Concept 1: Balancing Reactions

List examples of evidence that a chemical reaction has occurred.

- Release of light - Temperature change - Odor change - Sudden color change - Gas is given off - Sudden appearance of a solid (called a precipitate)

List three examples of chemical changes.

Burning, rusting, & decomposition.

List the number of atoms of each element in the compounds below: a.) Ca3(PO4)2

Calcium: 3 atoms Phosphorus: 2 atoms Oxygen: 8 atoms

List the number of atoms of each element in the compounds below: d.) 2CO2

Carbon: 2 atoms Oxygen: 4 atoms

What numbers can be changed to balance a chemical reaction? What numbers cannot be changed?

Coefficients.

Aqueous

Dissolved in water.

Products

Ending substances; what is made.

List the number of atoms of each element in the compounds below: b.) 2Mg(OH)2

Magnesium: 2 atoms Oxygen: 4 atoms Hydrogen: 4 atoms

Explain the Law of Conservation of Mass and how it relates to the amount of reactants and products in a chemical reaction.

Matter can neither be created or destroyed, it can only change forms. Therefore the mass of the reactants must equal the mass of the products.

Given an example of a natural resource that can be chemically changed to make a synthetic resource and describe its impact on society.

Petroleum, which is pumped out of the earth, is chemically changed to become plastic. This is what makes plastic a synthetic resource. Toxic additives are often added to plastic in order to improve its properties. Many of these additives do not bind to the chemical chain of plastic which means they can be released in the environment when exposed to atmospheric conditions. These additives can be absorbed by the skin, evaporate into the air, or absorbed via the food or drinks we consume. The additives of plastic are all highly toxic in nature, which means they're extremely harmful to human health.

Chemical reaction

Process by which the atoms of one or more substances are rearranged to form different substances.

Balance the following reactions: a.) AlBr3 + K2SO4 = KBr + Al2(SO4)3

Reactants: Al = 1 * 2 = 2 Br = 3 * 2 = 6 K = 2 * 3 = 6 SO4 = 1 * 3 = 3 Products: Al = 2 Br = 1 * 6 = 6 K = 1 * 6 = 6 SO4 = 3

Balance the following reactions: b.) Al + O2 = Al2O3

Reactants: Al = 1 * 4 = 4 O = 2 * 3 = 6 Products: Al = 2 * 2 = 4 O = 3 * 2 = 6

Balance the following reactions: e.) C4H10 + O2 = CO2 + H2O

Reactants: C = 4 H = 10 O = 2 * 13/2 = 13 Products: C = 1 * 4 = 4 H = 2 * 5 = 10 O = 8 + 5 = 13

Balance the following reactions: c.) LiCl + Br2 = LiBr + Cl2

Reactants: Li = 1 * 2 = 2 Cl = 1 * 2 = 2 Br = 2 Products: Li = 1 * 2 = 2 Br = 1 * 2 = 2 Cl = 2

Balance the following reactions: d.) NF3 = N2 + F2

Reactants: N = 2 F = 2 * 3 = 6 Products: N = 1 * 2 = 2 F = 3 * 2 = 6

Balance the following reactions: f.) Pb(OH)2 + HCl = H2O + PbCl2

Reactants: Pb = 1 O = 2 H = 2 + 2 = 4 Cl = 1 * 2 = 2 Products: Pb = 1 O = 2 H = 2 * 2 = 4 Cl = 2

List the number of atoms of each element in the compounds below: c.) 6NaCl

Sodium: 6 atoms Chlorine: 6 atoms

Reactants

Starting substances; "ingredients".