Chemistry - Chapter 11: Chemical Reactions

Chemical reactions are represented with…

chemical equations

+

Used to separate multiple reactants or products

→

yield sign; separates reactants from products

⇄

replaces the yield sign for reversible reactions that reach equilibrium

(s)

reactant or product in the solid state

(l)

reactant or product in the liquid state

(g)

reactant or product in the gas state

(aq)

reactant or product in an aqueous solution (dissolved in water)

Pt above the →

formula written above the arrow is used as a catalyst in the reaction

△ above the →

triangle indicates that the reaction is being heated

reaction occurring in a natural gas flame

• Word equation: Methane (g) + oxygen (g) → carbon dioxide (g) + water (g)

• Skeleton equation: CH_4(g) + O_2(g) → CO_2(g) + H₂O_(g)

What do you need to do to a skeleton equation?

It’s unbalanced, so you need to add coefficients in front of the chemical formulas as needed to balance the equation.

Synthesis reactions

aka combination reaction, a reaction in which two or more substances react to produce a single product

• A + B → AB

Synthesis reaction of 2 elements

form a compound

• Ex. 2Na_(s) + Cl_2(g) → 2NaCl_(s)

• Ex. Ex. Mg_(s) + Cl_2(g) → MgCl_2(s)

Synthesis reaction of a metal and oxygen

forms the element’s metal oxide

• Ex. 4K_(s) + O_2(l) → 2K₂O_(aq)

Synthesis reaction of a metal oxide and water

forms an aqueous solution of the metal hydroxide

• Ex. CaO_(s) + H₂O_(l) → Ca(OH)_2(aq)