# Chapter 4: Chemical Quantities and Aqueous Reactions

## 4.2 Reaction Stoichiometry: How Much Carbon Dioxide

1. Introduction
1. Meaning
2. Calculation of reactants and products
3. Limiting Reagents

2. P4 (s) + 6 Cl2 (g) -> 4 PCl3 (l) (5-2)
1. Animation, molecular level ( Internet© Saunders, 1997)
2. Video, number of moles ( Internet© Saunders, 1997)
3. Calculate the mass of phosphorous trichlorided produced when 0.01 moles of P4 reacts with 0.06 moles of chlorine gas.

## 4.3 Limiting Reactant, Theoretical Yield, and Percent Yield

1. Zn (s) + 2 HCl (g) -> Zn2+ (aq) + H2 (g) + 2 Cl1- (aq)
1. Limiting Reagent Video ( Internet© Saunders, 1997)

2. Example Problem

2. 10.0 grams of hydrogen gas reacts with 10.0 grams of oxygen gas to produce water.
1. determine the limiting reagent
2. calculate the final mass
3. If only 10.58 g of H2O is produced, what is the percent yield?

3. Solid Rocket fuel used for the space shuttle is aluminum metal and ammonium perchlorate. These react to produce aluminum oxide, aluminum chloride, nitrogen monoxide, and water. Solid Rocket Booster Separation
1. Write out the chemical equation
2. Balance the chemical equation
3. Given 1.00 kg each reactant, which is limiting, what is the mass of each product.
4. Given 1.00 kg Al, how much NH4ClO4 should be used. What is the mass of products?

4. Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel rocket motors. (video clip). What masses of iron(III) oxide and aluminum are required for a theoretical yield of 15.0 g iron? What is the maximum mass of aluminum oxide that could be produced? How much aluminum oxide is actually produced from these starting materials if the yield is 93%? The thermite reaction is:
5. Fe2O3(s) + 2Al(s) -> 2Fe(l) + Al2O3(s)

6. Elixirs such as Alka-Seltzer use the reaction of sodium bicarbonate with citric acid in aqueous solution to produce a fizz. Balance the following reaction.
1. What mass of C6H8O7 should be used for every 1.0*102 mg of NaHCO3?
2. If 1.0*102 mg of C6H8O7 is used, which is the limiting reagent?
3. What mass of CO2(g) could be produced by this mixture?
4. If only 45 mg of CO2 is produced, what is the percent yield?
5. How many grams of Na3C6H5O7 is actually produced?

## 4.4 Solution Concentration and Solution Stoichiometry

1. Introduce Concentration and Molarity
2. Preparing a solution of NiCl2*6H2O ( internet)
1. 8.320g NiCl2*6H2O
3. How to produce 500.0 mL of 0.0100 M K2Cr2O7 (aq)
4. How do you prepare 100 mL of 0.150 M caffeine (C8N4O2H10)?
5. How do you prepare 1.50 L of 3 M Mg2+ from Magnesium nitrate?
6. 0.100 M K2Cr2O7 2.00 mL diluted to 500 mL ( internet )

7. 0.140 M NiCl2 (aq) solution
1. Dilute 2.00 mL to 500 mL
2. Dilute 5.00 mL to 500 mL
3. Dilute 5.00 mL to 250 mL
4. Dilute 5.00 mL to 1.00 L

## 4.5 Types of Aqueous Solutions and Solubility

• Ions in Solution
1. Structure of Ionic Compounds (overhead fig 3.13)
2. Solvation of Ionic Compounds (overhead fig 3.15)
3. KMnO4 ( , Internet© Saunders, 1997)
4. Strong and Weak Acids & Bases, CD-ROM 4-7 & 4-8 (overhead table 4.1)

## 4.6 Precipitation Reactions

K2CrO4 (aq) + Pb(NO3)2 (aq) - > PbCrO4 (s) + 2 KNO3 (aq)

Pb(NO3)2 (aq) + 2 KI (aq) -> PbI2 (s) + 2 KNO3 (aq)

3. silver nitrate and sodium chloride produces silver chlroide and sodium nitrate( Internet© Saunders, 1997)
AgNO3 (aq) + NaCl aq) - > AgCl (s) + NaNO3 (aq)

4. iron (III) Ions + Sodium hydroxide produces iron (iii) hydroxide and sodium ions( Internet)
Fe3+ (aq) + 3 NaOH (aq) - > Fe(OH)3 (s) + 3 Na1+(aq)

5. Solubility Rules

## 4.8 Acid-Base and Gas-Evolution Reactions

1. Definitions of acids and bases
1. Arrhenius definition (in water only)
1. Acids, produce H+ in water solution: HCl (aq) -> H+(aq) + Cl-
2. Bases, produce OH- in water solution: NaOH(aq) -> Na+ + OH-

2. Bronsted-Lowry Acids and bases (more general definition)
1. Acids are proton donors in a chemical reaction
1. HCl (g) + H2O -> H3O+ + Cl-
2. Acid + Base -> Base + Acid
2. Bases are proton acceptors in a chemical reaction
1. NaOH + H2O -> Na+ + H3O+
2. Base + Acid -> Acid + Base

2. Common Acids (know names of all strong acids)
1. Monoprotic - Single H+
2. Polyprotic - more than 1 H+, ie: diprotic, triprotic
1. H2SO4 + H2O -> H3O1+ + HSO41-
2. HSO41- + H2O -> H3O1+ + SO42-
3. Strong acids (dissociate completely)
4. Weak acids (partially dissociate, introduce equlibrium)

3. Common Bases
1. Strong Bases (alkali metal hydroxides)
2. Weak bases (ammonia)

4. Aqueous Acid-Base Reactions
1. Total Equation: HCl(aq) + NaOH(aq) -> H2O(l) + NaCl(aq)

2. Ionic Equations
1. Dissociation
1. HCl (g) -> H+(aq) + Cl-(aq) OR HCl(g) + H2O(l) -> H3O+(aq) + Cl-(aq)
2. NaOH -> Na+(aq) + OH-(aq)
2. Neutralization (spectator ions): H3O+ + Cl- + Na+ + OH- -> 2 H2O + Na+ + Cl-

3. Net Ionic Equation: H3O+ + OH- -> 2 H2O

5. Example Reactions
1. Magnesium Hydroxide + Nitric Acid
1. Total equation
2. Ionic Equation
3. Net ionic equation

2. Sulfuric acid and lithium hydroxide
1. Total equation
2. Ionic Equation
3. Net ionic equation

3. Acetic acid and iron (III) hydroxide
1. Total equation
2. Ionic Equation
3. Net ionic equation

4. Ammonia (NH3) and water( Internet)
5. hydrochloric acid and ammonia produces ammoinum and chloride
6. hydrochloric acid and sodium hydroxide produces sodium chloride and water; no indicator