EOY Flashcards
Advantages of nanoparticles in suncream?
better coverage
more protection from the sun’s UV rays
Disadvantages of nanoparticles in suncream?
may cause potential cell damage to the body
could have harmful effects on the environment
Order of sizes
dm, cm , mm , um (micrometre), nm
Pure substance
a single element or single compound
What is the test for chlorine gas?
a damp litmus paper turns white
oxides of nitrogen cause
acid rain
particulate matter causes
global dimming
what is the relative mass of an electron?
very small
what is the relative mass of a proton and neutron?
1
Why are instrumental methods used to measure gas?
accurate
Compounds formed from only non-metals consist of particles called?
molecules
Compounds formed when non-metals react with metals consist of particles called?
ions
The relative formula mass of a substance, in grams, is one … of the substance
mole
Why did Mendeleev leave gaps?
for undiscovered elements
State two similarities between hydrogen and atoms in group 1?
they have 1 electron in their outer shell
forms ions with a 1+ charge
Describe how knowledge of the numbers of protons and electrons in atoms allow chemists to place elements in their correct order and correct group.
number of electrons = number of protons
chemical properties depend on the outer electrons
number of shells gives the period
There are no transition elements between the Group 2 element magnesium and the Group 3 element aluminium.
Give a reason why, in terms of electronic structure.
2nd shell can only have a maximum of 8 electrons
Suggest what predictions Mendeleev was able to make about these undiscovered elements.
predicted their properties
predicted that they were metals
Why is lithium less reactive than potassium, in terms of electronic structure?
outer shells are closer to the nucleus
stronger force of attraction between the outermost electron and the nucleus, less easily lost in reaction
State why transition metal oxides are added to pottery glazes
For colour
State two properties which coinage metals should have
hard - so they don’t get scratched
unreactive - so they don’t corrode
Explain 2 differences in the reactions of potassium and lithium with water
potassium
produces a lilac flame
melts and forms a ball
Give 3 properties of why alkali metals should be grouped together
they form ions with 1+ charge
they are very reactive
they react with water to form alkaline solutions
How did Mendeleev improve John Newland’s periodic table and why?
he left gaps for undiscovered elements
so that the elements would fit into their proper groups
alcohol + …. —> carbon dioxide + water
oxygen
What is the functional group in an alcohol molecule?
OH-
How do alkene molecules form a molecule of plastic?
double bond breaks
and the alkenes join together
Not all molecules are compounds but …
all compounds are molecules
Suggest 2 of the main costs of making a plastic from crude oil
energy is required
cost of crude oil
Suggest two problems caused by the disposal of plastics in landfill sites
landfill sites are filling up
not biodegradable
Plastics made from plants would be more environmentally friendly than plastics made from
crude oil, why?
Biodegradable
renewable resources
Suggest a problem caused by plastics going to landfill sites.
there is not enough space in landfill sites
How are resources saved by recycling more plastics
less crude oil is used
Suggest why recycling, products made from C2H4 and C3H6 is difficult
two different polymers
Why might repeats be conducted?
to improve accuracy
to calculate an average
to identify anomalous results
Suggest why the student warmed the liquid hydrocarbon using warm water and not a
Bunsen flame.
it is flammable
Crude oil is a …. of different substances
mixture
Why should sulfur be removed from petrol?
sulfur produces sulfur dioxide
which cause acid rain
What is metallic bonding?
is the electrostatic attraction between metal ions and a sea of ‘delocalised’ electrons
Suggest how the use of a suspension of limestone decreases one of the environmental
impacts that the waste gases would cause
Sulfur dioxide and oxides of nitrogen both cause acid rain. They can be neutralised by calcium carbonate.
Difference between a smart polymer and a regular polymer
a smart polymer can return to its original shape when conditions change
Why is incomplete combustion of methane dangerous?
carbon monoxide is made
which combines with the haemoglobin and prevents oxygen from being carried in the blood
Explain why, in terms of the energy involved in bond breaking and bond making, the combustion of methane is exothermic.
energy is required to break bonds
energy is released when bonds are made
more energy is released than energy taken in
Why can graphine rub off?
layers have weak intermolecular forces
so they can slide over each other
A nanodiamond contains a few … atoms
hundred
What is made from chlorine?
bleach
carbon particles cause
global dimming
How is carbon dioxide removed from the atmosphere?
plants / trees absorb carbon dioxide
coal ‘locks up’ carbon dioxide
How to measure volume of gas produced?
The reaction mixture is connected to a gas syringe where gas is collected
rate of reaction =
volume of gas produced / time taken
Rate if resction is measured in
cm3/s
How to measure change in mass?
Reaction is placed on a mass balance
As reaction proceeds, mass of the flask decreases as gas is given off
Rate of reaction for gas is
g/s
Explain how metals can conduct electricity (4 marks)
Metals are giant lattices
that are made up of positive ions
with delocalised electrons
so electrons can move through the metal
Describe how the structure of an alloy is different from the structure of a pure metal.
An alloy has different sizes of atoms
Alloys have distorted layers
Why is nitinol used in dental braces?
can return to its original shape
Explain why chlorine (Cl2) is a gas at room temperature, but sodium chloride (NaCl) is a solid at room temperature.
Chlorine - covalent bonds between atoms - forming simple molecules - so there is weak attraction between molecules - therefore has a low boiling point Sodium Chloride - ionic bonds - therefore strong bonds in all directions - between oppositely charged atoms - forming a giant lattice - so high boiling point
