LG1: STUDY OF MATTER
Matter is anything that has mass and occupies space.
Physical change is reversible (ice to water, nothing new is formed),
chemical isn’t (burning something, something new is formed)
Molecule can be 2+ atoms/compounds bonded together
Mixture is combo of 2/+ pure substances.
An allotrope is a different form of a molecule (like diamond and graphite)
LOOK AT ANALYTICAL LAB TECHNIQUES!
Chromatography, distillation and fractional distillation and all that
The more affinity something has for the stationary phase, the closer to the
bottom its going to be.
You get physical and chemical properties. Physical properties (colour,
density etc) can be discovered without changing the chemical
composition. Chemical properties need the thing to undergo a change in
chemical composition. You get 2 types of properties, namely intensive and
extensive.
Intensive properties Does not depend on the amount of substance
present. E.g. temp and melting pt.
Extensive properties Depends on the quantity of substance present.
E.g. mass and volume.
Molecular formula gives actual numbers and types of atoms in molecule.
Used to represent molecular structure (CO2, CH4, that kinda stuff)
Empirical formula gives the relative no. + types of atoms in a molecule.
Subscripts in an empirical formula are always smallest possible whole no.
ratio. (CO2, HO instead of H2O2)
An amorphous solid is a solid in which there is no long-range order of the
positions of the atoms. Examples are like polystyrene or candy floss
The smallest repeating building block in a crystal is a unit cell.
The three-dimensional stacking of unit cells is the crystal lattice.
Molecular solids are composed of molecules held together by weak IMFs.
Cuz these forces are weaker than covalent bonds, these solids are soft
and are often gases/liquids at room temp due to low BP and MP. Most are
, non-conducting when pure. Examples are sulphur, ice, sucrose, solid CO2
etc.
Covalent network solids consist of atoms held together in large
networks/chains with covalent bonds. These have extremely high boiling
pts and harddd (diamond, graphite, quartz)
All homogenous mixtures are solutions
The atomic number is the number of protons in the nucleus of an atom of
an element. Each element has a unique number of protons. For example,
an atom with 47 protons is always a silver atom and has an atomic
number of 47. The atomic number is used to distinguish different
elements from one another.
The mass number is the sum of the number of protons and neutrons in
the nucleus of an atom of an element. Atoms that have the same atomic
number but different mass numbers are called isotopes. For example, all
atoms with atomic number 6 are carbon atoms, but carbon atoms with
mass numbers of 12 and 13 are isotopes of one another.
Matter is anything that has mass and occupies space.
Physical change is reversible (ice to water, nothing new is formed),
chemical isn’t (burning something, something new is formed)
Molecule can be 2+ atoms/compounds bonded together
Mixture is combo of 2/+ pure substances.
An allotrope is a different form of a molecule (like diamond and graphite)
LOOK AT ANALYTICAL LAB TECHNIQUES!
Chromatography, distillation and fractional distillation and all that
The more affinity something has for the stationary phase, the closer to the
bottom its going to be.
You get physical and chemical properties. Physical properties (colour,
density etc) can be discovered without changing the chemical
composition. Chemical properties need the thing to undergo a change in
chemical composition. You get 2 types of properties, namely intensive and
extensive.
Intensive properties Does not depend on the amount of substance
present. E.g. temp and melting pt.
Extensive properties Depends on the quantity of substance present.
E.g. mass and volume.
Molecular formula gives actual numbers and types of atoms in molecule.
Used to represent molecular structure (CO2, CH4, that kinda stuff)
Empirical formula gives the relative no. + types of atoms in a molecule.
Subscripts in an empirical formula are always smallest possible whole no.
ratio. (CO2, HO instead of H2O2)
An amorphous solid is a solid in which there is no long-range order of the
positions of the atoms. Examples are like polystyrene or candy floss
The smallest repeating building block in a crystal is a unit cell.
The three-dimensional stacking of unit cells is the crystal lattice.
Molecular solids are composed of molecules held together by weak IMFs.
Cuz these forces are weaker than covalent bonds, these solids are soft
and are often gases/liquids at room temp due to low BP and MP. Most are
, non-conducting when pure. Examples are sulphur, ice, sucrose, solid CO2
etc.
Covalent network solids consist of atoms held together in large
networks/chains with covalent bonds. These have extremely high boiling
pts and harddd (diamond, graphite, quartz)
All homogenous mixtures are solutions
The atomic number is the number of protons in the nucleus of an atom of
an element. Each element has a unique number of protons. For example,
an atom with 47 protons is always a silver atom and has an atomic
number of 47. The atomic number is used to distinguish different
elements from one another.
The mass number is the sum of the number of protons and neutrons in
the nucleus of an atom of an element. Atoms that have the same atomic
number but different mass numbers are called isotopes. For example, all
atoms with atomic number 6 are carbon atoms, but carbon atoms with
mass numbers of 12 and 13 are isotopes of one another.
