| A | B |
|---|
| Matter | anything that has mass and takes up space |
| Atoms | smallest part of an element; basic building block of all substances |
| Pure substance | elements and compounds that have a specific set of identifying properties |
| Elements | atoms of the same kind that cannot be broken down further by physical or chemical means; a pure substance |
| Compounds | substances made of two or more elements chemically combines; a pure substance |
| Mixtures | any substances made up of a combination of two or more elements or compounds in which each substance keeps its own properties |
| Physical properties | characteristics of matter that can be measured and observed without changing the makeup of the substance |
| Density | the measure of an object’s mass compared to volume; heaviness compared to size/volume |
| Boiling point | temperature at which a substance changes from a liquid to a gas; a physical property |
| Melting point | temperature at which a substance changes from a solid to a liquid; a physical property |
| Luster | the physical property of shininess or the way a substance reflects light; a dull luster means that the substance is not shiny |
| Malleable | a physical property of metals that allows them to be hammered into different shapes |
| Ductile | a physical property of metals that allows them to be drawn out into a wire |
| Brittle | a physical property that allows substances to break or shatter easily |
| Conductivity | a physical property of substances that allows heat or electricity to move easily through them |
| Periodic table | chart of all known elements arranged in rows (periods) by ascending atomic number and columns by family groups |
| Element families | also called groups; are columns of elements on the periodic table that have many similar properties; they are usually numbered 1-18 |
| Metals | one of the large classifications of elements generally located on the left side of the periodic table – to the left of the zigzag line |
| Nonmetals | one of the large classification of elements generally located on the right side of the periodic table – to the right of the zigzag line |
| Chemical symbol | a one or two letter representation of an element |
| Chemical formula | represents a compound; contains element symbols and the ratio of atoms |
| pH | a measure of how acidic or basic a solution is – its concentration; measured on a scale of 1-14 |
| Acids | chemicals with a pH lower than 7; sour tasting (if a food), corrosive compounds that react with metals |
| Bases | chemicals with a pH higher than 7; bitter-tasting, usually solid substances that feel slippery when dissolved in water |
| Neutral | neither acid nor base; a pH of 7; pure water is neutral |
| Indicator | a substance used to determine pH; e.g. litmus paper, pH paper, phenolphthalein |
| Chemical equation | contains chemical formulas and other symbols used to represent a chemical reaction that has occurred |
| Chemical reaction | any change that alters the chemical properties of a substance or forms a new substance |
| Reactants | substances that take part in a chemical reaction |
| Products | new substances formed in a chemical reaction |
| Yields | to become; symbol between the reactants and products in a chemical equation |
| Law of Conservation of Matter | a law which states that mass/matter cannot be created or destroyed; in a chemical reaction, the total mass of the reactants equals the total mass of the products |
| Balanced equation | supports Law of Conservation of Matter by showing that the type and number of reactant atoms is equal to those in the product(s) |
| Coefficient | a whole number placed in front of a symbol or formula in a chemical equation to show the number of atoms or molecules involved as reactants or products |
| Chemical properties | properties that can only be observed when there is a change in the composition of a substance |
| Burning | a chemical process that takes place when a substance reacts with oxygen quickly and releases heat and light energy |
| Rusting | a chemical process that takes place when a substance reacts with oxygen and water slowly |
| Physical change | change in which the appearance or state of matter changes but the substance’s properties and makeup remain the same |
| Chemical change | a change in which one or more substances combine or break apart to form new substances |
| Precipitate | tiny particles of solid in a liquid, made by a chemical reaction |
