Chem Final Exam: big pack Flashcards
What are the 3 states of matter? (most energy, to least energy)
-Gas
-Liquid
-Solid
Solid:
-regular arrangement
-fixed positions
-vibrating on the spot
-touching/very close
Liquid:
-random arrangement
-moving around
-close together/touching
Gas:
-particles have the most energy (move the fastest)
-particles are the most spread apart
-random arrangment
Interconversions between three states of matter:
Gas -> Liquid: condensation
Liquid -> Solid: freezing (all 3 deposition)
Solid -> Liquid: melting
Liquid -> Gas: evaporation (all 3 sublimation)
What is deposition?
particles lose kinetic energy, move less and become more regualrly arranged and close together
What is sublimation?
particles gain more energy, move around more and become more randomly arranged and further apart
Dilution of coloured solutions and diffusion of gases:
-movement of particles from an area of high concentration to an area of low
-doesn’t occur in solids, since the particles are fixed together
-coloured solutions are diluted by adding water, because the particles of the colour diffuse to the air of low concentration, mixing it with the water molecules, causing dilution to occur
Solvent:
liquid in which the solute is being dissolved
Solute:
substance that dissolves in a liquid to form a solution
Solution:
mixture formed when a solute has dissolved in a solvent
Saturated solution:
solution in which no more solvent can be dissolved
Element:
substance made from only one type of atom
Compound:
2 or more atoms chemically bonded together
Mixture:
-2 or more particles mix together
What are pure substances?
-> made from only 1 type of atom
-they melt and boil at specific temperatures
Simple distillation: (l->s)
-used to separate out liquids from solutions
-solution is heated, the part of the solutions that has lowest boiling point evaporates
-vapour then cools, condenses and is collected
Fractional distillation: (m->l)
-used to seperate mixtures of liquids
-liquid with the l.b.p evaporated first, when temp of thermomter matches b.p of liquid, it will reach the top of the column
-liquid with h.b.p might also evaporate, but column is cooler towards the top
Filtration: (i,s -> l)
-used to seperate an insoluble solid from a liquid
-liquid part runs through the paper, leaving behind the solid residue
Crystillisation: (s,s -> s)
-separates a soluble solid from a solution
-some water evaporates and the solution gets more concentrated
-the salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution
Paper Chromatography: (m)
-used to separate mixtures and give information to help identify them
-the more soluble a substance is, the further up the paper it travels
Equation for the Rf value: (chromatography)
Rf = distance travelled by solute/distance travelled by solvent
Atom:
smallest piece of an element that can exist
-all substances are made of atoms
Molecule:
formed when atoms join together by chemical bonds
Proton: subatomic particle (r.m, r.c, p)
relative mass: 1
relative charge: +1
position: in the nucleus
Neutron: subatomic particle (r.m, r.c, p)
relative mass: 1
relative charge: 0
position: in the nucleus
Electron: subatomic particle (r.m, r.c, p)
relative mass: 0.0005
relative charge: -1
position: in shells around the nucleus
Atomic (proton) number:
-tells you how many protons there are
number of electrons = number of protons
Mass (nucleon) number:
-number of protons + number of neutrons
-to get n. of neutrons, just subtract the atomic number from the mass number
Isotopes:
different atoms of the same element containing the same number of protons but different numbers of neutrons
eg:
Carbon-12: 6 protons, electrons, neutrons
Carbon-13: 6 protons, electrons and 7 neutrons
Relative atomic mass (of an element):
-average mass (relative abundance) of all isotopes in an element
-A.R = (% of isotope A x mass of isotope A) + (% of isotopw B x mass of isotope B) /100
Metals
elements that react to form positive ions
Non-metals:
elements that react to form negative ions
Group number:
gives number of electrons in outer shell e.g. group 3 has 3 electrons in their outer shell
Period number:
gives number of electron shells e.g. period 1 has 1 shell of electrons
Noble gases: Group 0
-They have 8 electrons in their outer shell (except helium, that has 2)
-they are unreactive and do not easily form molecules, because they have a stabble arrangement of electrons