Science quiz 2 atoms and physical and chemical change.

• Chemical properties refer to how elements react with other substances.
• The boiling point is the temperature at which a liquid turns into gas.
• Physical properties can be observed and measured without changing the identity or composition of a substance.
• Melting point is the temperature at which a solid turns into a liquid.
• Density refers to the mass per unit volume of an object or substance.
• JJ Thomas created the blueberry muffin or raisin bun model
• John Dalton stated that atoms can not be created, destroyed or broken into smaller pieces.
• Dalton also said all atoms of the same element are identicle in mass in size
• Compounds are created when atoms of different elements link together
• Rutherford found the nucleus in an atom
• Bohr found that electrons move around the nucleus in specific energy levels or shells
• Atoms have a positively charged nucleus and a negatively charged electron orbiting it.
• The number of protons determines what type of atom it is (atomic number)
• Chemistry is the study of matter
• Matter is anything with mass or volume
• Mass is measured by grams or kilograms
• All matter is either a pure substance or a mixture
• Volume is the amount of space an object takes up
• Volume is measured in L or mL
• Pure substances only contain one type of particle
• The particles in a pure substance are chemically bonded
• Elements are pure substances that cannot be anything more simple
• Mixtures are made up of combinations of pure substances
• It is easy to break up a mixture into its pure substances
• Heterogeneous mixtures are when the substances are easily visible
• Homogeneous mixtures are when it looks the same and its evenly distributed
• Physical Properties: Conductivity, melting point, boiling point, solubility, state (liquid, solid, gas), density
• You can observe, measure and calculate (quantitative properties) these physical properties.
• Physical properties are change in appearance but no new substances are formed
• Chemical properties change into a new substance and describes the behavior
• Greek philosophers thought that the smallest pieces of matter were made up of atomos.
• Aristotle believed matter was made out of earth, air, fire and water
• Alchemist experimented with matter, their activities marked the beginning of our understanding of matter.
• While determining chemical properties consider if the substances will react to each other.
• While determining chemical properties consider the rate of the reactions (fast, slow)
• While determining chemical properties consider if any heat is produced or removed from the reaction.
• While determining chemical properties consider what proportions are needing to produce a product.
• Quantitative physical properties describes the heaviness or matter
• Quantitative physical properties are calculated by mass and volume
• Qualitative properties of physical properties are colour, malleability (object bending), and hardness