + 45 kcal → 2NO(g)
c. H 2 (g) + F 2 (g) → 2HF (g) + 130 kcal
d. 2C(s) + H 2 (g) + 5.3 kcal → C 2 H 2 (g)
2. Draw energy diagrams for reactions 1a & b. Label the x- and y-axis, reactant, products, E a and ΔH.
3. What is a catalyst?
4. One of the enzyme-catalyzed reactions involved in step 1 of the citric acid cycle is the conversion oxaloacetate to citrate. The word equation for the reaction is shown below.
Oxaloacetate + Acetyl-CoA + H 2 O → Citrate + CoA + 3.3 kcal
Answer the following questions based on this reaction.
a. What is the value for ∆H for the reaction?
b. Is the reaction exothermic or endothermic?
c. How would you expect decreasing the concentration of oxaloacetate to affect the reaction rate?
d. How would removing the enzyme affect the reaction rate?
e. The normal body temperature is around 98 o F. How would the reaction rate be affected if the person suffered hypothermia?