CHEMISTRY C1 and C2 Flashcards
What is a compound?
2 or more elements chemically bonded together
(sugar, water, salt).
What is a mixture?
2 or more elements or compounds that are not bonded together
(sand and water).
Fractional distillation
a mixture of several substances, is distilled and the evaporated components are collected as they condense at different temperatures.
Simple Distillation
separating out a liquid from a solid.
What is Mobil Phase?
when molecules can move.
Stationary phase
when molecules can’t move.
Rf Value = ?
Distance travelled by the substance / distance travelled
by the solvent.
What is an isotope?
Atoms of the same element but different mass numbers.
Difference between solute and soluble?
soluble is something that dissolves in water and solute doesn’t dissolve in water.
What happens when you get further down the periodic table?
it gets more reactive.
Where are protons neutrons and electrons found?
proton = centre
neutron = centre
electron = outer shells
Alkali metal properties
good conductor of heat and electricity, react with oxygen (so are placed in oil), shine when cut open briefly, soft to cut, low melting and boiling points.
Free marks for alkali metals
More shells.
More shielding.
less nuclear attraction.
easier to lose outer electron.
Ionic bonding
Electrostatic attraction between a metal cation and non-metal anion in a lattice.
Metal + Oxygen–> metal oxide which performs an ionic bond to create rust.
How do metals become positive ions
lose electrons.
How do non-metals become negative ions
gain electrons.
Cation?
ion with positive charge (metal).
Anion?
ion with negative charge (non-metal).
Covalent bonding?
Covalent bonding is when electrons are shared that happen between non-metals only and doesn’t involve ions.
Properties of large covalent substances
Carbon can bond to itself 4 times and keeps growing by 4.
Covalent bonds are very strong.
intermolecular bonds are very weak.
Graphite is very soft because of it being intermolecular which acts like lubricant.
Diamond is very hard as it has a covalent bond and attaches 2 four other carbon atoms.
Why are Nanotubes the future?
Nanotubes are made of Graphene (which can conduct electricity).
fullerings can be used for for drugs by delivering them to certain parts of the body.
Can be used for many things while barely adding any weight.
Pure metal vs alloy
ALLOY:
DISTORTED LAYERS.
MIXTURE OF METALS
LAYERS CAN’T SLIDE EASILY
MUCH HARDER
PURE METAL:
ONE TYPE OF ATOM
REGULAR LAYERS
LAYERS CAN SLIDE EASILY
MALLEABLE (SOFT)
Mass of compound
H₂SO₄ = 98
12 (from H₂) = 2
32 (from S) = 34+
164 (from O₄) = 98
2+32+64
Moles
A mole is a unit of substance, one mole of a substance is the relative formula mass of that substance in grams
Equation =
M/ MrMole
Mass = Relative formula massMole
Rfm = 39
19/39=0.4871794872
