Unit 1 Measurement & Chemistry Review

Vocabulary flashcards covering key concepts from Unit 1: physical vs chemical properties and changes, matter types, density, measurement, lab techniques, and SI units.

Physical property

A characteristic that can be observed without changing the identity

Physical change

A change in which the substance’s form or state changes but its chemical composition remains the same.

Chemical change

A process that results in a new substance with different chemical composition.

Matter

Anything that has mass and occupies space.

Mixture

A combination of two or more substances that can be separated by physical means; may be homogeneous or heterogeneous.

Homogeneous mixture

A mixture with uniform composition throughout; the components are evenly distributed.

Heterogeneous mixture

A mixture with non-uniform composition; components are visibly different.

Pure substance

A substance with a fixed composition; either an element or a compound.

Element

A substance that cannot be broken down into simpler substances by chemical means.

Compound

A substance composed of two or more elements chemically bound in fixed ratios.

Solid

A state of matter with definite shape and volume; particles are closely packed and vibrate slowly.

Liquid

A state of matter with definite volume but indefinite shape; particles flow and are less tightly packed than in a solid.

Gas

A state of matter with neither definite shape nor definite volume; particles are far apart and move rapidly.

Density

mass/volume (g/cm³ or mls)

Mass

The amount of matter in an object, typically measured in grams or kilograms.

Volume

The amount of space an object occupies; for solids in cm³, for liquids in mL.

Displacement method

A technique to measure the volume of an irregular object by observing the change in water level in a graduated cylinder.

Direct vs. inverse relationship (in context of density and size)

Density is independent of the object's size (not affected by how big the object is).

Percent error

A measure of accuracy: Percent error = |experimental − accepted| ÷ accepted × 100%.

Percent yield

accepted/experimental x 100%

Celsius to Kelvin

K = C + 273.15.

Kelvin to Celsius

C = K − 273.15.

SI units

International System of Units; base units include meter, kilogram, second, kelvin, ampere, mole, candela.

milli

100

centi

100

kilo

1/1000

Reading a graduated cylinder

Read the measurement at the bottom of the meniscus at eye level for accuracy.

Most accurate graduated cylinder size

Smaller cylinders (e.g., 10 mL) have finer markings and typically higher accuracy than larger ones.

Accuracy vs. precision

Accuracy is closeness to the true value; precision is reproducibility/consistency of measurements.

Displacement-based density

Density can be found by mass divided by the difference between final and initial water volumes (ρ = m/(Vf − Vi)).

Volume of a rectangular solid

Volume = length × width × height.

Matter examples (from notes)

Carbon dioxide (compound), gold (element), granite rock (mixture), water (compound), sugar in water (solution), cream (mixture), Cu (element), O₂ (element), NaCl (compound).