Chemical Reactions

Reactions The change one or more substances into other substances is a chemical reaction 2H2 + O2  2 H2O A chemical equation needs to be balanced This means you need the same number of atoms on each side of the equation

Mixtures and Solutions A mixture is a combination of 2 or more components that retain their identity A heterogeneous mixture is one that the components are recognizable Soil is an example A homogeneous mixture is one that parts cannot be distinguished, even though they also retain their properties Coffee or Kool Aid is an example Homogeneous mixtures are also called solutions

Acids and Bases An acid is a solution containing a substance that produces hydrogen ions (H+) in water H2O + CO2  H2CO3 Bases produce hydroxide ions (OH-) in water The pH scale measures the hydrogen and hydroxide ions in solutions 0-6 represents an acid, 7 is neutral, and 8-14 is a base