Chemistry Review
Molar mass, conversion, names and symbols
to grams = moles x molar mass
Mass in grams (g)
hint: grams to moles = grams/molar mass and moles
Moles
50
Molar Mass (g/mol)
rounded
80
492
164
3
108
25.8
66.5
18
17
120
6
1.5
0.55
343
137
2.5
12
62
71
16
0.17
3.9
196
441.6
98
138
2
3.2
0.625
Name of element or
compound/symbol
Ammonium nitrate
/NH4NO3
sodium
phosphate/Na3PO4
Water/H2O
Ammonia/NH3
magnesium
sulfate/MgSO4
phosphorous
trichloride /PCl3
nitrogen triflouride/NF3
Methane
/CH4
Sulfuric acid/H2SO4
Potassium
Carbonate
/K2CO3
Naming and Ions: Two elements always end in “ide”, three or more many times end in “ite” or “ate”
Ions are cations with a positive charge, mostly metals like Na+, Mg +2, Al +3, Fe +2 and Fe+3 and NH4+
Or anions with a negative charge, mostly non-metals.
When writing a compound formula with cations and anions, the cation is always written first
So sodium chloride is NaCl, potassium bromide is KBr
Charges of ions in an ionic compound cancel each other out so the compound is neutral, the charge of
the ion becomes its partners subscript
So magnesium nitrate is formed with Mg+2 and NO3- , There will be one magnesium and two nitrates
Mg(NO3)2
For non-metals with non-metals : Use mono, di, tri, tetra, penta, etc. as a prefix of your element in the
compound…except don’t use mono on the first element
So CO2 is carbon dioxide and Cl2O8 is dichlorine octaoxide
Naming acids and bases and information:
Acids (sour, electrolytes, turns most indicators red)always start with Hydrogen except water which is
neutral
1. HCl, HBr, HF are Hydro ______ic acids, where ______is chlor, brom and fluor respectively
2. If a polyatomic anion ends in “ate” = _______ic acid, H2SO4 is sulfuric acid
3. If a polyatomic anion ends in “ite”=_______ous acid, H2SO3 is sulfurous acid
Bases (bitter, slippery, electrolytes, turns most indicators blue)end in hydroxide (OH-) except for NH3
which is ammonia, NaOH is sodium hydroxide, KOH=potassium hydroxide. Acids will give H+ away, Bases
will take the H+. Mixing acid and bases will create water and a salt.
Sometimes acids and bases are reactants, conjugate bases and conjugate acids are products.
HCO3-(aq) + H20(l)  CO3 -2 (aq) + H3O+ (aq), Identify the acid, base, conjugate acid and conjugate base.
HCO3- is the acid, it gives it hydrogen to the base H2O, CO3 -2 is the conjugate base and H3O + is the
conjugate acid.
Acids and Bases are on a pH scale of 0-14, 0 being most acidic and 14 being most basic(alkaline) with 7
being neutral like water.
Strong acids and bases break down into ions more easily, so HCL is strong, pH of 1-2, because it breaks
up into ions more easily while lemon juice ,pH of2, is a weak acid that with ions that don’t break apart as
easily. Strong acids are strong electrolytes.
Metals will react with acids if they are above hydrogen in the activity series table. These form metal
salts and hydrogen gas(H2)
When you move up and down the pH scale, the change in pH is a multiple of 10x, so pH of 4 is 10X more
acidic than pH of 5 and 100x more than pH of 6. Use 7 for neutrality, so pH of 12 is 10x more basic than
pH of 11.
pH=-log[H+] and pOH= -log[OH-], pH + pOH =14
Balanced equations: As per Mr. Guch : Subcripts down below can not be changed, coefficients on the
side can be changed to reach a balanced equation and conservation of mass. Reactant(left side) must
equal Product( right side).
For each element =coefficient x subscript
1)
__2_ NaNO3 + ___ PbO  ___ Pb(NO3)2 + ___ Na2O
2)
__6_ AgI + ___ Fe2(CO3)3  _2__ FeI3 + _3__ Ag2CO3
3)
___ C2H4O2 + __2_ O2  __2_ CO2 + __2_ H2O
4)
___ ZnSO4 + ___ Li2CO3  ___ ZnCO3 + ___ Li2SO4
5)
___ V2O5 + __5_ CaS  __5_ CaO + ___ V2S5
6)
___ Mn(NO2)2 + ___ BeCl2  ___ Be(NO2)2 + ___ MnCl2
7)
_3__ AgBr + ___ GaPO4  ___ Ag3PO4 + ___ GaBr3
8)
__3_ H2SO4 + __2_ B(OH)3  __ B2(SO4)3 + __6_ H2O
Types of equations or types of reactions:
1. Decomposition: One reactant breaking down into elements or other compounds:
2 PbSO4  2 PbSO3 + 1 O2
2. Combination or synthesis: elements and compounds mixing to form one product
1S8 + 8O2 8SO2
3. Single (re)displacement: The single element(or diatomic) will replace another element in a
compound
3 Mg + 1 Fe2O3  2 Fe + 3 MgO, so Mg replaces Fe only because the single magnesium is above
iron in the activity series chart, so the reverse reaction would not occur. If the single is down
below, the reaction will not go
4. Double (re)displacement: The cations or first element switch places . This will only take place if
one of the products are insoluble or a solid. From the solubility chart
3 NaBr + 1 H3PO4  1 Na3PO4 + 3 HBr, Na and H switch places
Or
3 Ca(OH)2 + 1 Al2(SO4)3  3 CaSO4 + 2 Al(OH)3 , Ca and Al switch places
Acid base is part of double displacement, one product is always water
1HCl + 1NaOH1H2O + 1NaCl, H and Na switch places
5. Combustion : (Anything that burns in oxygen), But we will use hydrocarbons or
alcohols(hydrocarbon with an oxygen in the formula) burning in oxygen will produce water and
carbon dioxide
1CH4 + 2O2  2H2O + 1CO2
or
2CH3OH +3O2  4H2O + 2CO2
Oxidation /Reduction:
LEO goes GER : Electrons must equal charge with the help of coefficients
Lose electrons oxidation Mg Mg+2 + 2e-,
Gain electrons reduction
lose negativity, element becomes more positive
S + 2e-  S-2 gain electrons, element becomes more negative
In an equation: 2Ag+ + Cu  Cu+2 + 2 Ag, so Cu Cu+2 + 2e- (LEO)& 2Ag+ + 2e-  2Ag(GER)
Note: single replacement reactions only produce products when the single metal in the reactant is
more active than the metal in the compound in the reactant.
1. In the equation: Fe + CuSO4  predict products, balance the equation and determine what element
is reduced and what element is oxidized. Balance the redox reaction.
Fe + CuSO4  Cu + FeSO4 ;
Fe Fe +2 + 2e- is LEO and Cu +2 + 2 e- Cu is GER
…so Fe + Cu+2 + 2e-  Cu + Fe+2 + 2e2. In the equation: AgNO3 + Cu  predict products, balance the equation and determine what element
is reduced and what element is oxidized. Balance the redox reaction.
2AgNO3 + Cu  2Ag + Cu(NO3)2 ; 2Ag+ + 2e-  Ag is GER and Cu Cu+2 + 2e- is LEO
….so 2Ag+ + Cu + 2e- 2Ag + Cu+2 + 2e-
An Ox sat on a big Red Cat: anode is the location of oxidation, cathode is the location of reduction.
The greatest electrical potential happens when two metals are further apart on the activity series.
Electron flow in an electrochemical cell will move from higher to lower activity of metals in the
activity series.
Gas Laws:
Always convert Celsius to Kelvin so 0C + 273 = K
1. pressure and temperature are directly proportional
2. volume and temperature are directly proportional
3. pressure and volume are indirectly proportional
P=Pressure in atm or kPa
T=temperature in K
n=moles
L/22.4 L/mol = mol, mol x 22.4L/mol = L
22.4 L/mol
R= .0821Lxatm/Kxmol using atm for pressure or 8.31 LxkPa/Kxmol using kPa for pressure
V= volume in Liters,
1000mL = 1 Liter
P1xV1/T1=P2xV2/T2 is Combined Gas Law
PxV=nxRxT
n (moles) x molar mass = grams
Addison Wesley questions
1. The pressure on 2.5L of anesthetic gas changes from 105kPa to 40.5kPa. What will be the new
volume if the temperature remains constant? P1 x V1 = P2 x V2
V2= 6.5L
2. A gas has a volume of 4.00 L at 2 atm. It expands to a volume of 12.0L, what will be the new
pressure at constant temperature?P1 x V1 = P2 x V2
P2 = 0.67 atm
0
3. A sample of gas occupies 6.80 L at 325 C, what will be the volume at 250C if pressure is
constant? 325 + 273 =598K and 25 + 273 = 298K; V1/T1 = V2/T2
V2= 3.39 L
0
4. What volume will 12.0 g of oxygen gas occupy at 25 C and a pressure of .5 atm?
P x V = n x R x T, T= 25 + 273 = 298K , 12 g/ 32g/mol =0.375 moles V = 18.3 L
5. If pressure decreases, Volume does what? increases
6. If temperature increases, pressure does what? increases
Thermochemistry:
Specific Heat Capacity: The lower specific heat the faster an object heats up, the faster it cools down.
Water has the highest specific heat capacity at 4.184 J/gx0C. It will take the longest to heat up and
cool down than most substances. The symbol is C
Three types of heat transfer : conduction=surface to surface; convection=circulation of heat and
radiation=heat from an outside source like the sun.
Heat always travel from a hotter surface to a cooler surface
Enthalpy is heat at a constant pressure
Entropy is the measure of disorder of a system, the higher disorder, the greater the entropy.
Exothermic=heat released ex: freezing or condensing; Exothermic reactions take less activation
energy and the potential energy of reactants is more than potential energy of the products. Heat is
expressed as a negative unit in Joules or kilojoules.
Endothermic=heat absorbed
ex: melting or boiling; Endothermic reactions take more activation
energy and the potential of the reactants is less than the potential energy of the products. Heat is
expressed as a positive unit in Joules or kilojoules.
Phase has a change in temperature and C=q/mxT or q=mxT xC formula is used
C=specific heat in J/gx0C
q= heat in Joules(J)
m=mass in grams(g)
T=temp final – temp initial (change in temp)in(0C)
1000J = 1 kJ
Phase Change is the flatline, no temperature change, this is just conversion from kJ to g or g to kJ
From Addison Wesley:
1. When 435 J of heat is added to 3.4 g of olive oil at 210C and then heated to 850C what is the
specific heat of olive oil? C = q/mx T
C= 2.0 j/g x 0C
2. A 1.55 g piece of steel with a temperature of 520C is dropped in water with an initial
temperature of 250C. The water temperature increases to 280C, how much heat was produced.
The specific heat (C) of water = 4.184J/gx0C
q= m x C X T q= 19.4 J
0
3. How many grams of ice will be melted at 0 C when an additional 3kJ of heat is added to the
system? Heat of fusion is 6.01 kJ/ mol
KJ / H x molar mass
8.98 g
4. How many kJ of heat is absorbed when 63.7 g of water is converted to steam at 1000C? heat of
vaporization is 40.7 kJ/mol
g/ molar mass x H
144 kJ
What increases rates of reaction: larger surface area like grinding up a material, higher temperature,
catalysts (don’t mix chemically) and increased concentration using a 6M instead of 1M
Solids dissolve best when heated, have greater surface area or stirred. Gases dissolve best with high
pressure or solution is cold.
Everyone’s favorite Stoichiometry:
Steps: 1. grams A to mole of A, 2. Mole A to mole B ratio, 3. Mole B to grams of B
Grams to moles: grams given/molar mass=moles
Mole to mole ratio: new mole/original balanced equation mole = multiplier, multiply all moles in
balanced equation by the multiplier to get new moles for the entire equation
Moles to grams: moles x molar mass=grams
Liters to moles: Liters given/22.4 L/mol or moles to Liters: moles x 22.4 L/mol
Addison Wesley examples:
1. Acetylene gas(C2H2) and calcium hydroxide (Ca(OH)2) is produced by adding water to calcium
carbide (CaC2). How many grams of acetylene gas are produced by adding water to 5.00 g of
CaC2?
CaC2 + 2 H2O C2H2 + Ca(OH)2
5g/64g/mol =0.08 moles CaC2 = 0.08 moles C2H2, 0.08 moles x 26g/mol = 2.08 g C2H2
2. Using the above equation, how many moles of CaC2 are needed to react with 49.0 g H2O?
49.0g/18g/mol = 2.72 moles H2O = 1.36 moles CaC2
3. Carbon monoxide will burn in oxygen to form carbon dioxide, how many liters of oxygen are
required to burn 3.86 L of carbon monoxide?
2CO + O2 2CO2 3.86 L CO = 1.93 L O2 Liter to Liter = Mole to mole
4. Phosphorous(P4) and hydrogen will combine to form Phosphine(PH3), how many liter of
phosphine are formed when 0.42L of hydrogen reacts with phosphorous?
P4 + 6H2 4PH3 .042 L H2 = .028 L PH3
5. Using the equation from question one, if 2.6 moles of water are used and 6.3 moles of CaC2 are
used, which reactant is limiting and how many grams of C2H2 are produced?
Using 2.6 moles of H2O, you would need 1.3 moles of CaC2, which you have with 5 moles excess
of CaC2. 1.3 moles of CaC2 = 1.3 moles of C2H2, 1.3 moles C2H2 x 26 g/mol = 33.8 g