[APPLCHE] Chemical Reactions

physical change

changes that occurs in matter that does not result to the formation of new substances

chemical change

Change that occurs in matter that results to the formation of new substances

chemical equations

symbolic representation where the reactant entities are written on the left-hand side and the product entities are written on the right-hand side

coefficients

placed next to the symbols and formula of chemical equations that are values of the stoichiometric numbers or stoichiometric coefficients

net forward reaction

reaction in both directions

stoichiometric relation

equilibrium

(g) or (v)

gas or vapor

(l)

liquid

(s)

solid

(cr)

crystalline

(lc)

liquid crystal

(sln)

solution

(aq)

aqueous solution

(aq, ∞)

aqueous solution at infinite dilution

basic chemical equation

classified according to how atoms rearrange

combination or synthesis

two or more substances combine to form a single product:

A + B → AB

decomposition

A single compound breaks down to form two or more products

AB → A + B

single replacement

A + BC → AC + B

double displacement or metathesis

AB + CD → AD + CB

thermochemical equations

equations which shows whether heat is absorbed (ΔrH>0) from the surroundings or heat is released (ΔrH<0) to the surroundings

endothermic reactions

reactions in which heat is absorbed from the surroundings

A + B + heat → AB

exothermic reaction

reactions in which heat is released to the surroundings

A + B → C + D + heat

ionic equations

equations in which electrolytes are written as dissociated ions as it dissolves and forms in an aqueous solution

electrolytes

substances that conduct electricity through movement of ions and dissociates into cations and anions when dissolved in polar solvents like water

spectator ions

ions that are present in both sides of the ionic equation and do not participate in the reaction

molecular equation

shows dissolved ionic compounds (aq) and undissolved compounds (s) or (g) in neutral formulas

full ionic equation

shows all soluble strong electrolytes as dissociated ions

net ionic equation

eliminates the spectator ions to show only the actual species participating in the reaction

electrochemical equations

equations which describe the transfer of electrons between chemical species either to generate electrical (in galvanic cells) or to drive chemical changes using electrical energy (in electrolytic cells)

half-cell reactions

either the oxidation (loss of electrons) or reduction (gain of electrons) component of a complete redox (oxidation-reduction) reaction

oxidation reaction

shows a reaction in which species increase its oxidation state, resulting to a loss of electron(s)

reduction reaction

shows a reaction in which species decrease its oxidation state, resulting to a gain of electron(s)

net cell reaction

equation resulting in the sum of the two half-cell reactions (oxidation half-cell reaction and reduction half-cell reaction)
Balanced for both mass and charge, and must not contain any free electrons since the electrons lost from the oxidation reaction were consumed by the reduction reaction

(synthesis) basic oxide or basic anhydride (2MgO)

metal + oxygen gas (2Mg + O₂)

(synthesis) acidic oxide or acidic anhydride (SO₂)

non-metal + oxygen gas (S + O₂)

(synthesis) acid (H₂SO₃)

non-metal oxide + water (SO₂ + H₂O)

(synthesis) alkali/base (Mg(OH)₂)

metal oxide + water (MgO + H₂O)

(decomposition) metal + oxygen gas (Hg + ½ O₂)

metal oxide (HgO)

(decomposition) metal oxide + CO₂ (Na₂O + CO₂)

metal carbonates (Na₂CO₃)

(decomposition) metal nitrites + O₂ (NaNO₂+ ½ O₂)

metal nitrates (NaNO₃)

(decomposition) metal carbonate + H₂O + CO₂ (Na₂CO₃ + H₂O + CO₂)

metal bicarbonates (2NaHCO₃)

ZnSO₄ (aq) + Cu (s)

Zn (s) + CuSO₄ (aq) →

Cu(NO₃)₂ (aq) + Ag (s)

Cu (s) + AgNO₃ (aq) →

no reaction

Fe (s) + MgSO₄ (aq) →

no reaction

Sn (s) + NaNO₃ (aq) →

NaOH + ½ H₂ (g)

Na + H₂0 (l) →

Fe₃0₄ + 4H₂ (g)

3 Fe + 4H₂O (v) →

ZnCl₂ + H₂ (g)

Zn + HCl (aq) →

no reaction

Mg + H₂O (l)

no reaction

Cu + H₂O (v)

no reaction

Au +HCl (aq)

halogen displacement reactions

the halogen acts as an oxidizing agent as it reacts with the metal halide

gas-forming reactions

involve reaction between ionic compounds in aqueous solution forming a new compound and a gas or a substance that immediately decomposes into a gas

neutralization reactions

involve reaction of an acid and a base forming salt and water

precipitation reactions

involve reactions between ionic compounds in aqueous solution forming an insoluble product

combustion reactions

involves reaction with oxygen gas forming oxides such as CO, CO₂, H₂O, SO₂, or SO₃.