Chemistry Week 4

Formula Mass

• Sum of the atomic mass of all atoms involved in substances formula

Molar Mass

• Mass in grams of 1 mole of a substance

• Same magnitude as amu

• Notated as “g/mol”

Mole

• A measurement of space

• Equivalent to 6.02214179 × 10²³ items

Converting between Mass in Grams and Number of Atoms in Molecule

• Standard dimensional analysis

• Move grams to mol. then use avagato’s number (6.022×10²³) to move from mol. to atoms

Solution

• Homogenous mixture of two or more substances

• Contains solvent and solute as part of its make-up

Solvent

• Part of a solution

• Makes up the majority of the solution

Solute

• Part of a solution

• Makes up a minority of the solution

Molarity

• The amount of moles of a solute present in 1 liter of a solution

• Smaller number means more diluted, bigger number more concentrated

Converting between Volume and Moles

• The solutions specific molarity can be used since it sets 1 liter equal to a set amount of moles

Preparing Solution

• Method 1: Preparing a solution from scratch

1. Measure out the solute

2. Add the solute to a volumetric flask

3. Add solvent to the volumetric flask till reaching desired volume

• Method 2: Preparing a solution by diluting another solution

1. Start with solution

2. Add appropriate amount of solvent

Dilution Equation

• Used in method 2 (preparing a solution by diluting another solution)

• Helps find proper amount of solvent to add to reach a desired concentration

Equation: (Mstock solution)(Vstock solution)=(Mdiluted solution)(Mdiluted volume)

Chemical Reaction

• A process by which one or more substances (reactants) are converted to one or more different substances (products)

Chemical Equation

• A paper representation of the chemical reaction taking place

• Reactants on the left products on the right

Balancing Chemical Equations

1. Write chemical formulas for all reactants and products

2. Start with elements other than H to O , balance atoms in compounds before balancing those in atoms pure elements

3. Then balance atoms that appear in pure substances

4. If equation contains coefficient fraction multiply everything by denominator to clear it