Matter

Chemistry

•  Chemistry – the study of the composition, structure, and properties of matter and the changes it undergoes.

•  Branches –  Organic Chemistry– the study of most carbon

containing compounds –  Inorganic – the study of anything that isn’t

organic –  Physical Chemistry – the study of properties

and changes of matter in relation to energy –  Others – Analytical chemistry, Biochemistry,

and Theoretical chemistry

•  Matter – defined as anything that has mass and takes up space

–  Mass vs. Weight •  Mass – the measure of the quantity of

matter –  Not affected by outside forces –  Your mass on the earth and the moon are the

same •  Weight – measures the force of gravity on a

body –  Your weight on the earth and the moon are

different

–  Types of Matter •  Element – Matter that cannot be broken

down into simpler matter by a chemical reaction –  91 naturally occurring elements/ several synthetic

elements –  All samples of the same element have the same

chemical properties

Magnesium Mercury

•  Compounds – 2 or more atoms of different elements chemically combined. –  A compounds physical and chemical

properties differ from the properties of the elements that make it up. »  Water (liquid) – made up of hydrogen and

oxygen (gases) –  All pure samples of a compound will be

chemically the same »  H20, H2S04, etc. “ratio of atoms”

–  Compounds can only be separated by chemical reactions

–  Elements making up a compound have a definite set ratio by mass. The ratio will be the same for any size sample of that compound.

•  Law of Definite Proportions •  Ex. In a 100 g sample of H2O there is

11.2 g of Hydrogen (H) and 88.8 grams of Oxygen (O)

•  How did I get these numbers?

•  How many grams of O would be in a 250 g sample of H2O?

•  Mixtures – 2 or more substances physically combined

–  Each part of the mixture retains it’s original properties

–  Mixtures can be separated physically. (Filter, evaporation, etc.)

•  The composition of a mixture can vary. (no set ratio of atoms or mass)

•  Mixtures can be …. –  Homogeneous – substances uniformly

distributed –  All compounds and elements are homogenous –  Kool –Aid, Lemonade, stainless steel

–  Heterogeneous – parts of the mixture have a different composition

–  Cement, Sand and Gravel

•  Types of Mixtures –  Solution – substances of similar size

evenly distributed. –  Ex. saltwater (salt = solute/ water = solvent)

–  Suspension – Large substances mixed w/ smaller substances

–  Ex. sand and water, blood –  Colloid – mixture between a suspension

and solution –  Most difficult to separate –  Gel – solid state of colloid –  Sol – liquid state of colloid –  Ex. gelatin, cytoplasm