Chemical Reactions
Dec 24, 2015
Chemical Reactions Study Guide• Chpt. 9.4 Acids and Bases
• Chpt. 11: Balancing, Classifying, and Predicting Chemical Reactions
• Chapter 17.1: Thermochemistry (pg. 505-506)
• Chpt. 18.1: Reaction Rates
Chemistry (2/25)
• Acid/Base Quiz• Interpreting and Balancing chemical equations
Due: • Acid/Base Nomenclature worksheet for partial
credit
Chemical Reactions Objectives1.Classify and name compounds in chemical reactions2.Describe chemical reactions in word and chemical
equations.3.Balance chemical equations based on the Law of
Conservation of Mass.4.Identify and classify types of chemical reactions
and energy changes involved.5.Predict products and energy changes in a chemical
reaction. 6.Identify and test factors that affect the rate of
chemical reactions.
Chemistry (2/26)Infinite Campus Update: • Acid/Base Nomenclature Worksheet (10pts.)• Acid/Base Quiz (15pts.)*Check infinite a lot of missing assignments!*
Objectives:• Interpreting and Balancing chemical equations
Homework: • Check for missing assignments on infinite campus• Balancing chemical equations worksheet
Chemical Reaction Pre-Test1. What is a chemical reaction?2. If matter is conserved during a chemical reaction, how is
it new matter is “created”?3. Complete the questions below on the following word
equation: Fe(s) + O2 (g) ----> FeO (s) a. Give an example of a reactant from this reaction.b. Give an example of a product from this reaction. c. Balance the chemical equation if needed. d. Circle the type of chemical reaction you think this
represents. synthesis decomposition replacement neutralization combustion
Chemical Reactions• Substances chemically interact to form different
substances. • A substance can be an element or a compound.
• Chemical bonds are broken and created.
Example: Fe(s) + O2 (g) ----> FeO (s)
Chemical Equations Fe + O2 ------> FeO
Reactants:
• Starting substances.• Chemically interact with one another.• Usually located to the left of the arrow.Products:• Ending substances.• Substances formed from the chemical reaction.• Usually located to the right of the arrow.
Chemical Equations Fe(s) + O2 (g) ------> FeO (s)
Abbreviations for state of matter in an equation.• (s)= substance in solid state• (g)= substance in gaseous state• (l)= substance in liquid state• (aq)= substance dissovled in water. (aqueous solution)
Law of Conservation of Mass Fe(s) + O2 (g) ------> FeO (s)
• Are atoms destroyed or created during a chemical reaction?
• No, they are just rearranged to produce new substances.
Law of Conservation Of Mass
• Matter is not created or destroyed.
• Matter is just rearranged.(mass of reactants = mass of products)
That is why it is important to balance chemical equations.
Balancing Chemical EquationsWhy? Observe the Law of Conservation of Mass
Rules: 1. Add coefficients in front of substances, do NOT
change subscripts.
2. First balance elements that only appear once on each side of the equation.
3. Make sure coefficients are expressed in lowest terms.
Chemistry (2/27)Objectives:• Interpreting and Balancing chemical equations• Review acid/base quiz
Homework: • Balancing equations worksheet(due Thursday)• Law of Conservation of Mass pre-lab qts. and hypothesis• Review acids/bases nomenclature• Check for missing assignments in infinite campus
Lab: Law of Conservation of Mass Lab: (Thursday)
Law of Conservation of Mass LabHomework: • Read through the background and procedures
section.• Complete pre-lab questions and hypothesis.
Balancing Chemical Equations a. K + MgCl2 ---------> KCl + Mg
b. Ag2O ---------> Ag + O2
c. CH4 + O2 -------> CO2 + H2O
Chemistry (2/28)Objectives:• Interpreting and Balancing Chemical Equations• Validate the Law of Conservation of Mass with scientific
evidence.
Due Today: • Balancing chemical equations worksheet (turn in tray)• Law of Conservation of Mass pre-lab qts. and hypothesis
Homework: • Balancing Chemical Equations practice problems (Fri.)• Check for missing assignments in infinite campus
Balancing Chemical Equations
Dihydrogen monoxide + sodium (bicarbonate) ---> carbon dioxide + sodium hydroxide + dihydrogen monoxide
Law of Conservation of Mass LabPurpose: Validate the Law of Conservation of Mass
Lab Reminders: • Follow ALL lab procedures carefully.• Use the same balance for all measurements.
Chemistry (3/4)Infinite Campus Update:• Conservation of Mass Lab (12pts.)• Balancing Chemical Equations (10pts)Objectives: • Balancing Chemical Equation Quiz• Classifying Chemical Reactions• Discuss Law of Conservation of Mass LabHomework: (Due Wed.)• Balancing Chemical Equations Worksheet• Classifying Chemical Reactions Worksheets
Chemical Reactions Objectives1. Identify and classify types of chemical reactions.
2. Identify energy changes involved with chemical reactions.
3. Predict products and energy changes in a chemical reaction.
Chemistry (3/6)Infinite Campus Update:• Balancing Chemical Equations Quiz (14pts.) Due Today:• Balancing Chemical Equation Worksheet (10pts.)Objectives: • Classifying Chemical Reactions• Identify energy changes associated with chemical
reactions• Discuss Balancing Chemical Equation QuizHomework: (Due Wed.)• Classifying Chemical Reactions Worksheets • Chemical Reaction Lab (pre-lab qts.)
Chemistry (3/6)Infinite Campus Update:• Balancing Chemical Equations Quiz (14pts.) Objectives: • Address qts. over Balancing Chemical Equation Quiz• Address qts. over Balancing and Classifying wks
(homework) • Discuss Neutralization Reaction • Introduce Chemical Reaction LabHomework: (Due Wed.)• Chemical Reaction Lab (pre-lab qts.)
Chemical Reaction Lab
Purpose: To perform and observe eight chemical reactions in the lab.
Homework: Read the introduction, background, and
procedures section; then answer the pre-lab questions on the front. (1-9)
Types of Chemical Reactions
1. Synthesis (R+ S ----> RS)2. Decomposition (RS------> R+ S)3. Single Replacement (T+ RS ---> TS + R)4. Double Replacement (R+S- + T+U- ---> R+U-+ T+S-)5. Combustion (CxHx + O2 ----> CO2 + H2O)
6. Neutralization (Acid + Base--> H2O + Salt)
(type of double replacement reaction)
Synthesis (Combination) Reaction
• 2 or more substances chemically combine to form a single substance.
• R+ S ----> RS + energy
• More energy is released at the end of the reaction then is needed to start the reaction.
(energy released by surroundings > energy absorbed by system)
Decomposition Reaction
• A compound breaks down into simpler substances.
• RS + energy ----> R + S
• More energy is required to start the reaction then is released at the end of the reaction.
(energy absorbed by system > energy released to surroundings)
.
Single Replacement Reaction
• An element replaces another element in a compound.
• T+ RS ---> TS + R + energy
• Usually energy of surrounding > energy of system
Double Replacement Reaction
• Exchange of cations between two ionic compounds. • R+S- + T+U- ---> R+U-+ T+S- + energy
• Usually energy of surrounding > energy of system
Combustion Reaction
• Fuel (CHO) reacts with oxygen to produce predictable substances and energy.
• CxHx(Ox) + O2 ----> CO2 + H2O + ENERGY
• Always energy of surroundings > energy of system
Neutralization • An acid and a base react to produce predictable
products. • Changes the pH to 7 (neutral).
Acid + Base -------> H2O + Salt(ionic compounds)
Salt: The cation comes from the base and the anion from the acid.
Ex. Na(OH) + HCl NaCl + H2O
Chemistry (3/11)Due: • Classifying and Balancing Chemical Equations wksht• Pre-lab questions(1-9) from Chemical Reaction Lab
Objectives:• Chemical Reaction Lab
Homework: • Turn in 3rd qtr. missing assignments for partial
credit.(Deadline: Wed. 3/13)
Chemical Equations to LabWrite the reactants for each reaction, and then predict
what type of reaction you think you are going to observe.
1. Mg + O2 ------>
2. Mg + HCl ----> 3. (NH4)2(CO3) ----->
4. Ca(CO3) + HCl ---->
5. Zn + CuCl2 ---->
6. CuCl2 + Na3(PO4) --->
7. HCl + Na(OH) ----> 8. C2H6O + O2 ----->
Chemical Reaction Lab (3/11)
Purpose: • Predict the type of reaction for each experiment. • Perform, observe, and record data for each
chemical reaction.
Chemistry (3/12)Infinite Campus Update:• Classifying and Balancing Chemical Rxtns. (10pts.)
Objective: • Chemical Reaction Lab
Homework:• Balancing reactions and establishing a conclusion
for the lab.
Chemical Reaction Lab (3/12)
Purpose: • Complete chemical reaction lab.• Predict products of each reaction.• Balance each chemical reaction.
Chemistry (3/13)Objectives• Predict products of each reaction from the lab• Balance equations(if needed) and establish
conclusion for lab.
Homework:• Complete chemical reaction lab
Chemical Equations to LabPredict the products of each reactant.1. Mg + O2 ------> MgO
2. Mg + HCl ----> 3. (NH4)2(CO3) -----> NH3 + CO2 + H2O
4. Ca(CO3) + HCl ----> CaCl2 + H2O + CO2
5. Zn + CuCl2 ---->
6. CuCl2 + Na3(PO4) --->
7. HCl + Na(OH) ----> 8. C2H6O + O2 ----->
Chemical Equations to Lab
Just need to check and see if they are balanced. 1. Mg + O2 ------> MgO
2. Mg + HCl ----> MgCl + H2
3. (NH4)2(CO3) -----> NH3 + CO2 + H2O
4. Ca(CO3) + HCl ----> CaCl2 + H2O + CO2
5. Zn + CuCl2 ----> ZnCl2 + Cu
6. CuCl2 + Na3(PO4) ---> Cu3(PO4)2 + NaCl
7. HCl + Na(OH) ----> H2O + NaCl
8. C2H6O + O2 -----> CO2 + H2O
ConclusionA summary that includes the following: • Identify and explain which reactions from the lab
were synthesis, decomposition, single replacement, double replacement, neutralization, combustion.
• Based on the data section explain which reactions were exothermic and endothermic.
• Which reaction(s) did you like the best and why?
• What did you learn from this lab? (be specific)
Chemistry (3/14)Due Today:• Chemical Reaction Lab
Objectives: • Classifying reactions• Predicting products• Balancing chemical equations
Homework: • Predicting products and balancing equations wks.
(Chemistry 3/15)Infinite Campus:*Chemical Reaction Lab (26pts. )-3rd qtr.*
Objectives:• Classify reactions• Predict products• Balance Chemical Equations
Homework:• Complete Predicting Products Worksheet.• Complete internet enrichment problems.
Monday: Quiz over chemical reactions. Study!
Chemical ReactionsPredict the products for each reaction and balance if needed.
a. 3Ca + N2 --------> Ca3N2 (synthesis)
b. Cu2S -------> 2Cu + S (decomposition)
c. 2NaBr + F2 ------> 2NaF + Br2 (single replace)
d. CH4 + 2O2 -----> CO2 + 2H2O (combustion)
e. H2(CO3) + 2K(OH) -----> K2(CO3) + 2H2O (neutralization)
Chemistry (3/18)Objectives:• Classifying, Balancing, Predicting Products• Activity Series Table and Single Replacement
Homework:• Activity Series Pre-Lab reading and hypothesis• Chemical Reaction Quiz (Wednesday)• Work on study guide (Test Monday)
Chemical Reactions: Bell Ringer1. What are the coefficients that will balance the
chemical equation below? AlCl3 + Na(OH) ----> Al(OH)3 + NaCl
a. 1,3,1,3b. 3,1,3,1c. 1,1,1,3d. 1,3,3,12. What type of chemical reaction is expressed above?
3. Predict the product(s) and balance if needed: Ba (s) + O2 (g) ---------->
Predicting Products Gallery Walk
Objective: • Classify Type of Reaction• Predict Products• Balance Equation
Gallery Walk: Predicting Products
At each station complete the following: a. Predict the type of reactionb. Predict the productsc. Balance the chemical equation if needed
Chemistry (3/19)Objectives:• Activity Series Table and Single Replacement
Homework:• Activity Series Lab conclusion and post-Lab
questions• Chemical Reaction Quiz (Wednesday)• Work on study guide (Test Monday)
Activity Series Lab Hypothesis CuCl2(aq) Ag(NO3) HCl (aq) dH(OH) (l)
Copper (s)
Magnesium (s)
Zinc (s)
Calcium (s)
Chemistry (3/20)Objectives:• Chemical Reaction Quiz• Discuss Activity Series Lab• Discuss Endothermic and Exothermic Energy
Diagrams
Homework:• Complete Activity Series Lab• Energy Changes Worksheet• Work on Study Guide
Activity Series Lab
*After complete quiz, work on the following: Activity Series Lab:• Complete conclusion and post-lab questions.
Chemistry (3/21)Infinite Campus Update:• Chemical Reaction Quiz (16pts.)Due: Activity Series Lab
Objectives: • Interpreting Activity Series Table• Interpret energy changes in chemical reactions.• Identify and test factors that affect the rate of chemical
reactions.
Homework: Work on study guide.
Activity Series Table
*Study Guide Modification: omit qts. 18
Bell Ringer: Work on qts. 13 from study guide.
Thermochemistry • Study of energy changes during a reaction.
Energy Review Qts:• When observing a chemical reaction what is the
difference between the system and its surroundings?
• Energy always flows from ____ matter to _____ matter. (cold, hot)
Chemistry:3/22Infinite Campus:Chemical Reaction Quiz (16pts) Assignments Collected:Activity Series LabObjectives: • Interpret and classify energy changes in
reactions• Identify and predict how factors affect the
speed of a reaction.
Thermochemistry Energy changes that occur within reactions.
Endothermic Reactions Exothermic Reactions
Exothermic Reaction• Energy (H) absorbed < Energy (H) released. • The chemical reaction becomes cooler and its surroundings gets
warmer. • Test tube gets? • Energy is on the products side.• Examples: • combustion of fossil fuels (transportation)C8H18 + O2 -------> CO2 + H2O + energy
• cellular respiration in living organisms C6H12O6 + O2 ------> CO2 + H2O + energy
Endothermic Reactions• Energy (H) absorbed > Energy (H) released• Chemical reaction gets warmer and its
surroundings gets cooler. • Test tube gets ?• Energy is on the reactants side.Ex. Photosynthesis
Chemical Reaction Energy Diagram•Activation Energy (Ea): The minimum amount of energy needed for the reaction to occur.
H: Energy change between reactants and products. ( H = H products – H reactants)
Energy Diagram H reactant > H product Small activiation energy More energy will be released in this reaction
(H)
(time)
Energy Diagram
Activation Energy
Does this represent an endothermic or exothermic reaction?
(H)
(time)
Endothermic Energy Diagram
Activation Energy
• H reactant < H product•Large activation energy•More energy will be absorbed in this reaction
Thermochemistry Examples Classify the following examples as endothermic
(E) or (Ex) exothermic:1. If the surroundings gets cooler and the
system gets warmer.2. Ice cream melting. 3. Melted paraffin wax is left at room
temperature until it solidifies.4. AlCl3 ------> Al + Cl2 + energy5. A bright light is created when magnesium
reacts with oxygen.6. When hydrochloric acid reacts with
magnesium the test tube will get warm.
Chemical Reactions Rates• Reaction Rates = how fast the reactants
chemically change into the products. • Collision Theory: Reactant particles will form
products when reactants collide:- at the right position.- and exchange the right amount of kinetic energy.
Rates of Chemical Reactions
• What are factors that can affect the rates of reactions?
• Temperature• Concentration of Reactants• Surface Area of Reactants• Catalysts• Inhibitors
Temperature of Reaction
What if we increase the temperature of a reaction?
What if we decrease the temperature of a reaction?
Catalysts
• Catalysts speed up reactions, but they are not apart of the chemical reaction.
Ex. Enzymes keep your body temperature around 37oC (98 oF) by speeding up important biological reactions.
Inhibitors
• Inhibitors slow down a chemical reaction, but are not apart of the reaction.
• Inhibitors bind to a catalyst and prevent it from speeding up a reaction.
Ex. Preservation of food. Antioxidants prevent foods from becoming stale or moldy.
Chemical Reactions Study Guide
• Chpt. 9.4 Acids and Bases
• Chpt. 11: Balancing, Classifying, and Predicting Chemical Reactions
• Chpt. 18.1: Reaction Rates