Chemistry Chapter 1: Mixtures vs. Pure Substances

Questions and Answers

They have a definite chemical composition.

They have no definite chemical composition. (correct)

They always have the same properties.

They consist of only one type of particle.

Solid (correct)

Liquid

Gas

Plasma

Reactivity

Melting point (correct)

Chemical composition

Burning point

Universally accepted measurement standards. Signup and view all the answers

Metre Signup and view all the answers

Gram Signup and view all the answers

By undergoing a change in composition. Signup and view all the answers

FPS Signup and view all the answers

Distilled water Signup and view all the answers

Quantitative measurement Signup and view all the answers

Study Notes

Mixtures lack a definite chemical composition and show varying properties, while pure substances have a fixed composition and consistent properties.
Examples of mixtures include paint and concrete, contrasting with pure substances like pure metal and distilled water.

Solids feature tightly held particles in a structured arrangement, providing definite shape and volume.
Liquids consist of closely packed particles that can move, resulting in a definite volume but no fixed shape.
Gases have particles dispersed widely, with increased freedom of movement compared to solids and liquids.
Change in state (solid, liquid, gas) can occur through alterations in temperature and pressure.

Physical properties are observable without altering the substance's identity, including color, odor, melting point, boiling point, and density.
Chemical properties involve changes in the substance's composition, such as combustion reactions producing new substances.

Measurement compares a property of matter against a stable, reproducible standard.
Quantitative properties like mass, length, area, volume, and time can be measured using numbers and specific units.
Example: A classroom's length may be noted as 10 m, indicating both quantity and unit measurement.

Units are standardized, universally accepted measures used to quantify properties of matter.
Common examples of units include the meter (m) for length and kilogram (kg) for mass.

Units can be represented in various systems, such as:
- CGS (centimeter, gram, second)
- FPS (foot, pound, second)
- MKS (meter, kilogram, second)

The International System of Units (SI) was introduced in 1960 as a revised metric system.
The seven fundamental SI units are:
- Length: Meter (m)
- Mass: Kilogram (kg)
- Time: Second (s)
- Temperature: Kelvin (K)
- Amount of substance: Mole (mol)
- Electric current: Ampere (A)
- Luminous intensity: Candela (cd)
Derived units for other measurements (e.g., speed, volume, density) can be formulated from these fundamental SI units.