Unit 1: Chemistry

Question 1

Acids

Answer 1

The acidity of a solution is measured by its number of hydrogen ions. You can look at this measure on a pH (potential hydrogen) scale. Acids are hydrogen acid donors.
- lower than 7 on pH scale is acidic
- taste sour
- burning sensation (if you touched it)
- turn blue litmus paper red

Question 2

Bases

Answer 2

Bases are hydrogen receptors. An alkali is a water-soluble base
- above 7 is a base (the scale goes up by ten. An object with pH of 5 is ten times more acidic then an object with pH of 6)
- taste bitter
- feel slippery
- turn red litmus paper blue

Question 3

Law of Conservation of Mass

Answer 3

Matter cannot be created or destroyed in a chemical reaction.
The mass of the reactants = mass of the products
There must be the same number of atoms of each element on both sides of the equation.

Question 4

Synthesis

Answer 4

A + B → AB
Two reactants combine into one product
Mg + O2 –> MgO

Question 5

Decomposition

Answer 5

AB → A + B
One compound breaks into simpler substances

Question 6

Single Displacement

Answer 6

A + BC → AC + B
One element replaces another

Question 7

Double Displacement

Answer 7

AB + CD → AD + CB
Ions in two compounds switch partners

Question 8

Neutralization

Answer 8

• special Double Displacement
  Acid + Base → Salt + Water
  Involves acid and base (look for H⁺ and OH⁻)