Introduction to Chemistry Quiz

Study Notes

There are two ways to classify matter: by its physical state and by its chemical constitution.

Element: Cannot be broken down into simpler substances by chemical reactions. Examples: Na, H, O
Compound: Composed of two or more elements chemically bonded. Examples: H2O, H2, O2, NaCl
- Compounds have properties different from their constituent elements.
- Compounds have constant proportions of elements by mass, known as the Law of Constant Composition.
Mixture: Can be separated into two or more substances by physical methods.
- Mixtures have variable composition and do not follow the Law of Constant Composition.
- Heterogeneous mixture: Has physically distinct parts with different properties. Example: A mixture of iron filings and copper
- Homogeneous mixture (solution): Uniform throughout with consistent properties. Example: Salt dissolved in water

Chemical change: Forms a new substance with a different composition. Example: Water decomposing into hydrogen and oxygen gas.
Physical change: Alters the form of a substance without changing its composition. Example: Water changing from solid (ice) to liquid.

The total mass remains constant during a chemical change (reaction). In other words, mass is neither created nor destroyed.

Celsius (°C):
- 100 °C boiling point of water
- 0 °C melting point of ice
Fahrenheit (°F):
- 212 °F boiling point of water
- 32 °F melting point of ice
Kelvin (K):
- 373.15 K boiling point of water
- 273.15 K melting point of ice
Conversion formulas:
- °F = (°C x 1.8) + 32
- °C = (5/9) (°F - 32)
- K = °C + 273.15
- °C = K - 273.15