Name: ______Date Due: ______
Chemistry Homework: Chapters 7.1 and 7.2
1. What is a reactant?
2. What is the function of an arrow in a chemical equation?
3. What is a skeleton equation?
4. Write a skeleton equation for burning sulfur in oxygen to form sulfur dioxide.
5. What is a catalyst?
6. How do you indicate that heat is added to a reaction?
7. Write a skeleton equation for the reaction of potassium chlorate (KClO3) with heat and the catalyst, manganese (IV) oxide (MnO2), to form oxygen gas and another product.
8. What is the other product formed?
9. What does the symbol (s) mean in a chemical reaction?
10. What does the symbol (g) mean in a chemical reaction?
11. What does the symbol (aq) mean in a chemical reaction?
12. How do you indicate that a catalyst is used in a reaction?
13. Write out the following chemical reaction in words rather than in symbols.
H2SO4 (aq) + BaCl2 (aq) ® BaSO4 (s) + HCl (aq)
Laboratory Demonstration
One type of chemical reaction is combustion. In this demonstration, a strip of magnesium is burned in air. Describe what happens. Try to explain the chemical reaction in this demonstration.
Name: ______Date Due: ______
Chemistry Homework: Chapters 7.4 to 7.7
1. What is a balanced equation?
2. Balance the following reactions.
a) KNO3 ® KNO2 + O2
b) Al4C3 + H2O ® CH4 +Al(OH)3
c) Fe(OH)3 ® Fe2O3 +H2O
d) Al2(SO4)3 + Ca(OH)2 ® Al(OH)3 + CaSO4
e) Fe2O3 + CO ® Fe + CO2
7. Rewrite these word equations as balanced chemical equations.
a) Zinc and hydrochloric acid produce zinc chloride and hydrogen gas.
b) Ammonium chloride and calcium hydroxide produce calcium chloride plus ammonia and water.
c) Silver nitrate reacts with sulfuric acid to produce silver sulfate and nitric acid.
10. What is a combination reaction?
11. What type of compound is created when a metallic oxide reacts with water?
12. What is a decomposition reaction?
13. What do most decomposition reactions require in order to occur?
14. Write a balanced chemical reaction (using chemical symbols, not words) for the decomposition reaction of silver (I) oxide with heat.
15. Balance the reactions: KClO3(s) ® KCl(s) + O2(g)
16. NaClO3(s) ® NaCl(s) + O2(g)
Name: ______Date Due: ______
Chemistry Homework: Chapters 7.8 to 7.12
1. What is a single-replacement reaction?
2. What determines whether one metal can replace another metal in a compound?
3. When nonmetals replace other nonmetals, the replacement is usually limited to what group of elements?
4. Write a balanced chemical equation for the following single-replacement reactions.
a) Al(s) + Fe(NO3)2 ® Fe(s) + Al(NO3)3
b) Fe(s) + H2O ® Fe3O4(s) + H2(g)
c) Cl2(g) + KBr(aq) ® KCl(aq) +Br2
7. What is a double-replacement reaction?
8. How are these reactions often characterized?
9. Write a balanced equation for each of these reactions.
a) Pb(NO3)2 (aq) + KI(aq) ® PbI2(s) + KNO3(aq)
b) CuCl2(aq) + Na2S(aq) ® NaCl(aq) + CuS(s)
11. What is a combustion reaction?
12. Balance the following reactions.
C3H8(aq) + O2(g) ® CO2(g) + H2O(g)
13. C6H14(l) + O2(g) ® CO2(g) + H2O(l)
14. What is a complete ionic equation?
15. What are spectator ions?
16. What is a net ionic equation?
17. Write a balanced net equation for: Pb(NO3)2(aq) + H2SO4(aq) ® PbSO4(s) + HNO3(aq)
Name: ______Date Due: ______
Chemistry Homework: Chapter 8 – Stoichiometry 1
1. Balance the following chemical equation and explain how many moles of each reactant form how many moles of product.
CO2(g) + LiOH(s) ® Li2CO3(s) + H2O(l)
2. The above reaction is used in manned spacecraft to scrub carbon dioxide from the craft’s atmosphere. If an astronaut produces 20 moles of CO2 per day, how many grams of lithium hydroxide are needed per astronaut per day?
3. If 6 moles of hydrogen gas are reacted with a sufficient quantity of nitrogen gas, how many moles of ammonia (NH3) are produced?
4. What is the mass of the ammonia produced?
5. At STP, how many liters does this ammonia occupy?
6. When magnesium burns in air, it produces magnesium oxide. If 48.6 grams of magnesium are burned in an open container, how many grams of magnesium oxide are produced?
7. Carbon disulfide is an important industrial solvent produced by reacting coke (carbon) with sulfur dioxide. Write a balanced equation for the reaction
C(s) + SO2 ® CS2(l) + CO(g)
8. If 60 tons of coke is reacted with a sufficient amount of sulfur dioxide, how many tons of carbon disulfide is produced?
9. Joseph Priestly discovered the element oxygen in 1777 by decomposing mercury(II) oxide into its two constituent elements. Write a balanced equation for this reaction.
10. If Priestly used 43.3 grams of mercury(II) oxide, then how many grams of oxygen did he produce?
11. At STP, what volume did the oxygen occupy?
Name: ______Date Due: ______
Chemistry Homework: Chapter 8 – Stoichiometry 2
1. What is a limiting reagent?
2. What is an excess reagent?
3. For the reaction SiO2(s) + 4HF(g) ® SiF4(g) + 2H2O if 2 moles of HF are combined with 4.5 moles of SiO2, then which reactant is the limiting reagent?
For the reaction N2H4(l) + 2H2O2(l) ® N2(g) + 4H2O(g)
4. If 0.75 moles of N2H4 react with 0.5 mole of H2O2, then which is the limiting reagent?
5. How much of the excess reagent is left?
6. How many moles of H2O are produced?
Given the reaction C6H6 + Cl2 ® C6H5Cl + HCl
7. What is the mass of one mole of C6H6?
8. What is the mass of one mole of C6H5Cl?
9. Given 36.8 g of C6H6 and an excess of Cl2, what is the theoretical yield of C6H5Cl?
10. If the actual yield of C6H5Cl is 38.8 g, then what is the percent yield?
catalyst
11. Given the reaction CO(g) + 2H2(g) ¾¾® CH3OH(l). If 75 g of CO reacts to produce 68.4 g of CH3OH, what is the percent yield?
Name: ______Date Due: ______
Chemistry Homework: Chapter 8 – Stoichmetry 3
Given the chemical reaction Na2CO3 + Ca(OH)2 ® 2NaOH + CaCO3
1. Determine to two decimal places the molar masses of all 4 substances involved.
Iron (III) hydroxide and sulfuric acid react through the following double
displacement reaction: Fe(OH)3 + H2SO4 ® Fe2(SO4)3 + H2O
2. Balance the equation.
3. If 5 moles of Fe (OH)3 react, how many moles of H2SO4 are required?
4. What mass in grams of H2SO4 is this?
Sulfuric acid reacts with sodium hydroxide by the reaction
H2SO4 + NaOH ® Na2SO4 + H2O
5. Balance the equation.
6. What mass of H2SO4 would be required to react with 0.75 moles of NaOH?
Baking soda (NaHCO3) reacts with cream of tartar (KHC4H4O6) by the reaction
NaHCO3 + KHC4H4O6 ® KNaC4H4O6 + CO2 + H2O
7. If a recipe calls for 2 teaspoons or 8 g of cream of tartar, how many moles of baking soda are needed?
8. What mass of each product is formed?
9. Given the decomposition reaction CaCO3(s) ® CaO(s) + CO2(g) If 25.4 g
of CaCO3 react to produce 13.2 g of CaO, what is the percent yield of CaO?
10. Why are actual yields generally less than those calculated theoretically?
11. Given the reaction 2Al + 3Cl2 ® 2AlCl3 If we are given 3.6 moles of Al and 5.3
moles of Cl2, which is the limiting reagent?
12. Given the reaction 8Zn(s) + S8(s) ® 8ZnS(s). If 2 moles of zinc are heated with 1 mole of S8, which is the limiting reagent?
Name: ______Date Due: ______
Chemistry Homework: Chapter 9.1 and 9.2, The States of Matter 1
1. What is the energy an object has because of its motions?
2. What is between the particles of a gas?
3. How do particles in a gas move?
4. What portion of an empty space would a gas occupy?
5. Why don't gas particles travel great distances in the Earth's atmosphere?
6. What does "perfectly elastic" mean?
7. What is gas pressure?
8. What instrument do we commonly use to measure atmospheric pressure?
9. What is the SI unit of pressure?
10. Define a pascal (hint: your book doesn't tell you)
11. Why did mercury rise 760 mm up an early barometer?
12. What is the pressure of one torr?
13. If mercury has a density of 13.6 g/cm3, how many inches would a column of water rise in an early barometer?
14. Convert 190 mm of mercury into atmospheres of pressure.
15. Convert 506.5 kPa into atmospheres of pressure.
Name: ______Date Due: ______
Chemistry Homework: Chapter 9.3 - 9.6, The States of Matter 2
1. In what two ways are the curves in figure 9.5 of your text different?
2. At what temperature does the motion of particles theoretically cease?
3. What is the difference between the Kelvin and Celsius temperature scales?
4. How is the Kelvin temperature of an object related to its average kinetic energy?
5. If a gas is heated from 200K to 800K, how much does the average kinetic energy of the gas particles change?
6. Define evaporation.
7. Why do liquids evaporate faster when heated?
8. Why is evaporation a cooling process?
9. Define vapor pressure.
10. What is a dynamic equilibrium?
11. Why do the inner walls of a sealed terrarium sweat?
12. Define boiling point.
13. When water boils, bubbles form and rise to the surface of the liquid. What gas is contained within the bubbles?
14. How does pressure affect boiling points?
15. Examine figure 9.12 of your text. At what temperature would ethanol boil in Denver?
16. What happens to the temperature of a pure liquid as it boils?
Name: ______Date Due: ______
Chemistry Homework: Chapter 9.7 - 9.8, The States of Matter 3
1. What do the atoms of a solid tend to vibrate about?
2. What happens when you heat a solid?
3. What happens at the melting point of a solid?
4. Why do ionic solids generally have high melting temperatures?
5. What defines a crystal?
6. What is a unit cell?
7. Which of the seven crystal classes has the most symmetry?
8. Which of the seven crystal classes has the least symmetry?
9. What is the difference between a body-centered and a face-centered cubic unit cell?
10. What are allotropes?
11. Examine Figure 9.18 of your text. Explain why graphite is so much softer than diamond although both are composed of pure carbon.
12. What are amorphous solids?
13. What do glasses do instead of melting at a particular temperature?
14. If shattered, what is the difference between a crystalline solid and an amorphous solid?
15. What are liquid crystals?
16. What is sublimation?
Name: ______Date Due: ______
Chemistry Homework: Chapter 9.9 - 9.10, The States of Matter 4
1. What is a phase diagram?
2. What does the line on a phase diagram between the solid and liquid region represent?
3. What does the line on a phase diagram between the liquid and gas region represent?
4. What is unique about the triple point?
Examine the following phase diagram for carbon dioxide.
Pressure liquid
in solid
Atmospheres
gas
5. What are the conditions of temperature and pressure at the triple point?
6. At what temperature does solid carbon dioxide sublime in our classroom?
7. What must be true in order for CO2 to exist in the liquid phase?
8. What is a plasma?
9. At what temperatures is the material of the stars?
10. From the lecture. What happens at the critical point of a substance?
Name: ______Date Due: ______
Chemistry Homework: Chapter 10.1 - 10.5 Thermochemistry
1. Define chemical potential energy.
2. What is thermochemistry?
3. Define a calorie.
4. Define a Calorie.
5. Define heat capacity.
6. Define specific heat capacity.
7. Which common substance has the highest specific heat capacity?
8. What, in a thermodynamic sense, is the universe?
9. What is an exothermic process?
10. What is an endothermic process?
11. What is a calorimeter?
12. Define calorimetry.
13. What is enthalpy?
Given the formula: q = mcDT Memorize this equation!
Where q = heat, m = mass, c = heat capacity and DT = the change in temperature.
14. How much heat is needed to raise the temperature of 150-g of water 25°C?
Name: ______Date Due: ______
Chemistry Homework: Chapter 10.6 Thermochemical Equations
1. What is a thermochemical equation?
2. Why is it important to state that a thermochemical reaction occurred in the open at one atmosphere of pressure?
3. What is the meaning of "their usual physical states?"
4. What is the sign convention for DH?
5. Is H2O(g) ® H2(g) + 1/2 O2(g) a proper thermochemical equation?
6. Define heat of combustion.
7. Explain whether the diagram below shows an exothermic or endothermic reaction.
Enthalpy (H)
Course of reaction
8. Examine Table 10.5 in your text on page 273. Explain why the DH of the standard heats of combustion becomes increasingly negative as the number of carbon atoms of the substance increases.
9. Magnesium burns in air by the following reaction: 2Mg(s) + O2(g) ® 2MgO(s) + 1204 kJ. How many kilojoules of energy are given off when 6.55 g of Mg reacts with an excess of oxygen?
Name: ______Date Due: ______
Chemistry Homework: Chapter 10.8 Hess's Law
Questions 1 and 2 are worth 1 point each, 3 and 4 are worth 5 points each.
1. If you were crazy, and wanted to change a diamond into graphite, but didn't want to wait millions of years for the reaction to naturally take place, how could you speed up the process?
2. Does the number of intermediate steps make any difference in how much energy is needed to go from a given set of reactants to a given set of products?
3. Let's say that we want to know the heat of reaction of decomposing water ice into hydrogen and oxygen. This reaction can be expressed as:
H2O(s) ® H2(g) + 1/2O2(g) DH = ?
Given the following reactions, calculate the desired value for DH.
H2(g) + 1/2 O2(g) ® H2O(l) DH°f = -285.9 kJ