2.0x Chemical Changes

2026-02-28 16:11

Status: #new

Breaking of chemical bonds on an reactant side and the formation of new chemical bonds on the product side
- Can be considered the rearrangement of atoms

Matter cannot be destroyed nor created when undergoing physical or chemical changes. The total mass of the reactants must equal the total mass of the product which can then be inferred that atoms are only rearranged, but not created nor destroyed.

Word Equations
- $s o d i u m + c h l o r i n e - > s o d i u m c h l o r i d e$
Skeleton Equation
- States all chemicals in a chemical formula.
- Describes stats of matter. Is NOT balance
Balanced chemical equation
- Essentially a balanced Skeleton Equation
Total

Metal Oxides - Solid
Non-Metal Oxide (Gas)
- Exceptions:
  - $H_{2} O_{(a q)}$
  - $S i O_{2 (s)}$
Ammonia ( $N H_{3}$ ) - Gas
All ionic compounds containing alkali metal cations or ammonium are always soluble.
Soluble Cations
- Lead (II), Mercury (I), ammonium
Fluorine is usually NOT soluble.
Hydroxide (basic) are usually insoluble.

Breaks up all aqueous compound and acids
CANNOT break molecules!!!
- Ie. $C a (O H)_{2 (a q)} + 2 H C L_{(a q)} \to C a C l_{2 (a q)} + 2 H_{2} O_{(l)}$
- This becomes (Our total ionic equation):
  - $C a_{(a q)}^{2 +} + 2 O H_{(a q)}^{-} + 2 H_{(a q)}^{+} + 2 C l_{(a q)}^{-} \to C a_{(a q)}^{2 +} + 2 C l_{(a q)}^{-} + 2 H_{2} O_{(l)}$
- We cancel out the spectator ions
  - Ions with same terms across both sides
- This results in:
  - $2 O H_{(a q)}^{-} + 2 H_{(a q)}^{+} \to 2 H_{2} O_{(l)}$
Takeaway:
- The Total Ionic Equation displays all possible ionic equations
- By taking out he spectator ions, this conveniently leads to the Net Ionic Equation (see below)

Lets observe the result of the previous equation AFTER taking out spectator ions
- $2 O H_{(a q)}^{-} + 2 H_{(a q)}^{+} \to 2 H_{2} O_{(l)}$
- Remove the common factors (if there are any)
- $O H_{(a q)}^{-} + H_{(a q)}^{+} \to H_{2} O_{(l)}$
This equation gets rid of spectator ions and shows whats actually going on in an reaction.
- In addition, there can be common factors despite derivations from a fully balanced reaction.

References