year 10 eoy exam Flashcards
describe solids in terms of the arrangement, movement, and energy of the particles
they are arranged in regular rows and columns, and they are very tightly packed together, they have very little energy and do not move very much (vibrate)
describe liquids in terms of the arrangement, movement, and energy of the particles
they are arranged randomly, and are still touching with some spaces between them. they have more energy than solids and the particles can move around and over each other
describe gasses in terms of the arrangement, movement, and energy of the particles
they have a lot of energy, and are randomly and widely spaced out. they can move freely
what is the name of the change from solid to liquid?
melting
what is the name for the change from a liquid to a gas?
evaporation
what is the name of the change from gas to solid?
deposition
what is the name of the change from a solid to a gas?
sublimation
what is the name of the change from a liquid to a solid?
freezing
what is the name for the change from a gas to a liquid?
condensation
what is a solvent?
the liquid in which a substance is going to be dissolved
what is a solute?
the substance that is going to be dissolved
what is a solution?
it is the mixture of a solvent and dissolved solute
what is a saturated solution?
a solution where no more solute can be dissolved
what is the definition of an element?
a substance containing only one type of atom
what is the definition of a compound?
a substance containing more than one type of atom chemically bonded together
what is the definition of a mixture?
two or more substances that are not chemically bonded
what is simple distillation?
it is a method to separate a a solvent from a solution
the solution is heated, and the solvent evaporates, and moves away and is then cooled
simple distillation works because the solvent will have a lower boiling point than the solute
how can you figure out if a substance is pure or not?
if it has a fixed boiling point, it is pure
mixtures may melt/boil over a range of temperatures
what is fractional distillation?
it is used to separation of a mixture of liquids by their boiling points
it works when the liquids have different boiling points
the liquids are vaporised and are put in the fractionating column, where they then condense at different heights/temperatures, so they can be easily separated into fractions
what is filtration?
it separates an insoluble salt (precipitation) from the salt solution
you would filter out the precipitate from the solution using filter paper
what is crystallisation?
it is used to separate a soluble salt from the solution
you heat the solution in an open container to let the solvent evaporate out, then leave it to cool. then the solid would begin to come out of the solution and crystallise.
what is an atom?
the smallest/simplest part of an element
what is a molecule?
two or more atoms that are chemically bonded
what is the nucleus of an atom made up of?
protons and neutrons
where are the electrons in an atom?
they are in the electron shells
what is the relative charge of sub-atomic particles?
proton: +1
neutron: 0
electron: -1
what is the relative mass of the sub-atomic particles
neutron: 1
proton: 1
electron: 1/2000
what is the atomic number?
the number of protons (the bottom one)
what is the mass number?
the number of protons and neutrons added together (the top one)
what is the number of electrons equal to?
the number of protons/the atomic number
what is an isotope?
atoms with the same number of protons (therefore the same element) but a different number of neutrons
how do you calculate the relative atomic mass from abundances?
eg. atom 1 has y neutrons 60% abundance
atom 2 has n neutrons, 40% abundance
(y x 60) + (n x 40)
/
100
how are atoms ordered in the periodic table?
by atomic number
what does the group an element is in mean?
the number of outer electrons
what does the period an element is in mean?
the number of electron shells
an atom, y has 8 electrons, what group and period is it in, and what electric configuration would it have?
group 6, period 2
2, 6
are metals able to conduct electricity?
yes
can non-metals conduct electricity?
no
what kind of oxides do metals have?
basic oxides
what kind of oxides do non-metals have?
acidic or neutral oxides
why do elements in the same group have similar chemical properties?
they have the same number of outer electrons so they will react and bond similarly
why do noble gases not react easily?
because they have a full outer shell so they are stable and don’t need to gain or loose any electrons
how do you calculate the relative formula mass (Mr) from the relative atomic mass (Ar)?
add the Ar of each of the elements and multiply each Ar by how many atoms of it are needed
eg. H2O= (Hx2) + (Ox1)
= (1x2) + (16x1)
= 2 + 16
= 18
so the Mr of water is 18
what is the unit for the amount of a substance?
mol
what is the relationship between mass, relative formula mass, number of moles?
mass = Mr x moles
how do you calculate percentage yield?
amount that you got divided by the total amount you could have gotten multiplied by 100
what is meant by the term empirical formula?
the simplest whole-number ratio between atoms/ions in a compound
what is meant by the term molecular formula?
the actual number of each type of element in a molecule
describe the method to find out the formula of a metal oxide by combustion
- measure the mass of the empty crucible and lid
- add a sample of magnesium into the crucible and measure the mass of it (with the lid)
- work out the mass of the magnesium by subtracting the mass of the empty crucible from the mass of the crucible and the magnesium
- put the crucible and magnesium on a tripod and gauze over a Bunsen burner and heat on a blue flame for several minutes
- make sure to lift the lid of the crucible while you heat it every 30 seconds/frequently to make sure the magnesium is fully oxidised
- after several minutes, weigh the crucible, and then heat for another minute and weigh again. if the mass has stayed the same, the magnesium has been fully oxidised, if not, continue weighing and heating until the mass stays constant
- measure the mass of the crucible and it’s contents. subtract the mass of the empty crucible from it to find the mass of the metal oxide formed
why must the lid be on when heating magnesium, to form magnesium oxide to find the formula?
to prevent the magnesium escaping, but the lid must be lifted frequently to let oxygen in to react with magnesium
how do you find the formula of magnesium oxide from the practical of combusting metal oxides to find the formula
find the number of moles of magnesium and oxygen:
say the mass of Mg is x and the Mr is 24, x/24=a
say the mass of O is y and the Mr is 16, y/16=b
so the ratio is a:b, Mg(a)O(b)
how are ions formed?
by electron loss or gain
what is the charge of metals in group 1?
+1 (because they loose one electron so it gets less negative/more positive)
what is the charge of metals in group 2?
+2 (because they loose 2 electrons so it gets less negative/more positive)
what is the charge of metals in group 3?
+3 (because they loose 3` electrons so it gets less negative/more positive)
what is the charge of non-metals in group 5?
-3 (because they gain 3 electrons so they get more negative/less positive)
what is the charge of non-metals in group 6?
-2 (because they gain 2 electrons so they get more negative/less positive)
what is the charge of non-metals in group 7?
-1 (because they gain 1 electrons so they get more negative/less positive)
what is the charge of Ag (silver)?
+1
what is the charge of Cu (copper)?
+2
what is the charge of Fe (iron)?
+2 or +3
what is the charge of Pb (lead)?
+2
what is the charge of Zn (zinc)?
+2
what is the charge of hydrogen?
+1
what is the charge of hydroxide?
-1
what is the charge of ammonium?
+1
what is the charge of carbonate?
-2
what is the charge of nitrate?
-1
what is the charge of sulphate?
-2
what is the formula of hydroxide?
OH-1
what is the formula of ammonium?
NH4+1
what is the formula of carbonate?
CO₃-2
what is the formula for nitrate?
NO₃-1
what is the formula for sulphate?
SO4-2
what is the charge of ammonia?
nothing, it is not an ion and therefore has no charge
what is the formula for ammonia?
NH3
what is an ionic bond in terms of electrostatic bond?
strong electrostatic attraction between positive and negative ions
why do compounds with giant ionic lattices have high melting points?
the strong electrostatic attraction requires a lot of energy to overcome
can ionic compounds conduct electricity as a solid, and why?
no, because the ions are not free to move
can ionic compounds conduct electricity when aqueous or molten, and why?
yes, because the ions are free to move
what is a covalent bond?
strong electrostatic attraction between a pair of shared electrons and the positive nuclei
why do simple covalent structures have low melting/boiling points?
because the weak intermolecular forces require little energy to overcome
why does the melting/boiling point of simple molecular forces increase with increasing relative molecular mass (generally)?
because the bigger the molecule, the stronger the intermolecular forces
describe how you would represent metallic lattices with a 2d diagram
when metal atoms join together, the outer electrons become delocalised
metals have a giant regular arrangement of layers of positive ions surrounded by a sea of delocalised electrons
what is metallic bonding?
the strong electrostatic attraction between positive metal ions and delocalised electrons
what are the typical physical properties of metals?
they are good conductors of heat and electricity
they are malleable
they have a high melting point
what is the trend in physical properties in group 1 metals?
they get lighter and softer, get dull more quickly (going down the group)
what happens when lithium reacts with water?
fizzing, moves about, gas produced