Water and Solutions 6.3

Water’s polarity Water molecules (H20) are polar. When a molecule is polar, it means that it has oppositely charged regions.

Water’s polarity Water’s polarity is what helps it form weak hydrogen bonds.

Mixtures with water Mixture- combination of two or more substances in which each substance retains its individual characteristics and properties. A mixture can be homogenous or heterogenous. Homogenous- the prefix homo- means the same. When a mixture is homogenous, it is completely mixed up Heterogeneous- the prefix heter- means different. When a mixture is heterogeneous, it is not completely mixed up, the individual parts are still separate.

Homogeneous mixtures Solution- this is another name for a homogenous mixture. Think of contact solution, it’s all completely mixed up. Solvent- this is the liquid in which other things dissolve. Water is a good solvent. This would be the water in contact solution. Solute- this is the compound that is dissolved in the liquid. Think of this as the salt that is dissolved in the contact solution.

Mixtures with water pH scale- the scale we use to determine how basic or acidic something is. 1-6.9-> acidic ex. Lemon juice 7-7.9-> neutral ex. Pure water 7.9-14-> basic ex. Milk A buffer is something that can react with an acid or a base to keep it in a certain range.

Mixtures with water

Mixtures with water Base- a substance that releases hydroxide (OH-) ions when it is dissolved in water. Therefore, a solution that has a lot of hydroxide ions in it is basic. Acid- a substance that releases Hydrogen (H+) ions when dissolved in water. Therefore, a solution that has a lot of hydrogen ions in it is acidic.

Key points 6.3 Water is polar, meaning water molecules have different charges on different sides of the molecule. Acids have a ph of 1-6.9 Bases have a pH of 7.9-14