Chemistry SOL Study Guide

Percent Error
(measured-standard)/standard X 100 = (known-found)/known X 100
Ideal Gas Law
PV = nRT (or if the question has V & moles: 22.4 liters/mole at STP)
Boyle’s Law
P₁V₁= P₂V₂
“kinetic molecular theory of gases”
Charles’ Law
V₁/T₁ = V₂/T₂ (in Kelvin)
Kelvin Temperature
°C + 273
Molarity
moles/liters
Density
Mass/Volume
Partial Pressures
Add up to Dalton’s law
Ptotal = P₁ + P₂ + P₃+ etc.
Heat Energy (enthalpy)
H = (Mass)(ΔT)(c)
Heat of Fusion (Vaporization)
(Mass)(Heat of Fusion)
Accuracy
How close a measurement is to the correct answer (the standard)
Precision
How closely measurements agree with each other
Ammonium
NH4⁺¹
Hydroxide
OH⁻¹
Nitrate
NO3⁻¹
Carbonate
CO3⁻²
Sulfate
SO4⁻²
Phosphate
PO4⁻³
Group Names
Alkali Metals (+1) Alkaline Earth Metals (+2) Halogens (-1) Noble Gases
Diatomic Gases
B₂R₂I₂N₂Cl₂H₂O₂F₂
Isotopes
Atoms with the same atomic number (protons) but different masses (neutrons)
Half Life
Example: If the half life is 12 years, how many out of 512 original grams remain after 48 years?
48/12 = 4 half lives. 512 → 256 → 128 → 64 → 32
Synthesis (Direct Combination)
A + B = C
Decomposition
A = B + C
Single Displacement
Element + Compound + Other Element + Compound
Combustion of Hydrocarbon
C₅H₁₂ + 8O₂ = 5CO₂ + 5H₂O
Neutralization
HCl + NaOH = NaCl + H₂O
Significant Figures (Addition/Subtraction)
When adding or subtracting sig figs. look at decimal position: 3.123 + 24.5 = 27.6
Significant Figures (Multiplication/Division)
When multiplying or dividing, use the least number of sig figs: 23.045 X 2.1 – 48.3945 = 48
SI Units
Kilo hecto deka unit deci centi milli micro nano pico
Writing Formulas
When writing formulas, criss cross the oxidation numbers: calcium Ca⁺² chloride Cl⁻¹ becomes CaCl₂
Acid Ions and pH
hydrogen H⁺ and pH below 7
pH + pOH = 14
Base Ions and pH
hydroxide OH⁻ and pH above 7
Equilibrium Expression
For aA(s) + bB(g) ⇌cC(aq) + dD(g)
K = (C)^c (D)^d/(A)^a(B)^b
Combined Gas Law
P1V1/T2 = P2V2/T2