Unit 2: Matter Flashcards
Matter and states of matter
- Anything that has mass and volume.
- Solid, liquid, gas.
Physical and chemical properties. Give examples.
- Are observed without changing composition. “same substance”
Colour, volume, physical state, density, melting and boiling point. - Are observed during changes in composition. “different substance”.
Burning, rusting.
Element
- Consists of only one kind of element.
- Can’t be broken down into simpler matter.
Pure substance
Matter whose composition (identity, arrangement, and ratio of chemical elements) will not change under any condition.
Molecule. Give an example.
An independent structural unit of 2+ atoms chemically bound together.
E.g. Oxygen occurs in air as diatomic molecules.
Compound
2+ different elements chemically bound together.
Mass fraction and mass percent. Formula.
- Mass of compound due to mass of element.
- Mass of element in compound divided by mass of compound (x100).
Heterogenou mixture
Visible boundaries between the components, composition not fixed.
Homogenous mixture (solution)
No visible boundaries between components, composition is uniform (looks the same).
Law of mass conservation
Total mass of substances doesn’t change during chemical reaction.
Law of multiple proportions
Whenever elements A and B form more than one compound, the different masses of B combine with a fixed mass of A are in a ratio of small whole numbers.
Law of constant (definite) compostition
Compounds will always consist of the elements in the same ratio by mass
Atomic number (Z)
- Number of protons (p+) an atom’s nucleus.
- Unique to each element.
Mass number (A)
- Number of protons (p+) and neutrons (n0) in an atom’s nucleus.
