eoy exams yr 9 Flashcards
what is the definition of a solvent?
liquid that dissolves the solid
what is the definition of soluble?
can be dissolved (in the solvent)
what is the definition of saturated?
no more solid will dissolve
what is the definition of a solute?
the solid that will be dissolved in a solvent
what is the definition of a solution?
the mixture of a solvent and a solute
what is the definition of insoluble?
cannot be dissolved
what is the definition of suspension
solid spread out in a solution
what is solubility usually measured in?
g per 100g (of water/other solvent)
how would you separate dissolved salt and water?
through evaporation or crystalisation
how would you separate a mixture of inks?
chromatography
how would you separate ethanol and water?
distillation
how would you separate sand and water?
filtration
what is the chemical test for water?
anhydrous copper sulphate (white —> blue) hydrous copper sulphate
what is the physical test for pure water?
boiling/melting point
explain the energy and movement of:
- a solid
- a liquid
- a gas
solid: low energy + vibrating
liquid: medium energy + more movement than a solid, atoms can slide over each other
gas: high energy + can move freely
what is the name of the process of a solid –> liquid?
melting
what is the name of the process of a liquid –> gas
evaporation
what is the name of the process of a gas –> liquid
condensing
what is the name of the process of a liquid –> solid
freezing
what is the name of the process of a solid –> gas
sublimation
what is the name of the process of a gas –> solid
deposition/desublimation
if you put ammonia and hydrogen chloride in a tube, why does the ammonium chloride (white powder) form closer to the hydrogen chloride
the hydrogen chloride is heavier so it diffuses slower
what is the definition of an atom?
an atom is the smallest part of a chemical element that can exist
what is the definition of a molecule?
two or more atoms that are chemically bound together
what is the relative mass of neutrons, protons, and electrons?
neutrons - 1
protons - 1
electrons - 1/2000
what is the relative charge of neutrons, protons, and electrons
neutron: 0
proton: +1
electron: -1
what is the definition of an isotope?
atoms with the same number of protons (therefore the same element) but a different number of neutrons
how would you calculate the relative atomic mass if the atoms were:
Cl^35 - 75.8%
Cl^37 - 24.2%
(both have 17 atomic number)
[(35 x 75.8) + (37.24.2)] /100
= 3548.4/100
=35.5 (3sf)
how are element arranged in the periodic table?
ascending atomic number
what does the group the element is in tell you about the atomic structure of it?
number of electrons on the outer shell
what does the period the element is in tell you about the atomic structure of it?
the number of electron shells
why are noble gasses unreactive?
they are already stable, do not need to loose/gain any electrons
what is the definition of an ionic bond?
ionic bond is the strong electrostatic attraction between positive and negative ions
what is the definition of oxidation (in terms of electrons)?
loss of eletrons
what is the definition of reduction (in terms of electrons)?
gain of electrons
what structure do ionic compounds form?
giant ionic lattices
why do ionic compounds have high melting points?
the strong electrostatic attraction requires a lot of energy to break/overcome
why are ionic compounds not conductive as a solid, but are as molten/aqueous
solid - ions cant move
aqueous/molten - ions are free to move and carry charges
definition of an element?
a substance of only 1 type of atom
definition of a compound?
two or more different elements chemically bonded
definition of a mixture?
two or more substances not chemically bonded
what are the characteristics of metals?
- good conductors
- high melting point
- malleable
- can be made to be shiny
composition of air (+%’s)
nitrogen - 78%
oxygen - 21%
argon - 0.9%
carbon dioxide - 0.035 or 0.04
what is the test for oxygen?
the glowing splint method - place a ‘glowing’ splint into the gas, if it relights, oxygen is present
what happens when carbon is combusted in oxygen
orange sparks - slightly acidic
what happens when iron is combusted in oxygen
orange flame
what happens when magnesium combusts with oxygen?
bright white light - white solid formed
very slightly alkaline
what happens when sulphur is combusted with oxygen
blue flame
thermal decomposition of a metal carbonate
meta carbonate –> metal oxide + carbon dioxide
copper (III) carbonate –> ______ + ______
copper oxide + carbon dioxide
what is the chemical test for carbon dioxide?
limewater (clear –> cloudy)
what colours does methyl orange go in acids, alkaline, and neutral substances
acid - red
neutral - yellow
alkaline - yellow
what colours does phenolphthalein go in acids, neutral, and alkaline substances
acids - colourless
neutral - colourless
alkaline - pink
what colours does blue litmus go in acids, neutral, and alkaline substances
acids - red
neutral - blue (stay the same)
alkaline - blue (stay the same)
what colours does red litmus go in acids, neutral, and alkaline substances
acids - red (stays the same)
neutral - red (stays the same)
alkaline - blue (stay the same
what are the pH’s for strong acids, weak aids, neutral, weak alkalis, strong alkalis
strong acid: 0-3
weak acid: 4-6
neutral: 7
weak alkaline: 8-10
strong alkaline: 11-14
what is the reaction between metals and acids
metal + acid –> salt + hydrogen
properties of ionic compounds
- high melting point
- hard
- not conductive as a solid; conductive as a liquid/aqueous/molten
- brittle
- usually soluble in water
- usually not soluble in other solvents
what is the test for hydrogen?
squeaky pop test - place a lit splint into the gas, if hydrogen is present it will make a pop
definition of an acid
proton donor (H+)
definition of a base
proton acceptor (h+)
definition of an alkali
OH- donors (bases that are soluble in water)
describe a test for making soluble salts (using insoluble base + acid)
- heat the acid until bubbles start to appear
- slowly add the base until no more disappears, all the acid has reacted
- filter out the excess base
- pour the filtrate into an evaporating basin
- heat until crystals begin to form
- leave to crystallise for a few days
- pick out crystals
- dry with filter paper
acid + base –> ____ + ____
water + salt
what is the equation for metal carbonates reacting with acids
acid + metal carbonate —> salt + water + carbon dioxide
what happens to the metal carbonate in acids
disappears
how do you know carbon dioxide is released in a metal carbonate + acid reaction?
it fizzes
what is precipitation?
an insoluble solid being produced in a solution
what do metals form
giant metallic lattice
definition of metallic bonding
strong electrostatic attraction between positive metal ions and delocalised eletrons
describe the reactivity of group 1 metals with water
lithium: fizzes, moves about, produces gas
sodium: turns into a sphere, releases heat, fizzes and moves more than lithium - more reactive than lithium
potassium: burns with a lilac flame, reacts quicker than sodium - more reactive with sodium
rubidium: explodes as soon as it touches the water - more reactive than potassium
caesium: breaks the tub of water due to the explosion - more reactive than rubidium
how do the reactions of group 1 metals and air change?
as you go down the periods, the metal turns dull quicker (reacts faster)
why does the reactivity of group 1 metals increase as you go down the periods?
the lower the period, the more electron shells it has, so the last electron is further away from the nucleus - so the attraction is weaker and the electron is more easily lost
definition of redox reaction
a reaction where reduction and oxidation occurs
definition of reducing agent
gets oxidised - they give the electrons to the substance being reduced
what is an ore
a rock containing a metal
how do you extract mercury or silver
dont need to be extracted - maybe purified
how do you extract something less reactive than carbon?
displacement using carbon
how do you extract something more reactive than carbon?
electrolysis - breaking down a compound using eectricity
what are the uses of aluminium?
cables, planes, and pots and pans
what are the uses of copper?
electrical pipes, pots and pans, water pipes
what are the uses of high carbon steel
cutting tools, masonry nails
what are the uses of low carbon steel
nails, car bodies, ships
what are the uses of stainless steel
kitchen sinks, saucepans, knives and forks
what are alloys
mixture of a metal and one or more elements
what is rust
iron –> iron (III) oxide —> hydrated iron (III) oxide
how do barrier methods prevent rust
stops oxygen and water from reaching the iron
has to be replaced
how do sacrificial methods prevent rust
add a more reactive metal to the iron - that metal will react instead
has to be replaced + expensive
galvanising method for preventing rust
zinc coating -> is a barrier and will react before iron
