Chemistry Chapter 1 Test Notes

Chemistry 3rd Week Test Notes Physical properties of metals are color, luster, ductility and malleability. Models are used to understand the submicroscopic world. Elements can’t be broken down into simpler substances; the atom is the smallest unit that retains the properties of the element. Pure substances are composed of only one type of matter. Examples: water, sugar, gold, silver, propane, etc. Indication of a chemical change is heat, light, and bubbles. Chemical formula examples: NaCl, H2O, CO2, H2SO4. Density is determined by mass/volume. Typical densities are from .1--3.0 g/ml. Atoms are submicroscopic. The submicroscopic combination and arrangement of atoms determines the substance. Examples: H2O and H2O2, CH4 and C2H2. Some examples of models: maps, wind tunnel, and sculpture. Examples of physical changes: melting, freezing, and evaporating. Some physical properties are melting/freezing points, color, and texture. An important characteristic of chemical compounds is that they always form in the same fixed proportion every time. Meaning water is always 2 H atoms and 1 O atom, propane is always 3 C atoms and 8 H atoms, etc. The instability of hydrogen peroxide and bleach are chemical properties. In order of volatility: alcohol<water<motor oil