Inorganic Chemistry Notes

Physical & Chemical Changes

Phases of Matter

Structure of an atom

Chemical Bonding

Chemical bond – force that joins atoms to form a stable substance Compound – substance made of the joined atoms of two or more different elements identified by a chemical formula Ex. CO2, H2O, C6H12O6, NaCl

Types of Chemical Bonds Covalent bonds – when atoms share electrons to form molecules Ex. H2O Ionic bond – formed when ions of opposite charge interact (are attracted to each other) Ex. NaCl Ion – atom or molecule that has gained or lost one or more electrons Cation (aka. positive ion) – has lost electrons, i.e. : K+, Na+, Ca2 Anion (aka negative ion) – has gained electrons, i.e. Cl¯, F¯, O2¯

Types of Chemical Bonds Hydrogen bonds – Weak attractions between polar molecules (i.e. water)

Mixtures

Mixtures Mixtures - combination of substances that can be separated into its individual substances by appropriate physical changes Homogenous mixture – completely uniform in composition, its components are not distinguishable Heterogenous mixture - not uniform in composition, its components are distinguishable; Ex. Salad dressing, concrete

Mixtures Homogenous mixture – completely uniform in composition, its components are not distinguishable Solution - type of homogeneous mixture in which solutes are dissolved in a solvent; Ex. Air, seawater Suspension – type of homogenous mixture in which particles are suspended in another substance; ex. blood, river water

SECTION 2 – WATER AND SOLUTIONS

70% of your body is made of water Water in Living Things 70% of your body is made of water 2/3 of the molecules in your body are water molecules cells are filled with water and surrounded by water water is known as the “universal solvent” Solvent - the substance that dissolves the solute when making a solution Solute - the substance that is being dissolved when making a solution

10 Properties of Water

Water is inorganic—because it does not contain carbon, H2O Water has a set molecular structure— H2O 3. A Water molecule is held together by covalent bonds 4. Water molecules are held to each other by hydrogen bonds +/- charge

Water has a high specific heat 5. Water is polar - because of its uneven distribution of charge; results in most of the other unique properties of water Polar molecules (like water) dissolve polar and ionic molecules (“like dissolves like”) Nonpolar molecules do not dissolve well in water Important in membrane structure and function Water has a high specific heat Water heats slowly and retains heat longer than many other substances Important in helping organisms maintain body temperature through evaporation of water, which carries the heat away O _ H H + +

7. Cohesion and adhesion Water’s polar nature makes it exhibit both cohesion and adhesion Cohesion – attraction between water molecules (hydrogen bonds) causes surface tension causes drops of water to form Adhesion – attraction between a water molecule and another substance causes substances to get wet causes capillary action

Adhesion – things get wet Cohesion – surface tension Adhesion – capillary action Cohesion

liquid water has a density of 1 g/ml - In general, solid water is less dense than liquid water

Periodic Table Number of Protons? Number of Neutrons? Atomic Mass? Atomic Number?

Acids and Bases

Acid – compound that forms hydrogen ions in water Base – compound that forms hydroxide ions in water, or removes hydrogen ions from water pH—(stands for pondus hydrogenii meaning “potential hydrogen”) a value used to express the acidity or alkalinity of a solution

pH scale – measures the concentration of hydrogen ions in solutions; scale of 0 to 14 0 to 6.9 is acidic 7.0 is neutral 7.1 to 14 is basic or alkaline a solution of pH of 3 has 10 times more hydrogen ions than one with a pH of 4

Neutralization - the reaction of an acid with a base, so called because the properties of both the acid and base are diminished or neutralized. Buffer - a solution that resists changes in pH when moderate amounts of acids or bases are added to it. Is your whole body at a pH of 7, or does the pH change from one place to another? What do you think is the purpose of this arrangement? Answer – It changes, not just within a body but within a cell, too. The purpose is to create unique environments, each with a specific purpose. For example, enzymes in the stomach are only functional at a pH between 1 and 2 to prevent them from digesting the body.