Core + Paper 1 Flashcards
what is an element?
a substance made from atoms that have the same number of protons in the nucleus
what is an atom?
the smallest particle of an element that still has its chemical properties
what is a molecule?
a molecule consists of 2 or more of the same atoms that are chemically bonded together
what is a compound?
a compound consists of two or more different elements chemically joined together
what is an ion?
an ion is an electrically charged particle
How is an Ion formed?
an ion is formed when an atom or group of atoms loses or gains electrons
who were the 5 scientist that helped discover the structure of the atom
Dalton
Thomson
Rutherford
Borh
Chadwick
what did Dalton think the atom was
dalton thought that the atom was the smallest think and could not be broken into anything smaller
what was Thompsons discover
Thompson created the plum pudding model where the atom was a sphere of positive with negative electrons dotted around
what did Rutherford discover and what was his model
Rutherfurd discovered the nucleus(gold foil experiment) and it was a solar system model where there was a positively charged nucleus surrounded by negative electrons in orbit
what did Bohr discover about the atom?
that the electrons were laid out in shells/ energy levels
what did Chadwick discover
neutrons
what does the (aq) state symbol mean
in solution
are metal atoms more likely to lose or gain electrons?
lose electrons
what is the relative mass of an electron?
1/1836
what is an isotope?
An atom with the same number of protons but different amounts of protons
who developed the modern periodic table?
Mendeleev
how did Mendeleev order the periodic table?
order of atomic mass
What pair of elements did Mendeleev swap
tellurium and iodine
what were the horizontal rows on the periodic table called?
periods
what are periods
the number of shells that an atom has
what were the vertical columns called?
groups
what did the groups show
The number of electrons on the last shell
what side are the metals on the periodic table
the left side
what do you call a positively charged ion?
cation
what do you call a negatively charged ion
anion
how does the name of a non-metal element change when it becomes a negative ion
add -ide to end
How does the name of a negatively charged ion change when it becomes a negative ion that also contains oxygen
add -ate to the end
what are ionic bonds?
strong electromagnetic forces of attraction between oppositely charged ions
what do you call the structure formed in an ionic compund
lattice
do ionic compounds have high or low melting/boiling points?
high melting point
why do ionic compounds have high melting and boiling points?
because there are many strong ionic bonds and a large amount of energy must be transferred to the lattice structure to break these bonds
do ionic compounds dissolve in water?
yes
state why sodium chloride does not conduct electricity in a solid state
the charged particles are not free to move around and carry a current
what is a covalent bond?
a bond formed when a pair of electrons are shared between 2 atoms
give 3 properties of covalent bonds
- are strong
- formed between non-metal atoms
- often produce molecules which can be compounds or elements
how do we model covalent bonds
dot and cross diagrams
what are simple molecular substances in terms of their bonding
consist of just a few atoms joined together by strong molecular bonds
why do simple molecular substances have low boiling/melting points?
even though there are strong covalent bonds, the molecules are joined together by weak intermolecular forces that are broken during state changes
what state are simple molecular substances in at room temp
liquid or gas
do simple molecular substances conduct electricity?
no, because their molecules are not electrically charged and there are no electrons that are free to move
name a simple molecular substance that dissolves in water
chlorine, carbon dioxide, sulfur dioxide
what are giant covalent bonds in terms of their bonding
they consist of many atoms, that are joined by strong covalent bonds and are arranged in a regular lattice structure
why do giant covalent bonds have a high boiling temperature?
it is because of how a lot of energy must be transferred to break the many strong covalent bonds during melting and boiling.
give 2 examples of giant molecular substances
Diamond and Graphite
why does graphite conduct electricity but diamond doesn’t
this is because carbon has the ability to form 4 covalent bonds. but in graphite, carbon only forms 3 which means that there is a delocalised electron that is free to move around and carry the current
what are some other forms of carbon?
graphene’s and fullerenes
what is the structure of graphene?
graphene is a giant molecular substance that resembles a single layer of carbon. each atom is connected to three other atoms.
what are the 3 properties of graphene?
- graphene conducts electricity because of delocalised electron
- graphene is very strong and flexible due to its strong covalent bonds
- graphene is almost transparent because it is only one atom thick
what are the 2 types of fullerenes?
buckyballs and nanotubes
give 3 properties of buckyballs
-have delocalised electrons so they can conduct electrons
-the carbon atoms are arranged in pentagons and hexagons
-they are soft when in the solid state because they have weak intermolecular forces
give 3 properties of nanotubes
-have closed ends or open ends
-can conduct electricity because they have delocalised electron
-are very strong because the structure has many strong covalent bonds
how does the appearance vary on metals to non-metals
metals are shiny
while non-metals are dull
how do electrical and conduction vary on metals and non-metals
metals can conduct electricity and are good conductors of heat
while some non-metals are also good conductors but cannot conduct electrical
how do density and meting points compare on non-metals and metals?
metals have high melting points and density while
non-metals have low melting points and have a low density
what is the opposite of malleable
brittle
describe the structure and bondings of metal
- made up of a large lattice of positively charged metal ions and surrounded by a sea of delocalised electrons
- metallic bonds are strong electrostatic forces of attraction between positive metal ions and delocalised electrons
why are metals malleable?
layers of ions have the ability to slide over each other and change the shape of the metal without shattering
what does ductile mean
the ability to be stretched into a thin wire without shattering
what are the five models that can be used to represent atom structure?
- written formulae
- drawn structures
- ball-and-stick diagrams
- space-filling models
- Dot and cross diagrams
what are the empirical formulae?
the simplest whole number ratio of atoms of each element
what is the symbol for relative atomic mass?
Mr
write down the 6 steps to calculating the empirical formula using grams
- write down the symbol of each element as a header
- write down the mass of each element (given)
- write down the atomic mass of each element
- for each element calculate mass / atomic mass
- divide each answer by the smallest answer.
- then multiply the numbers to remove fractions and write down the empirical formulae
what is the conservation of mass?
the total mass of reactants and products stays constant during a chemical reaction. The total mass before and after a reaction is the same.
what is a closed system?
a closed system is a situation where no substance can enter or leave during a reaction
what is the stoichiometry of a reaction?
it has to do with the ratio of the amounts of reactants and products involved when you balance a chemical equation you are finding the stoichiometric equation
what is a solution?
a solution is a mixture of a solute in a solvent
what is the solvent?
the solvent is the substance that the solute dissolves in
what is the solute?
the solute is the substance that dissolves
what does dm3 stand for
cubic decimetres
what do you need to calculate the concentration of a solution?
the mass of the solute in grams and the volume of the solution in cubic decimetre
how many cm cubes is a dm
1000cm3
what is the unit of measurement for concentration?
dm-3
what is a mole
a mole is the unit for the amount of a substance
what is Avagadro’s constant?
6.02 * 10^23
what is the mass of 1 mole of carbon?
12g
what is the formula for moles?
amount(mol) = mass(g)/Mr
what is the arrangement of particles like in solids?
close together, regular pattern
what is the arrangement of particles like in liquids?
close together, random
what is the arrangement of particles like in gases?
far apart, random
what is the movement of particles like in solids?
vibrate around a fixed position
what is the movement of particles like in liquids?
move around each other
what is the movement of particles like in gases?
fast in all direction
order the different states of matter. from which has the least stored energy to the most
solids - least
liquid
gasses - most
what do call gas to liquid?
condensing
what do call liquid to solid?
freezing
what do you call solid to liquid?
melting
what do call liquid to gas?
boiling./evaporating
what do you call gas to solid?
deposition
what do you can solid to gas?
sublimation
what is an element?
it is a substance that consists only of atoms with the same atomic number
what is a compound?
a compound is a substance that consists of two or more different atoms(different elements) that are chemically joined together
what 2 structures can elements exist as
atoms or molecules
what is a pure substance?
a substance that only contains one element or compound
what is a mixture?
a substance that contains different elements and/or compounds that are not chemically joined together
what is the difference between impure and pure substances based on their melting point?
pure substances will have a sharp melting point while impure substances will not because it has many different impurities that will each have different melting points
what is fractional distillation used for
to separate liquids from a mixture of miscible liquids
what is simple distillation used for?
to separate a solvent from a solution
explain simple distillation
simple distillation works because the solute will have a higher boiling point than the solvent. so when the solution is heated the solvent will boil, pass into the condenser, cool and collect in the other container while the solute is left.
explain fractional distillation
fractional distillation works because the liquids that need to be separated will all have different boiling points. so by heating the mixture up:
- the mixture boils
- hot vapour rises up the column
- vapour condenses when it hits the cool surfaces of the column it condenses and drips back down
- the fraction with the lowest boiling point will reach the top of the column first
- its vapour will then pass into the condenser where it is cooled and transferred into a different container
- if you carry on heating, the vapours from the fractions with higher boiling points pass into the condenser
what do you use filtration for
you use filtration to separate an insoluble substance from a liquid or a solution.
what do you call the material left in the filter after filtration
residue
what do you call the solution created from filtration
filtrate
what do you produce with crystallisation?
solid crystals
what are the 3 steps to crystallisation?
- the solution is heated to remove enough solvent to make the solution saturated
- as the solution cools crystals will form
- The crystals are then separated from the liquid and dried
why do we use a water bath in crystallisation?
to give you more precise control over the temperature
why does filtration work?
because the filter paper has tiny pores that are large enough to let dissolved substances through while also being small enough to stop insoluble solid particles going through
why does crystallisation work
This is because the solubility of a solvent is higher the higher the temperature. so when a saturated solution cools down the excess solute forms crystals.
what is paper chromatography used for
to separate the mixture of soluble substances
explain the process of setting up chromatography
- put spots of the samples you want to separate onto the paper and label them with a pencil.
- put the paper into liquid, but make sure it does not reach the level of the inks.
- as the water moves up the sheet of paper the water will dissolve the samples.