Science Test

Pure substances

Made up of only one kind of particle and have a fixed or constant structure.

Elements

A chemical substance that cannot be broken down into other substances by chemical reactions.

Compounds

A substance made from two or more different elements that have been chemically joined.

Atoms

The basic particles of the chemical elements.

Molecules

Two or more atoms bonded together.

Ions

An atom or group of atoms that has an electric charge.

Heterogeneous mixture

A mixture where you can see lumps of each component.

Homogeneous mixture

A mixture where the individual components are not visible.

Physical properties

Methods of description such as length.

Chemical properties

Methods of description such as flammability.

Physical change

A change where the shape or look changes.

Chemical change

A change where the substance itself changes.

Separation techniques

Methods such as distillation, filtration, evaporation, and decanting.

Solutions

Ionic compounds are made due to ionic bonding, while molecular compounds are made due to covalent bonding.

Diatomic elements

Elements that exist as two-atom molecules, including H, N, O, F, Cl, Br, and I.

Factors affecting solubility

Temperature, pressure, polarity, and molecular size.

Unsaturated solution

A solution that can dissolve more solute.

Saturated solution

A solution that cannot dissolve more solute.

Supersaturated solution

A solution that has more solute dissolved than it is supposed to.

Atomic notation

Includes mass number, symbol, and atomic number.

Protons

Located in the nucleus, with a mass of 1 and a charge of +1.

Electrons

Located outside the nucleus, with a mass of 0 and a charge of -1.

Neutrons

Located in the nucleus, with a mass of 1 and a charge of 0.

Phases of matter

Solid (fixed shape, not compressible), liquid (takes shape of container, not compressible), gas (takes shape of container, compressible).

Aqueous

A term indicating a substance has been dissolved in water.

Precision

Measures how close results are to one another.

Accuracy

Measures how close results are to the true or known value.

Calculating density

Density is calculated as mass divided by volume.

Scientific notation

A way to express numbers, e.g., 0.000073 = 7.3 times 10 to the -5.