Chemical Reactions Study Guide

Physical Properties

Can be observed without changing the substance; examples include color, shape, mass, texture, and density.

Chemical Properties

Describe how a substance can react with other substances; examples include flammability and ability to rust.

Density Formula

Density is calculated by dividing mass by volume (Density = mass/volume).

Law of Conservation of Matter

States that matter cannot be created or destroyed, only rearranged in chemical reactions.

Signs of a Chemical Reaction

Indications include color change, gas formation, temperature change, and light or sound production.

Balancing Chemical Equations

You can change coefficients, but not subscripts, to balance a chemical equation.

Counting Atoms in a Molecule

Involves examining the chemical formula and applying the distributive property for coefficients.

Substance

Made of only one kind of material with definite properties.

Mixture

Made of two or more substances physically combined.

Controlled Experiment

An experiment where only one variable is changed at a time to ensure valid results.

Physical Changes

Result in appearance changes of a substance; usually reversible, such as ice melting.

Chemical Changes

Result in the creation of a new substance; usually not reversible, such as wood burning.

Lab Safety Procedures

Always wear goggles and gloves, read directions, report spills, keep chemicals closed and labeled.

Unsafe Lab Practices

Never taste or smell unknown chemicals, mix substances without instruction, or run/play in the lab.