FINAL EXAM- Reactions and reaction types Flashcards
Law of conservation of mass
atoms are neither created nor destroyed in a chemical change
Composition
aka synthesis. Many reactants⇒one product. Opposite of decomposition
types of composition
- 2 types
- Metals with Halogens- Ex. Na(s)+Cl2(g)⇒2NaCl(s)
- With oxides (end in O)- Ex. CaO(s)+H2O(l)⇒Ca(OH)2(s)
Decomposition
One reactant⇒many products
Types of decomposition
- 6 types
a) Electrolysis - Use electricity to break the bond
- Ex. H2O(l)⇒2H2(g)+O2(g)
b) Binary Decompositon - Take elements in compound and break them apart
- Ex. 2HgO(s)⇒2Hg(l)+O2(g)
c) Metal Carbonate breaks to form metal oxide+carbondioxide - Ex. CaCO3(s)⇒(Δ above arrow) CaO(s)+CO2(g)
d) Metal hydroxide to form metal + water - Ex. Ca(OH)2(s)⇒(Δ above arrow)CaO(s)=+H2O(l)
e) Metal chlorate to form a metal chloride and oxygen - Ex. 2KClO3(s)⇒2KCl(s)+3O2(g)
f) Tertiary acid to form an oxide and water - Ex. H2CO3⇒⇐CO2(g)+H2O(l)
- ⇒⇐=could go both ways (not specific to this type of reaction, just in general)
Single replacement
When there’s an element and a compound that form an element and a compound and the element replaces its like element in the compound, activity series permitted.
- X+AB⇒AX+B
- X+AB⇒XB+A
- Both above are cation replacements
- Y+AB⇒AY+B
- Above is anion replacement
- Cation replacement- metal replaces metal
- Anion replacement- nonmetal replaces nonmetal
- Use activity series of elements to determine if an element can replace or not
- Ex. Li+NiO⇒Li2O+2Ni
- Metals fight metals and nonmetals fight nonmetals
- Metal and nonmetal always together
- Whichever element is higher on the list wins the fight
- Ex. BaS+Mg⇒NR (no reaction) because Ba is higher on the list so he wins the fight and gets to keep S
- Ex. F2+NaBr⇒NaF+Br2 because F is higher on the list and wins the fight. F2 and Br2 because they are diatomic elements
Double replacement
- 2 compounds for both reactants and products, peaceful switch with no fight.
- AB+XY⇒AY+XB
- Positive/metal is always written first
- Ex. 2NaCl(aq)+Pb(NO3)2(aq)⇒2NaNO3(aq)+PbCl2(s)
- Compound for both reactants and products
Neutralization
aka water forming.
- Type of Double replacement
- Acid+Base⇒Salt+water
- HX+YOH⇒YX + HOH
- Acids start with H (except water) and bases end in OH
- In chemistry, salt is all ionic compounds except acids and base
- Ex. HCl(aq)+KOH(aq)⇒KCl(aq)+HOH(l)
- Ex. 2H(NO)3+Ca(OH)2(aq)⇒2HOH(l)+Ca(NO3)2(aq)
Combustion
- Complete Combustion
- Hydrocarbon (H/C/O) + (excess) Oxygen ⇒(Δ above arrow) Carbon Dioxide+water
- Ex. C2H5OH+O2⇒CO2+H2O
- Incomplete combustion
- Hydrocarbon+(limited)O2⇒CO+H2O (carbon monoxide) or C+H2O(carbon)
Solubility rules
Chart that allows you to determine if a compound is soluble in water
Products
A substance that forms in a chemical reaction
Reactants
a substance or molecule that participates in a chemical reaction
Coefficients
(big number in front of the substance symbol)= number of particles in the substance, used to balance.
Endothermic reaction
Energy+reactants⇒products=endothermic
Exothermic reaction
Reactants⇒Products+Energy=exothermic
Symbols in reactions
- Reactants yield sign ⇒ products
- Plus sign separates reactants/products
- S=Solid
- L=Liquid
- G=Glas
- Aq=aqueous- dissolved in water- water doesn’t take place in the reaction
- Coefficient- (big number in front of the substance symbol)= number of particles in the substance
- Subscripts- used to write the formula corrects so that we have a net charge of zero
- Catalyst- speeds up the reaction without changing its structure
- up arrow indicates g, don’t need to put it in parenthesis
- Sometimes down is used instead of (s) for a precipitate, don’t put in parenthesis
- Δ=add heat for reaction to occur
Know how to balance reactions from words and symbols
- Coefficients are added in front of molecules, formula units, or atoms to balance the total number of each atoms in the equation.
- Ex. 6Li+Sr3N2⇒2Li3N+3Sr
- Ex. 2C8H18+25O2⇒16CO2+18H2O
- Originally C8H18+25/2 O2⇒8CO2+9H2O
- In this case, everything was doubled
- When writing compound, make sure metal/+ goes first, then nonmetal/-
Know how to determine reaction type
- Many reactions ⇒one product= synthesis
- One reactant⇒many products=Decomposition
- Element+compound⇒ Element+compound=single replacement
- 2 compounds for both reactants and products=double replacement
- Acid+Base⇒Salt+water= water forming/neutralization
- Hydrocarbon (H/C/O) + (excess) Oxygen ⇒(Δ above arrow) Carbon Dioxide+water= combustion
Predict the products in a reaction
- Determine reaction type from reactants
- Follow pattern to determine products
- Write formulas for products correctly (use subscripts)
- Balance equation using coefficients
Know how to indicate an exothermic or endothermic reaction in a balanced equation
- Indicate an exothermic reaction by having energy as one of your products
- Indicate an endothermic reaction by having energy as one of your reactants
Determining phase of matter
- All ionic compounds are solids at room temperate unless there’s water around and they are soluble
- Ionic= cation (+) + Anion (-)
- All metals besides mercury are solids at room temperature. Ex. Li(s)
- Not all nonmetals are gases, just the ones on Mrs. Howards period table. Ex. O2(g)
- Nobel gases are always gases. Ex. Ne(g)
- Always check chart when possible to determine solubility
