Aim: What is matter? Do Now: A graduated cylinder has a mass of 80 g when empty. When 20 mL of water is added, the graduated cylinder has a mass of 100 g. If a stone is added to the graduated cylinder, the water level rises to 45 mL and the total mass is now 156 g. What is the density of the stone?

What is Chemistry? Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.

Properties of Matter Extensive properties are properties that depend on the amount of matter in a sample Mass and volume are examples of extensive properties Intensive properties are properties that depend on the type of matter in a sample, not the amount of matter (i.e., density)

Three States of Matter Particles are arranged in a fixed pattern; are packed closely together. Particles vibrate about their fixed position. Particles are packed, but in an unorderly manner, but particles are able to move about; are less close to one another (as compared to solid). Particles are spread widely, free to move anywhere; are far apart. Particles move freely and randomly.

Physical change vs. Chemical Change Physical Change Some properties of a material change, but the composition of the material does not change Can be classified as reversible or irreversible New product is not formed Examples: aluminum foil is cut in half, water evaporates from the surface of the ocean, juice freezes Chemical Change The composition of the matter always changes Produce new substances with different chemical make-ups and properties. Examples: milk goes sour, gasoline is ignited, your body digests food, metal rusts

Mixtures A mixture is a physical blend of two or more components. Heterogeneous mixtures are a mixture in which the composition is not uniform throughout. Oil and vinegar, chicken noodle soup Homogeneous mixtures or solutions are mixtures in which the composition is uniform throughout. oil, vinegar, cup of coffee, salt water

Separating Mixtures: Filtration Filtration is a method for separating a mixture of undissolved solid from a liquid.

Separating Mixtures: Chromatography This is good for separating dissolved substances that have different colors, such as inks and plant dyes

Separating Mixtures: Evaporation This is good for separating a soluble (dissolved) solid from a liquid.

Separating Mixtures: Distillation This is good for separating a liquid from a solution. For example, water can be separated from salty water by simple distillation. This method works because the water evaporates from the solution, but is then cooled and condensed into a separate container. The salt does not evaporate and so it stays behind.

Elements and Compounds An element is the simplest form of matter that has a unique set of properties. Oxygen, hydrogen A compound is a substance that contains two or more different elements chemically combined in a fixed portion. Salt, sugar Compounds can be broken down into simpler substances by chemical means, but elements cannot.

- Particles are not uniformly distributed. Particles are physically combined. -Particles are uniformly distributed. Particles are physically combined. -Simplest form of matter. Ex: O 2 -Two or more different elements chemically combined. Ex: H 2 O yes

Sample Problems Which substance can not be decomposed into simpler substances? (1) ammonia (NH 3 ) (2) aluminum (Al) (3)methane (CH 4 ) (4)methanol (CH 3 OH)

Sample Problems cont. Which statement describes a characteristic of all compounds? (1) Compounds contain one element, only. (2) Compounds contain two elements, only. (3) Compounds can be decomposed by chemical means. (4) Compounds can be decomposed by physical means.

Sample Problems cont. Which formula represents a binary (two different types of elements) compound? (1) NH 4 NO 3 (2) CH 4 (3) CH 3 COCH 3 (4) CaCO 3

Sample Problems cont. An example of a heterogeneous (can tell apart the different parts in the mixture) mixture is: (1) soil (2) sugar (3) carbon monoxide (4) carbon dioxide