Chemistry LT 1.1 & 1.2 Study Guide

Matter

Anything that has mass and takes up space (volume).

Pure Substance

Matter with a fixed composition and consistent properties.

Element

A pure substance made of only one type of atom.

Compound

A pure substance containing two or more different elements chemically bonded.

Mixture

Two or more substances physically combined, not chemically bonded.

Homogeneous Mixture

A mixture that is uniform and looks the same throughout.

Heterogeneous Mixture

A mixture that is not uniform; different parts are visible.

Classification of Gold (Au)

Element

Classification of Water (H₂O)

Compound

Classification of Salt Water

Homogeneous mixture

Classification of Salad

Heterogeneous mixture

Physical Property

A characteristic observable or measurable without changing substance identity.

Chemical Property

Describes a substance's ability to undergo a chemical change.

Physical Change

A change altering form or appearance without forming a new substance.

Chemical Change

A change that forms one or more new substances.

5 Signs of Chemical Change

Gas produced, temperature change, precipitate formed, color change, light produced.

Difference: Property vs. Change

Property describes ability; change is the active process occurring.

Flammability vs. Burning

Flammability is a chemical property; burning is a chemical change.

Accuracy

How close a measurement is to the true or accepted value.

Precision

How close repeated measurements are to each other.

Dartboard Analogy for Precision

Darts grouped closely together (regardless of bullseye distance).

Mass vs. Weight

Mass is amount of matter; weight is gravitational force on mass.

Meniscus

The curved upper surface of a liquid; read at bottom at eye level.

Digit Estimation Rule

Record all certain digits plus one estimated digit.

Accuracy vs. Precision practice: 9.9g, 10.0g, 10.1g (Target: 10.0g)

Both accurate and precise.

Accuracy vs. Precision practice: 15.1g, 15.2g, 15.1g (Target: 10.0g)

Precise, but not accurate.