AP Chemistry - Chapter 1: Chemical Foundations [Vocabulary]

scientific method

A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

measurement

a quantity that has both a number and a unit

hypothesis

A testable prediction, often implied by a theory

theory

A hypothesis that has been tested with a significant amount of data

model

A pattern, plan, representation, or description designed to show the structure or workings of an object, system, or concept

natural law

a generalized rule to explain a body of observations in the form of a verbal or mathematical statement

law of conservation of mass

Matter is not created nor destroyed in any chemical or physical change

SI system

International System of units based on the metric system and units derived from the metric system

mass

the amount of matter in an object

weight

A measure of the force of gravity on an object

uncertainty

an estimate of how much a measured or calculated value differs from a true value

significant figures

All the digits that can be known precisely in a measurement, plus a last estimated digit

accuracy

A description of how close a measurement is to the true value of the quantity measured.

precision

a measure of how close a series of measurements are to one another

random error

error that has equal probability of being too high or too low

systematic error

Error that shifts all measurements in a standardized way. Decreases accuracy. Can result in bias

exponential notation

A way to write a number using a base and an exponent.

unit factor method

an equivalence statement between units used for converting from one unit to another

dimensional analysis

a technique of problem-solving that uses the units that are part of a measurement to help solve the problem

density

mass/volume

matter

Anything that has mass and takes up space

states (of matter)

the physical forms of matter, which include solid, liquid, and gas

homogeneous mixture

a mixture that is uniform in composition; components are evenly distributed and not easily distinguished

heterogeneous mixture

A mixture that is not uniform in composition; components are not evenly distributed throughout the mixture

solution

A homogeneous mixture of two or more substances

pure substance

A sample of matter, either a single element or a single compound, that has definite chemical and physical properties

physical change

A change in a substance that does not involve a change in the identity of the substance

distillation

A process that separates the substances in a solution based on their boiling points

filtration

A process that separates materials based on the size of their particles.

chromatography

A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material.

paper chromatography

method of separating a mixture of different colours. The liquid soaks through the paper and carries the mixture with it. Some substances are carried faster than others so the substances are separated along the paper

compound

A substance made up of atoms of two or more different elements joined by chemical bonds

chemical change

A change in matter that produces one or more new substances

element

A pure substance made of only one kind of atom