Presentation on theme: "Chapter 8.1. Warm up 1. What is a chemical reaction? 2. What is conservation of mass? 3. How are the two concepts above related? 4. When heated, solid."— Presentation transcript:
Warm up 1. What is a chemical reaction? 2. What is conservation of mass? 3. How are the two concepts above related? 4. When heated, solid potassium chlorate decomposes to form solid potassium chloride and oxygen gas. Write the balanced equation. (chlorate = ClO 3 -1 ) Make sure your warms ups are ready to turn in: dates clear and boxes or highlighted, name on paper 2KClO 3 (s) → 2KCl(s) + 3O 2 (g)
Writing Chemical Equations Chemical reactions occur every day. Digesting photosynthesiscooking In a chemical reaction, one or more reactants are converted to one or more new products.
Evidence of chemical reactions How do you know if a chemical reaction has occurred? Change in energy (gets hot or cold) Produce a gas (bubbles) Color change Form a precipitate= form solid from 2 liquids
Symbols to know Yield (produces) Reaction in both directions (s) Solid form (l) Liquid (aq) Aqueous= Dissolved in water (g) gas H 2 SO 4 (aq) H 2 (g) + S (s) + O 2 (g) Subscript # = number of atoms of each element
Represent Reactions with chemical equations Word equations Ex: Iron reacts with oxygen gas to produce iron (III) oxide. Iron + oxygen gas iron (III) oxide How many reactants and products in the following? 1. Hydrogen peroxide decomposes to produce water and oxygen gas Hydrogen peroxide water + oxygen 2. Methane and oxygen gas react to produce carbon dioxide and water Methane + oxygen carbon dioxide + water
Chemical Equation Chemical equations replace words with formulas. Skeleton chemical equations do NOT show the relative abundance of each chemical. THEY ARE UNBALANCED. Ex: Oxygen and hydrogen combine to form water O 2 (g) + H 2 (g) H 2 O (l)
Write the skeleton chemical equations 1. Solid Iron reacts with oxygen gas to produce iron (III) oxide (rust). 2. Aqueous Hydrogen peroxide (H 2 O 2 ) decomposes to produce water and oxygen gas. 3. Solid sulfur burns in the presence of oxygen gas to form sulfur dioxide gas. Fe(s) + O 2 (g) → Fe 2 O 3 (s) H 2 O 2 (aq) → H 2 O (l) + O 2 (g) S(s) + O 2 (g) → SO 2 (g)
Balancing Chemical Equations Subscripts—used in formulas Coefficients—before the symbol, used to balance equations Solid sulfur burns in the presence of oxygen to form sulfur dioxide gas. Iron reacts with oxygen gas to produce iron (III) oxide. YOU CANNOT CHANGE SUBSCRIPTS TO BALANCE!!! S (s) + O 2 (g) SO 2 (g) Fe(s) + O 2 (g) → Fe 2 O 3 (s) 4Fe(s) + 3O 2 (g) → 2Fe 2 O 3 (s) H 2 (g) + O 2 (g) H 2 O (l)
Write the Coefficient to Balance - balance the more complicated molecule first, then single molecules 1. ___H 2 (g) + ___O 2 (g) ___H 2 O (l) 2. ___Ag 2 S (s) + ___Al(s) ___Ag(s) + ___Al 2 S 3 (s) 3. ____AgNO 3 + ____H 2 S ___Ag 2 S + ____HNO 3 1. When heated, solid potassium chlorate decomposes to form solid potassium chloride and oxygen gas. 2KClO 3 (s) → 2KCl(s) + 3O 2 (g) 2
Why Balance?? Law of conservation of mass says so… Law of Conservation of Mass: - Total mass of the universe is constant - Mass can not be created or destroyed - In a closed system, mass can not change quantity (though it can change form)
Balancing Equations - put in classwork section of notebook 1. __Li(s) + __Cl 2 (g) → __LiCl(s) 2. __Fe(s) + __O 2 (g) → __Fe 2 O 3 (s) 3. __H 2 O 2 → __H 2 O + O 2 4. __KClO 3 (s) → __KCl(s) + __O2(g) 5. __P 4 (s) + __Cl 2 (g) → __PCl 3 (l) Write the balanced equation by filling in the coefficients. If the coefficient is 1, you don’t write anything
6.Aluminum metal reacts with oxygen gas to produce aluminum oxide solid. 7.Gaseous nitrogen dioxide decomposes to form dinitrogen tetroxide gas. 8.Solid diboron trioxide reacts with water to form boric acid (H 3 BO 3 ) in aqueous solution. Advanced problems: 9. __NH 3 + __O 2 __NO + __H 2 O 10. __C 2 H 6 + __O 2 __H 2 O + __CO Balancing Equations - put in classwork section of notebook
Bozeman chemical bonding https://www.youtube.com/watch?v=_B735turD oM
Answers 1. 2Li(s) + Cl 2 (g) → 2LiCl(s) 2. 4Fe(s) + 3O 2 (g) → 2Fe 2 O 3 (s) 3. 2H 2 O 2 → 2H 2 O + O 2 4. 2KClO 3 (s) → 2KCl(s) + 3O2(g) 5. P 4 (s) + 6Cl 2 (g) → 4PCl 3 (l) 6. Aluminum metal reacts with oxygen gas to produce aluminum oxide solid. 4Al(s) + 3O 2 (g) → 2Al 2 O 3 (s) 7. Gaseous nitrogen dioxide decomposes to form dinitrogen tetroxide gas. 2NO 2 (g) → N 2 O 4 (g) 8. Solid diboron trioxide reacts with water to form boric acid (H 3 BO 3 ) in aqueous solution. B 2 O 3 (s) + 3H 2 O(l) → 2H 3 BO 3 (aq) 9. 4NH 3 + 5O 2 4NO + 6H 2 O 10. 2C 2 H 6 + 5O 2 6H 2 O + 4CO
3.Aqueous Hydrogen peroxide decomposes to produce water and oxygen gas. 4.Solid sulfur burns in the presence of oxygen to form sulfur dioxide gas. 5.Write the balanced synthesis reaction showing the production of Magnesium nitride from its elements. 6.Solid Iron (III) sulfide is produced from its solid elements. Write the balanced equation for this reaction.
We will change seats, but not today. Start a new warm up paper: 1/6/15 Name Per, Row Warm-ups #1 1. 2. Saving paper is always good! _/__/15 1. What did you do well in Chemistry class last semester? 2. What was something that was hard for you? 3. Set one goal for yourself for this semester in chemistry class. Read the article “peeing in the pool…” 4. How does your chemistry knowledge help you understand this article? 5. What elements do you think make up cyanogen chloride? Thrichloramine?
Warm up 1. What did you do well in Chemistry class last semester? 2. What was something that was hard for you? 3. Set one goal for yourself for this semester in chemistry class.
Reminders/ thing to do Grades from last semester are final, you are starting with a clean slate! Need a notebook, red pen, and calculator Can continue using the same notebook, if you have enough room (this is recommended) Clean out your binder/ backpack! (store stuff at home if you want) Keep your final study guide! Use it to reference material you might forget!
After correcting test: Title a paper: “Ch 8.1 bookwork” Read ch 8.1 pg 260-275 Answer: Pg. 274 “practice” 1. a-c and Section Review # 1-2, 4-5 And pg 275 #1-2
Warm upLab Safety Review 1. What is the most important rule in the lab? 2. When using a Bunsen burner, what important safety precautions do you need to take? (min of 3) 3. What can you do to avoid skin contact with any chemicals? 4. If you do accidently get a chemical on you, what should you do?
Semester 2 Ch 8: Chemical Reactions ClIF H BrON Diatomic Elements: mnemonic devise Cl 2, I 2, F 2, H 2, Br 2, O 2, N 2
5 Types of Chemical Reactions 1. Synthesis 2. Decomposition 3. Single Replacement 4. Double Replacement 5. Combustion
1. Synthesis 2 or more substances combine into one single product Examples: Mg (s) + O 2 (g) MgO (s) K + Cl 2 KCl Cu + S CuS Ex: Write the balanced synthesis reaction showing the production of Magnesium nitride from its elements. Ex: Solid Iron (III) sulfide is produced from its solid elements. Write the balanced equation for this reaction
2. Decomposition The break down of a single substance into 2 or more products Examples HgO (s) Hg (l) + O 2 (g) H 2 SO 4 (aq) H 2 (g) + S (s) + O 2 (g) HI H 2 + I 2 Ex: Write the formula showing the decomposition of hydrobromic acid (HBr) into the diatomics hydrogen gas and bromine liquid Ex: When electricity is applied water as a catalyst, it forces the decomposition of it into diatomic gases of hydrogen and oxygen. Write the balanced equation for this reaction https://www.youtube.com/watch?v=mamoT11TEV4
3. Single Replacement One element replaces a 2 nd in a compound. Metals displace metals, non-metals displace non-metals Hydrogen is the exception (acts like a metal) Examples Zn + Cu(NO 3 ) 2 Cu + Zn(NO 3 ) 2 Br 2 + NaI I 2 + NaBr Zn + H 2 SO 4 H 2 + ZnSO 4
Would the following reaction occur?? CaCl 2 + Na NaCl + Ca Will Na displace Ca??? Why? Why not? Activity Series: show how reactive an element is. Pg 286 -a more reactive element will replace a less reactive element
Will it react? If so, what is the product? 1. Zn + H 2 O (l) 2. Sn + O 2 3. Cd + Pb(NO 3 ) 2 4. Cu + HCl 5. Will solid iron and Lead (II) nitrate react in a single replacement reaction? If so, write the balanced chemical formula for this reaction. Cd(NO 3 ) 2 + Pb SnO or SnO 2 No reaction
4. Double Replacement 2 elements (metals/+ ions) switch partners. Examples Na 2 S + Cd(NO 3 ) 2 CdS + NaNO 3 NaCN + H 2 SO 4 Ca(OH) 2 + HCl HOH + CaCl 2 HOH = Water + + https://www.youtube.com/watch?v=opY3FLrPTa4 HCN + Na 2 SO 4
Synthesis Decomposition Single replacement Double replacement
Write and Balance 1. In a double replacement reaction sodium hydroxide (NaOH) and iron (III) nitrate react. Write the balanced formula for this reaction. 2. Aqueous barium nitrate and aqueous phosphoric acid (H 3 PO 4 ) react to produce barium phosphate precipitate and aqueous nitric acid (HNO 3 ).
5. Combustion Reaction When a compound or element is burned (in the presence of oxygen) Energy in the form of heat and light is produced Hydrocarbons are often the other reactant. Complete combustion products are always CO2 and H2O Incomplete combustion products are typically C (soot), CO gas and H2O https://www.youtube.com/watch?v=UygUcMkRy_c
Examples of Combustion Rxns C 6 H 6 + O 2 CO 2 + H 2 O (benzene) CH 4 + O 2 CO 2 + H 2 O (methane) Ex: Write a balanced equation for the complete combustion of glucose (C 6 H 12 O 6 ).
1. 2SO 2 + O 2 2SO 3 2. Al 2 (SO 4 ) 3 + 3Ca(OH) 2 2Al(OH) 3 + 3CaSO 4 3. 2C 2 H 2 + 5O 2 4CO 2 + 2H 2 O 4. Mg + 2AgNO 3 Mg(NO 3 ) 2 + 2Ag 5. 3Ba(NO 3 ) 2 + 2H 3 PO 4 Ba 3 (PO 4 ) 2 + 6HNO 3 6. Mg(ClO 3 ) 2 MgCl 2 + 3O 2 7. 2Be + O 2 2BeO 8. 2Al + 3CuSO 4 Al 2 (SO 4 ) 3 + 3Cu 9. 2PbO 2 2PbO + O 2 10. 2C 2 H 6 + 7O 2 4CO 2 + 6H 2 O What type of chemical reaction is each of the following?
1. 2SO 2 + O 2 2SO 3 2. Al 2 (SO 4 ) 3 + 3Ca(OH) 2 2Al(OH) 3 + 3CaSO 4 3. 2C 2 H 2 + 5O 2 4CO 2 + 2H 2 O 4. Mg + 2AgNO 3 Mg(NO 3 ) 2 + 2Ag 5. 3Ba(NO 3 ) 2 + 2H 3 PO 4 Ba 3 (PO 4 ) 2 + 6HNO 3 6. Mg(ClO 3 ) 2 MgCl 2 + 3O 2 7. 2Be + O 2 2BeO 8. 2Al + 3CuSO 4 Al 2 (SO 4 ) 3 + 3Cu 9. 2PbO 2 2PbO + O 2 10. 2C 2 H 6 + 7O 2 4CO 2 + 6H 2 O 1.S 2.DR 3.C 4.SR 5.DR 6.D 7.S 8.SR 9.D 10.C What type of chemical reaction is each of the following?
Complete the reaction… Pb(OH)4 + NaCl ppt??? Pb + NaCl Are you sure about that answer??? AgNO3 + MgCl2 ppt? KOH
Complete the reaction AgCl + Zn Did I catch you again? Al2(SO4)3 + Ca Ba(NO3)2 + Cd3(PO4)2 ppt? Na + O2 CH4 + O2 Say the word equations…
Go to www.creative- chemistry.org.uk/gcse/revision/equations/03.htmwww.creative- chemistry.org.uk/gcse/revision/equations/03.htm You will complete at least 20 problems. Sulfuric acid and powdered sugar https://www.youtube.com/watch?v=ed2AbvQ6ZrQ https://www.youtube.com/watch?v=ed2AbvQ6ZrQ Bozeman: https://www.youtube.com/watch?v=yS8noHTIJ_E https://www.youtube.com/watch?v=yS8noHTIJ_E
Predicting Precipitates Precipitate: Liquid + Liquid = Solid Cloudy Solubility determines formation Solubility chart Soluble means NO precipitate will form!
Will a precipitate form?? Write the products first to determine. Na 2 CO 3 + Ba (NO 3 ) 2 H2SO4 + Pb(OH)2