Chemistry Regents Review: Moles/Stiochiometry & Unit 4 (week #4)

Concentration

amount of substance in a defined space

Mole Calculations

unit of measurement for the amount of a susbtance

Gram-Formula Mass (GFM)

mass, in grams, of one mole of a compound or element

Solute

a substance dissolved in another substance

Solvent

susbstance in which solute is dissolved in a solution

Mass

the amount of matter present in a sample

Law of Conservation of Mass

• mass is not created or destroyed in chemical reactions

• mass of reactants = mass of products

When you add a solute to water, the…

freezing point decreases and boiling point increases because the number of particle increase

Solution

Homogenous mixture

What do ionic compound makes when dissolved in water?

electrolytes

Why are ionic compounds good conductors of electricity when DISSOLVED?

their ions move freely

Solubility _______ as temperature ________ of ONLY ________

increases & increases & compounds

Once the # of dissolved particles is constant, the solution is…..

saturated

Solubility

measure of max amount of solute that can dissolve in a given amount of solvent at a specific temperature

What happens to gases as temperature increases?

solubility decreases

PPM (parts per million) meaing

very small concentrations

What is the rls btwn molarity and concentration?

Increase M = Increase Concentration

Why is it easier for weaker attractive forces to evaporate?

less energy required to break the IMF

Weak attractive forces have high vapor pressure because…

easir to enter gas phase

Molecular Formula

exact amount of atoms of each element in a substance

Molecular Formula Example

C6H12O6

Empirical Formula

simplified/reduced ratio of elements in a substance

Empirical Formula Example

CH2O

Molecular to Empirical

divided all atoms of the element by the greater whole number that divides evenly into all of them

Empirical to Molecular

1. find GFM of empirical

2. divided the molecular GFM (given) by empirical

3. multiply all atoms of empirical formula by that number

Ionic Naming

metal ions name + non-metal ions name with -ide at the end

If you are trying to name an polyatomic ion…

the second ion ends in -ate

Name AlO3 (ionic)

aluminium oxide

Name K2SO4 (polyatomic)

Postassium Sulfate

Covalent Naming

prefix for the amount of atoms of an element

Name N2O3 (covalent)

dinitrogen trioxide

types of chemcial formulas

• empirical

• molecular

• structural