Question | Answer |
Rounding | The procedure of dropping nonsignificant digits in a calculation result and adjusting the last digit reported. |
Scientific Notation | The representation of a number in the form A x 10^n, where A is a number with a single nonzero digit to the left of the decimal point and n is an integer, or whole number. |
Accuracy | The closeness of a single measurement to its true value. |
Chemical Property | A characteristic of a material involving its chemical change. |
Compound | A substance composed of two or more elements chemically combined. |
Element | A substance that cannot be decomposed by any chemical reaction into simpler substances. |
Experiment | An observation of natural phenomena carried out in a controlled manner so that the results can be duplicated and rational conclusions obtained. |
Gas | The form of matter that is an easily compressible fluid. |
Heterogeneous Mixture | A mixture that consists of physically distinct parts, each with different properties. |
Hypothesis | A tentative explanation of some regularity of nature. |
Law of Conservation of Mass | The total mass remains constant during a chemical change (chemical reaction). |
Liquid | The form of matter that is a relatively incompressible fluid. |
Mass | The quantity of matter in a material. |
Matter | Whatever occupies space and can be perceived by our senses. |
Mixture | A material that can be separated by physical means into two or more substances. |
Physical Change | A change in the form of matter but not in its chemical identity. |
Physical Property | A characteristic that can be observed for a material without changing its chemical identity. |
Solid | The form of matter characterized by rigidity. |
Theory | A tested explanation of basic natural phenomena. |
Unit | A fixed standard of measurement. |
Significant Figures | Those digits in a measured number (or in the result of a calculation with measured numbers) that include all certain digits plus a final digit having some uncertainty. |
Number of Significant Figures | The number of digits reported for the value of a measured or calculated quantity, indicating the precision of the value. |
Exact Number | A number that arises when you count items or sometimes when you define a unit. |
Substance | A kind of matter that cannot be separated into other kinds of matter by any physical process. |
States of Matter | The three forms that matter can commonly assume - solid, liquid, and gas. |
Precision | The closeness of the set of values obtained from identical measurements of a quantity. |
Phase | One of several different homogeneous materials present in the portion of matter under study. |
Law of Definite Proportions (Law of Constant Composition) | A pure compound, whatever its source, always contains definite or constant proportions of the elements by mass. |
Law | A concise statement or mathematical equation about a fundamental relationship or regularity of nature. |
Homogeneous Mixture (Solution) | A mixture that is uniform in its properties throughout given samples. |
Chemical Change (Chemical Reaction) | A change in which one or more kinds of matter are transformed into a new kind of matter or several new kinds of matter. |