Chemistry 101 First exam

Polyatomic ion + ideal gas laws

Ammonium

NH_4⁺

Hydroxide

OH^-

Nitrate

NO₃^-

Nitrite

NO₂^-

Sulfate

SO₄^2-

Sulfite

SO₃^2-

Hydrogen Sulfate(bisulfate)

HSO₄^-

Hydrogen Sulfite(bisulfite)

HSO₃^-

Carbonate

CO₃^2-

Hydrogen carbonate(bicarbonate)

HCO₃^-

Phosphate

PO₄^3-

Acetate

C₂H₃O₂^-

Cyanide

CN^-

Cyanate

OCN^-

Thiocyanate

SCN^-

Permanganate

MnO₄^-

Chromate

CrO₄^2-

Dichromate

Cr₂O₇^2-

Hypochlorite

ClO^-

Chlorite

ClO₂^-

Chlorate

ClO₃^-

Perchlorate

ClO₄^-

Peroxide

O₂^2-

The ideal gas law

PV = nRT

When to use it: Use the ideal gas law when you know three of the four variables and need to find the fourth, or when the problem gives pressure, volume, moles, and temperature in a single state.

Example: Find the volume of 2.0 mol of gas at 1.5 atm and 300 K.

V=nRT

V = nRT/P

V = (2.00)(0.08206)(300)/1.5

Variables: P, V, n, R, T

p = pressure(atm)

V = volume(L)

n = moles

R = gas constant (0.08206 L·atm/(mol·K))

T = temperature (K)

Boyle’s Law

P₁V₁ = P₂V₂

When to use: The problem involves pressure and volume, and the temperature does not change.

• Pressure increases → Volume decreases.

• Pressure decreases → Volume increases.

Charle’s Law

V₁/T₁ = V₂/T₂

When to use: The problem involves volume and temperature, and pressure stays constant.

• Temperature increases → Volume increases.

• Temperature decreases → Volume decreases.

Note what to do to go from C to K

and K to C

K = C + 273

C = k -273

Combined Gas Laws

P₁V₁/T₁ = P₂V₂/T₂
When to use it: When pressure, volume, and temperature change, but the amount of gas (moles) stays constant.

Gay-Lussac’s

P₁/T₁ = P₂/T₂
You have P and T and Volume stays the same

Avagodro’s Law

V₁/n₁ = V₂ n₂

_{You have volume and moles and P and T stay constant}