Unit Two Notes Behavior of Matter

Transcription

1 Unit Two Notes Behavior of Matter Matter can be described by its PHYSICAL PROPERTIES Characteristics of matter that can be observed or measured without changing its chemical identity. Qualitative Properties: Colour, flavour, odour, look (shine, texture, sparkle), malleability, state Quantitative Properties: Melting temp., boiling temp., hardness, viscosity (flow rate), mass, volume, density Matter is anything that has mass and takes up space. Mass is the amount of matter in an object/sample. o Measured in kilogram (kg), gram (g), milligram (mg) Volume is the amount of space a substance takes up. o Solids are measured in cubic metres (m 3 ), cubic centimetres (cm 3 ) o Liquids are measured in litres (L), millilitres (ml) o 1 cubic cm = 1 ml Density the amount of mass in a certain volume of a material o Less densely packed particles will float on more densely packed particles. o Measured in g/ml (usually) o The density of water is about 1g/mL o Use the density equation to calculate: Density = mass volume 1

2 Matter can be described by its CHEMCAL PROPERTIES The ability of matter to react with another substance to form one or more new substances. Combustibility: the ability of a material to catch on fire and burn in air. Reactivity: with oxygen, with acids Lack of reactivity Matter can be described based on PHYSICAL and CHEMICAL CHANGES Physical Changes A change in matter that does not alter its chemical identity or composition o Shape o state The Four States of Matter (look at page 135 to fill in chart) STATE COMMON CHARACTERISTICS EXAMPLES 2

3 Chemical Changes a change in matter that produces a new substance o reactants: substances that take part in the chemical change o products: substances that are formed The Law of Conservation of Mass Mass of reactants = mass of products Mass is neither created nor destroyed during a chemical reaction it is conserved. Matter can be classified based on Physical and Chemical Changes Mixtures can be separated into parts by physical changes Pure substances: Compounds o Can be broken down into 2 or more elements by chemical changes but NOT physical changes Elements o Can t be broken down by physical OR chemical changes 3

4 Model vs Theory Model: a verbal, mathematical or visual representation of a scientific structure or process help visualize a process that cannot be seen with the unaided eye Theory: o an explanation that has been supported by consistent and repeated experimental results, being accepted by most scientists The Particle Model of Matter a model that enables people to visualize and understand the structure of matter. (draw diagram from page 138) 4

5 The Kinetic Molecular Theory Kinetic energy is energy in motion! Key Points of the Kinetic Molecular Theory include (see page 137) a. b. c. 3. a. b. c. 4. 5

6 Changes of State Draw from page 139. Include the definitions to the side of your drawing. 6

7 Diffusion: The movement of one material through another Example: smell in a room Thermal Expansion and Contraction When you add energy to a material you increase the kinetic energy of the particles. One way to add energy is to add heat. Thermal expansion is When a heat is added to a substance the particles move faster and further apart. This causes the substance to expand and the volume will increase. Thermal contraction is When heat is taken away the particles slow down and move closer together. 7

8 The Atom An ATOM is the smallest particle of an element that retains the properties of that element. o An atom is made up of subatomic particles: o Electrons negatively charged sub atomic particles that are found surrounding the nucleus o Protons positively charged particles that are found in the nucleus. They determine the charge of the nucleus and identity of the atom indicated on the periodic table of elements. o Neutrons a particle with no charge found in the nucleus Draw Figure 2.31 from page 162 in your text book. Electric Charge o Two types: positive (protons) and negative (electrons) o Positive charge of protons attracts the negative charge of the surrounding electrons o Nuclear force acts within the nucleus to hold protons together o Atoms have an equal number of protons and electrons making the atom uncharged or neutral 8

9 Quarks and Leptons QUARKS Protons and neutrons are made up of smaller elementary particles that cannot be split apart called Quarks. Protons are known as composite particles because the quarks are held together by gluons act as glue to bind then together. There are six different flavours of quarks classified based on their properties, including mass and electric charge: up, down, strange, charm, top and bottom LEPTONS Electrons are themselves elementary particles called leptons. They also come in six different flavours: Electron, muon, tau, electron neutrinos, muon neutrinos and tau neutrinos The key difference between quarks and leptons is that quarks experience the strong force, but leptons do not. 9