Chem U3 Quiz

u3 quiz

What law explains why equations must be balanced?

A: The Law of Conservation of Mass.

What does a coefficient tell you in a chemical equation?

The number of molecules or moles of a substance.

Arrhenius Definition - BASE

If it releases OH⁻ (hydroxide ions) → it’s a base

This definition ONLY works in water.
If there’s no water, Arrhenius doesn’t apply.

Arrhenius Definition- ACID

If it releases H⁺ (hydrogen ions) → it’s an acid

This definition ONLY works in water.
If there’s no water, Arrhenius doesn’t apply.

Brønsted–Lowry

Acid = donates (gives) H⁺

Base = accepts (takes) H⁺

No water required.

Conjugate Pairs- Aggressive Dentists Butchered Raisins

• Acid gives H⁺ → it becomes its conjugate base

• Base takes H⁺ → it becomes its conjugate acid

Relationship between H⁺ and pH

More H⁺ → smaller pH
Less H⁺ → bigger pH

• Strong acid → very low pH (0–1)

• Strong base → very high pH (13–14)

percent error calc

(experimental value - accepted value ) / accepted value * 100

Percent composition

mass of element in compound / total mass of compound * 100

What is a mole ( + molar mass )

• 1 mole = 6.022 × 10²³ particles (atoms, molecules, ions, etc.)

• Units = grams/mole (g/mol)

the relationship between the H+/OH- ions concentration and the pH?

H⁺ goes up → pH goes down
OH⁻ goes up → pH goes up