Chemistry - Chapter 11 - Chemical Reactions
What is the law of conservation of mass?
In any chemical change, mass is conserved.
Sulfur burns in oxygen to form sulfur dioxide. Write a skeletal equation for this chemical reaction. Include appropriate symbols from 11.1 (p.323)
S(s) + O₂(g) → SO₂(g)
What reaction is this? A chemical change in which one element replaces a second element in a compound.
Single-Replacement Reaction.
What are coefficients?
small whole numbers that are placed in front of the formulas in an equation in order to balance it.
Complete and balance this decomposition reaction. HI ----->
2HI -----> H↓2 + I↓2
A block of ice measures 25.0 cm x 42.0 cm x 38.0 cm. What is the mass of the ice in kilograms? The density of ice is 0.917 g/cm³.
36.6 kg
What does the arrow ( →) in a word equation mean?
"Yields," separates reactants from products.
Name the reaction. A chemical change in which an element or a compound reacts with oxygen often producing energy in the form of heat and light. This reaction always involves oxygen as a reactant. Often the other reactant is a hydrocarbon, which is a compound composed of hydrogen and carbon.
A Combustion Reaction.
What is a spectator ion?
An ion that appears on both sides of an equation and is not directly involved in the reaction.
Write and balance this equation. calcium hydroxide + sulfuric acid -----> calcium sulfate + water
Ca(OH)↓2 + H↓2SO↓4 -----> CaSO↓4 + 2H↓2O
Name the equation. An equation that shows dissolved ionic compounds as dissociated free ions.
Complete Ionic Equation.
Write the complete ionic equation and net ionic equation for the reaction of aqueous calcium hydroxide with phosphoric acid. The products are calcium phosphate and water.
Complete ionic equation: 3Ca²⁺(aq) + 6OH⁻(aq) + 6H⁺(aq) + 2PO₄³⁻(aq) →Ca(PO₄)₂(s) + H₂O(l); net ionic equation:same as complete ionic equation.
How would you write a word equation for the manufacture of bicycles?
Frame + Wheel + Handlebar + pedal (reactants) → bicycle (product)
Write the balanced net ionic equation for this reaction. Ca²(aq) + OH⁻(aq) + H+(aq) + PO₄³⁻(aq) -→ Ca²+(aq) + PO₄³⁻(aq) + H₂O(l)
H+(aq) + OH-(aq) -----> H₂O(l)
Write the formula for the binary compound that decomposes to the products H↓2 and Br↓2.
HBr
What is a spectator ion?
an ion that does not participate in the reaction
The 5 general types of reaction are ....?
1. Combination. 2. Decomposition. 3. Single-Replacement. 4. Double-Replacement. 5. Combustion. Not all reactions fit into one category.
What's the percentage of water on ... 1. Earth 2. Human Body
1. Earth - 70% 2. Human Body - 66%
To add more information to the equation, you can indicate the physical states of substances by putting a symbol after each formula. What do the following symbols stand for? 1. (S) 2. (l) 3. (g) 4. (aq)
1. Solid 2. Liquid 3. Gas 4. Aqueous Solution (a substances dissolved in water)
Describe chemical reactions steps.
1. To write a word equation, write the names of the reactants to the left of the arrow separated by plus signs; write the names of the products to the right of the arrow, also separated by plus signs. 2. To write a skeleton equation, write the formulas for the reactants to the left of the yields sign and the formulas for the products to the right. 3. After writing the skeleton equation, use coefficients to balance the equation so that it obeys the law of conservation of mass.
What is the reaction of aqueous solutions of silver nitrate with sodium chloride to form solid silver chloride and aqueous sodium nitrate?
A double-replacement reaction.
True or False. A net ionic equation shows only those particles involved in the reaction and is balanced with respect to both mass and charge.
True.
True or False. You can predict the formation of a precipitate by using the general rules for solubility of ionic compounds.
True.
True or false. In a combination reaction, there is ALWAYS a single product?
True.
Write a sentence that describes this chemical reaction. Na(s) + H₂O(l) → NaOH (aq) + H₂(g)
When solid sodium is dropped into water, hydrogen gas and aqueous sodium hydroxide are produced.
Can a skeleton equation already be balanced?
Yes. For example, carbon burns in the presence of oxygen to produce carbon dioxide. This equation is balanced. One carbon atom and two oxygen atoms are on each side of the equation. You do not need to change the coefficients; they are all understood to be 1.
Balance each equation. a. FeCl↓3 + NaOH -----> Fe(OH)↓3 + NaCl b. CS↓2 + Cl↓2 -----> CCl↓4 + S↓2Cl↓2
a. FeCl↓3 + 3NaOH -----> Fe(OH)↓3 + 3NaCl b. CS↓2 + 3Cl↓2 -----> CCl↓4 + S↓2Cl↓2
Complete and balance this equation for a combination reaction. Be + O↓2 ----->
2Be + O↓2 -----> 2BeO
Write and balance the equation for the formation of magnesium nitride (Mg↓3N↓2) from its elements.
3Mg + N↓2 -----> Mg↓3N↓2
What is a catalyst?
A substance that speeds up the reaction, but is not used up in the reaction. A catalyst is neither a reactant nor a product, so its formula is written above the arrow in a chemical equation.
Write a balanced equation for the complete combusion of glucose (C₆H₁2O₆)
C₆H₁2O₆ + 6O₂ -----> 6CO₂ + 6H₂O
Many coffees and colas contain the stimulant caffeine. The percent composition of caffeine is 49.5% C, 5.20% H, 16.5% O, and 28.9% N. What is the molecular formula of caffeine if its molar mass is 194.1 g/mol?
C₈H₁₀O₂N₄
How did John Dalton explain a chemical reaction using his atomic theory?
Dalton said that the atoms of reactants are rearranged to form new substances as products.
True or False. The number of elements and/or compounds reacting is a bad indicator of possible reaction type and thus possible products.
False. The number of elements and/or compounds reacting is a GOOD indicator of possible reaction type and thus possible products.
What is a decomposition reaction?
It is a chemical change in which a single compound breaks down into two or more simpler products. It involves only one reactant and two or more products.
What is a combination, or synthesis reaction?
It is a chemical change in which two or more substances react to form a single new substance.
How do you write a balanced chemical equation?
It is a two step process. First, write the skeleton equation. Then, use coefficients to balance the equation so that it obeys the law of conservation of mass.
What is a net ionic equation?
It is an equation for a reaction in solution that shows only those particles that are directly involved in the chemical change.
What does the activity series of metals do?
It lists metals in order of decreasing reactivity.
What did John Dalton's atomic theory state?
It stated that as reactants are converted to products, the bonds holding the atoms together are broken and new bonds are formed.
A fire has 3 requirements. What are they?
Oxygen, Fuel, and a temperature high enough to initiate and sustain combustion.
What is the Environmental Protection Agency or EPA's job?
They are specialists responsible for the safe handling, treatment, storage, and transportation of hazardous materials.
Spectator comes from the latin verb spectare, meaning what?
To watch. Thus a spectator ion can be thought of as only watching a reaction, not participating.
What is the first step in writing a complete chemical equation?
To write the skeletal equation. Write the formulas of the reactants to the left of the yields sign (arrow ----->) and the formulas of the products to the right.
What about the equation for the reaction of hydrogen gas and oxygen gas? Already balanced?
When hydrogen and oxygen are mixed, a spark will initiate a rapid reaction. The product of the reaction is water. See pic. The formulas for all the reactants are product are correct, but this equation is not balanced. Count the atoms on both sides of the equation. Two oxygen atoms are on the reactant (left) side of the equation and only one oxygen atom is on the product (right) side. As written, the equation does not obey the law of conservation of mass and so it does not describe what really happens.
What is a Double-Replacement Reaction?
a chemical change involving an exchange of positive ions between two compounds. Double-replacement reactions are also referred to as double-displacement reactions. They generally take place in aqueous solution and often produce a precipitate, a gas, or a molecular compound such as water.
What is a skeleton equation?
a chemical equation that does not indicate the relative amounts of reactants and products.
These photos (see photos on p. 349 - question 71) show various types of reactions. 1. Aluminum reacting with bromine. 2. The reaction of copper with aqueous silver nitrate. 3. Propane (C₃H₈) reacting with oxygen. 4. The reaction of lead (II) nitrate with potassium iodide. a. Identify each type of reaction. b. Write the equation for each reaction.
a. 1. Combination 2. Single-replacement 3. Combustion. 4. Double-replacement b. 1. (1) 2A1(s) + Br₂(l) → 2A1Br₃(s); 2. (2) Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s); 3. C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g); 4. Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq)
Write electron configurations for the following ions. a. Sr²⁺ b. S²⁻ c. Ga³⁺ d. Cu⁺
a. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶ b. 1s²2s²2p⁶3s²3p⁶ c. 1s²2s²2p⁶3s²3p⁶3d¹⁰ d. 1s²2s²2p⁶3s²3p⁶3d¹⁰
Calculate the number of moles in each substance. a. 54.0 L of nitrogen dioxide (at STP) b. 1.68 g of magnesium ions c. 69.6 g of sodium hypochlorite d. 4.27 x 10²⁴ molecules of carbon monoxide
a. 2.41 mol b. 6.91 x 10⁻² mol c. 09.34 mol d. 7.09 mol
Complete each equation and then write a net ionic equation. a. A1(s) + H₂SO₄(aq) → b. HC1(aq) + Ba(OH)₂(aq) → c. Au(s) + HC1(aq) →
a. 2A1(s) + 6H⁺(aq) → 2A1³(aq) + 3H²(g) b. H⁺(aq) + OH⁻(aq) → H₂O(l) c. no reaction
Write balanced chemical equations for these decomposition reactions. a. Aluminum is obtained from aluminum oxide with the addition of a large amount of electrical energy. b. Heating tin (IV) hydroxide gives tin (IV) oxide and water. c. Silver carbonate decomposes into silver oxide and carbon dioxide when it is heated.
a. 2AI₂O₃ →∆→ 4A1 + 3O₂ b. Sn(OH)₄ →∆→ SnO₂ +2H₂O c. Ag₂CO₃ →∆→ Ag₂O + CO₂
Balance each equation. a. AgNO↓3 + H↓2S -----> Ag↓S + HNO↓3 b. Zn(OH)↓2 + H↓3PO↓4 -----> Zn↓3(PO↓4)↓2 + H↓2O
a. 2AgNO↓3 +H↓2S -----> Ag↓2S + 2HNO↓3 b. 3Zn (OH)↓ + 2H↓3PO↓4 -----> Zn↓3 (PO↓4)↓2 + 6H↓2O
Write a balanced chemical equation for each decomposition reaction. a. Ag₂O(s) ↔∆↔ ? b. ammonium nitrate ↔∆↔ dinitrogen monoxide + water
a. 2Ag₂O →∆→ 4Ag + O₂ b. NH₄NO₃ →∆→ N₂O + 2H₂O
Write a balanced equation for the complete combustion of each compound. a. formic acid (HCOOH) b. heptane (C₇H↓₁₆)
a. 2HCOOH + O₂ -----> 2CO₂ + 2H₂O b. C₇H₁6 + 11O₂ -----> 7CO₂ + 8H₂O
Write balanced chemical equations for the following combination reactions. a. Mg + O₂ → b. P + O₂ → diphosphorus pentoxide c. Ca + S →
a. 2Mg + O₂ → 2MgO b. 4P + 5O₂ → 2P₂O₅ c. Ca + S → CaS
Balance the following equations. a. PbO₂ → PbO + O₂ b. Fe(OH)₃ → Fe₂O₃ +H₂O c. (NH₄)₂CO₃ → NH₃ + H₂O + CO₂ d. NaC1 + H₂SO₄ → Na₂SO₄ + HC1
a. 2PbO₂ → 2 PbO + O₂ b. 2Fe(OH)₃ → Fe₂O₃ + 3H₂O c. (NH₄)₂CO₃ → 2NH₃ + H₂O + CO₂ d. 2NaC1 + H₂SO₄ + 2HC1
Write a balanced equation for each reaction. a. KOH(aq) + H₃PO₄(aq) -----> b. H₂SO₄(aq) + AI(OH)₃(aq) ----->
a. 3KOH(aq) + H₃PO₄(aq) + 3H₂O(l) b. 3H₂SO₄(aq) + 2AI(SO₄)₃(aq) + 6H₂O(l)
Write the products of these double-replacement reactions. Then balance each equation. a. NaOH(aq) + Fe(NO₃)₃(aq) -----> (Iron (III) hydroxide is a precipitate.) b. Ba(NO₃)₂(aq) + H₃PO₄(aq) -----> (Barium phosphate is a precipitate.)
a. 3NaOH(aq) + Fe(NO₃)₃(aq) -----> Fe(OH)₃(s) + 3NaNO₃(aq) b. 3Ba(NO₃)₂(aq) + 2H₃PO₄(aq) -----> Ba₃(PO₄)₂(s) + 6HNO₃(aq)
Balance equations for each item. The formula for each product (object) is given. a. a basketball team center + forward + guard → team C + F + G → CF₂G₂ b. a tricycle frame + wheel + seat + pedal → tricycle F+W+S+P → FW₃SP₂
a. C + 2F + 2G → CF₂G₂ b. F + 3W + S = 2P → FW₃SP₂
Write a balanced chemical equation for each reaction. Use the necessary symbols from Table 11.1 to describe the reaction completely. a. Bubbling chlorine gas through a solution of potassium iodide gives elemental iodine and a solution of potassium chloride. b. Bubbles of hydrogen gas and aqueous iron (III) chloride are produced when metallic iron is dropped into hydrochloric acid. c. Solid tetraphosphorus decoxide reacts with water to produce phosphoric acid.
a. C1₂(g) + 2K1(aq) → I₂(aq) + 2KC1(aq) b. 2Fe(s) + 6HC1(aq) → 2FeC1₃(aq) + 3H₂(g) c. P₄O₁₀(s) + 6H₂O(l) → 4H₃PO₄(aq)
Acqueous solutions of sodium sulfide and cadmium nitrate were mixed in a bleaker. a. Write the formula of the yellow precipitate. b. Identify the spectator ions in the solution. c. Write the net ionic equation for the reaction.
a. CdS(s) b. Na⁺(aq) and NO₃⁻(aq) c. Cd²(aq) +S²⁻(aq) → CdS(s)
Write a balanced equation for the complete combustion of each compound. a. butene (C₄H₈) b. acetone (C₃H₆O)
a. C₄H₈ + 6O₂ → 4CO₂ + 4H₂O b. C₃H₆O + 4O₂ → 3CO₂ + 3H₂O
Alkanes are hydrocarbon molecules that have the general formula CₙH₂ₙ₊₂. The graph shows the number of oxygen, carbon dioxide, and water molecules needed to balance the equations for the complete combustion of every alkane having from one to ten carbon atoms. CₙH₂ₙ₊₂ + ____ O₂ → ____CO₂ + ____ H₂O See graph on page 349 - Question #69 (It won't allow me to pics on term side. Only definition side). a. Use the graph to write balanced equations for the combustion of C₅H₁₂ and C₉H₂₀. b. Extrapolate the graph and write balanced equations for the combustion of C₁₂H₂₆ and C₁₇H₃₆. c. The coefficient for O₂ in the general equation is as follows. n + (n+1/2). What are the coefficients for CO₂ and H₂O?
a. C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O; C₉H₂₀ + 14O₂ → 9CO₂ + 10H₂O b. 2C₁₂H₂₆ + 37O₂ → 24CO₂ + 26H₂O; C₁₇H₃₆ + 26O₂ → 17CO₂ → 18H₂O c. n=CO₂; (n+1) = H₂O
Complete the equations for these single-replacement reactions in aqueous solution. Balance each equation. Write "no reaction" if a reaction does not occur. Use the activity series. a. Fe(s) + Pb(NO↓3)↓2(aq) -----> b. Cl↓2(aq) + NaI(aq) -----> c. Ca(s) + H↓2O(l) ----->
a. Fe(s) + Pb(NO↓3)↓2(aq) -----> Fe(NO↓3)↓2(aq) + Pb(s) b. Cl↓2(aq) + ↓2NaI(aq) -----> 2NaCl(aq) + I↓2(aq) c. Ca(s) + 2H↓2O(l) -----> Ca(OH)↓2(aq) + H↓2(g)
Write sentences that completely describe each of the chemical reactions shown in these skeleton equations. a. NH₃(g) + O₂(g) ↔PT↔ NO (g) + H₂O(g) b. H₂SO₄ (aq) + BaCl₂(aq) → BaSO₄(s) + HC1(aq) c. N₂O₃(g) + H₂O(l) → HNO₂(aq)
a. Gaseous ammonia and oxygen react in the presence of a platinum catalyst to produce nitrogen monoxide gas and water vapor. b. Aqeous solutions of sulfuric acid and barium chloride are mixed to produce a precipatate of barium sulfate and aqueous hyrochloric acid. c. The gas dinitrogen trioxide reacts with water to produce an aqueous solutions of nitrous acid.
Write a balanced equation for each of the following double-displacement reactions. a. H₂C₂O₄(aq) + KOH(aq) → b. CdBr₂(aq) + Na₂S(aq) → (Cadmium sulfide is a precipitate.)
a. H₂C₂O₄(aq) + 2KOH(aq) → K₂C₂O₄(aq) + 2H₂O(l) b. CdBr₂(aq) + Na₂S(aq) → CdS(s) + 2NaBr(aq)
Rewrite these word equations as balanced chemical equations. a. hydrogen + sulfur -----> hydrogen sulfide b. iron (III) chloride + calcium hydroxide -----> iron (III) hydroxide + calcium chloride
a. H↓2 + S -----> H↓2S b. 2FeCl↓3 + 3Ca(OH)↓2 -----> 2Fe(OH)↓3 + 3CaCl↓2
Fill in the missing reactant and then balance each equation. a. K(s) + ____ → KOH(aq) +H₂(g) b. C₂H₅OH(l) + ____ → CO₂(g) + H₂O(g) c. Bi(NO₃)₃(aq) + ____ → Bi₂S₃(s) + HNO₃(aq) d. A1(s) + ____ → A1Br₃(s) e.HNO₃(aq) + ____ → Ba(NO₃)₂(aq) + H₂O(l)
a. K(s) + 2H₂O(l) → KOH(aq) + H₂(g) b. C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(g) c. 2Bi(NO₃)₃(aq) + 3H₂S(g) → Bi₂S₃(s) + 6HNO₃(aq) d. 2A1(s) + 3Br₂(l) → 2A1Br₃(s) e. 2HNO₃(aq) + Ba(OH)₂(aq) → Ba(NO₃)₂(aq) + 2H₂O(l)
Write a balanced chemical equation for each combination reaction. a. Sodium oxide + water → b. Hydrogen + bromine → c. Dichlorine heptoxide + water →
a. Na₂O(s) + H₂O(l) → 2NaOH(aq) b. H₂(g) + Br₂(g) → 2HBr(g) c. C1₂O₇(l) + H₂O(l) → HC1O₄(aq)
Are any of the following formula units for ionic compounds incorrect? If so, write the correct formulas. a. K₂Br b. Na₂S c. CaN₂ d. A1₂O₃
a. incorrect; KBr b. correct c. incorrect; Ca₃N₂ d. correct
Pieces of sodium and magnesium are dropped into separate water-filled test tubes (A and B). This is vigorous bubbling in Tube A, but no in Tube B. a. Which tube contains the sodium metal? b. Write an equation for the reaction in the tube containing the sodium metal. What type of reaction is occurring in this tube?
a. tube A b. 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g); single-replacement
When you take a glass of cold liquid outside on a warm, humid day, drops of liquid soon form on the outside of the glass. a. What is the liquid? b. Where did the liquid come from? c. Did a chemical or physical change occur?
a. water b. water vapor in the air c. physical change.
What is a balanced equation?
an equation in which each side of the equation has the same number of atoms of each element and mass is conserved.
How do you write a word equation?
write the names of the reactants to the left of the arrow separated by plus signs; write the names of the products to the right of the arrow, also separated by plus signs.