Matter and Change Chapter 2

Properties of matter Mass: measure of the amount of matter Volume: measure of the space occupied Extensive property: depends on the amount of matter Intensive property: depends on the type of matter Substance: matter that has uniform and definite composition Properties of matter

States of Matter Solid: definite shape and volume Copyright1994 General Atomics Solid: definite shape and volume Liquid: indefinite shape and definite volume Gas: indefinite shape and volume Vapor: gaseous state of substance that is generally a liquid at room temperature Plasma: made up of groups of positively and negatively charged particles In neon gas, the electrons are all bound to the nucleus. In neon plasma, the electrons are free to move around the system. States of Matter Copyright1994 General Atomics

Quality or condition of a substance that can be observed or measured without changing the substance’s composition Hardness, color, conductivity, malleability Physical change: some properties of the material change, but the composition does not. Reversible or Irreversible Boil, freeze, melt, condense, break, cut, crush Physical Property

Elements and Compounds Element: simplest form of matter that has a unique set of properties Hydrogen, oxygen, carbon Compound: substance that contains 2 or more different elements chemically combined. Water, sugar, carbon dioxide Compounds can be broken down into simpler substances by chemical means, but elements cannot. Elements and Compounds

Chemical property: ability of a substance to undergo a specific chemical change. Chemical change: change that produces matter with a different composition than the original matter. Burn, rot, rust, ferment, explode The composition of matter always changes. Chemical reaction: reactant (start) and product (end) Chemical Change

Signs of chemical change Transfer of energy Change in color Production of a gas Formation of a precipitate (solid that forms and settles out of liquid) Curds (solid) and whey (liquid) Signs of chemical change

During any chemical reaction, the mass of the products is always equal to the mass of the reactants. Conservation of mass: in any physical change or chemical reaction, mass is conserved. Conservation of Mass

Mixtures Mixture: physical blend of two or more components. Heterogeneous: composition is not uniform (two or more phases) Chicken noodle soup Curdled milk Homogeneous(solution): composition is uniform throughout (1 phase) Milk Green ink Phase: any part of a sample with uniform composition and properties Mixtures

Differences in physical properties can be used to separate mixtures. Filtration and distillation Separating Mixtures