Mini review for midterm 1 NB: This does not cover all material!

Units, Conversions, Powers of 10, Prefixes Errors: Sig Figs, Error propagation Statistics: Normal distribution, t-test, Q-test Equilibrium: Constant, K sp, K H, K w, separation by precipitation, acids & bases Titration:v e (very) Rough outline

Molarity = Moles of solute/Liters of Solution (M) Molality = Moles of solute/Kg of Solvent (m) Mole Fraction = Moles solute/total number of moles Mass % = Mass solute/total mass x 100 Volume % = volume solute/total volume x 100 ppm = parts per million * ppb = parts per billion * Chemical concentrations * mass for solutions, volume for gasses

Random error Systematic error

significant figure: The number of significant digits in a quantity is the minimum number of digits needed to express the quantity in scientific notation..

The real rule: The first uncertain figure is the last significant figure. TIP: In our calculations, we retain extra insignificant digits and round off only at the end.

For systematic uncertainty, we add the uncertainties of each term in a sum or difference.

mean Standard deviation

A Gaussian curve in which μ = 0 and σ = 1. A Gaussian curve whose area is unity is called a normal error curve. In this case, the abscissa, x, is equal to z, defined as z = (x − μ)/σ.

0.11/0.2 = 0.55 For 5 measurements Q = 0.65 So…….. KEEP!

Standard addition

Internal standard

Standard addition calibration (-blanks)

K IS DIMENSIONLESS! Concentrations in mol/liter (M) pressures in atmospheres (atm) ignore solids ignore solvents

REVERSE REACTION  reciprocal K ADD REACTIONS  Multiply Ks LE CHATELIER’S PRINCIPLE

SOLUBILITY PRODUCT Ksp

COMMON ION EFFECT Ksp = [Ca 2+ ] 3 [PO 4 3- ] 2 = 1.0 x = (3x) 3 ( x) 2 = 1.0 x

When (BrO 3 — ) is added to a solution containing equal concentrations of Ag + and Pb 2 +, which will precipitate first and why? Ksp = 5.49 x for AgBrO 3 Ksp = 3.23 x for Pb(BrO 3 ) 2 SOLUBILITY PRODUCT Ksp SEPARATION BY PRECIPITATION Stoichiometry! BrO 3 ¯