Paper 1 (2022) (wrongs) Flashcards
What section of the periodic table does not conduct electricity and is dull?
Right side ( noble gases)
Two differences in physical properties which transition metals and group 1 Metals
Group 1 is softer, less dense, lower melting points, less strong than transition metals
What happens when magnesium and oxygen react
Magnesium loses electrons, oxygen gains electrons
two electrons are transferred, MAGNESIUM IONS AND OXIDE IONS ARE FORMED
Why does diamond have a very high melting point
covalent bonds are strong and many covalent bonds have to be broken which requires a lot of energy
why are fullerenes good to transport drugs in body
They are hollow
Unreactive
Not toxic
Large surface area to volume ratio
Calculate the number of C70 molecules that can be made from one mole of carbon atoms. The Avogadro constant = 6.02 × 10 23 per mole
(moles of C70 molecules = 1/70)
1/70 x 6.02x10^23
=8.6x10^21
Why is excess zinc oxide used rather than excess hydrochloric acid?
Zinc oxide can be filtered off
Name one other compound that the student could add to hydrochloric acid to produce zinc chloride.
Zinc Oxide
Zinc Hydroxide
Zinc carbonate
Describe how the student should obtain crystals of zinc chloride from a solution of zinc chloride.
Heat the solution until crystallisation point is reached
leave the solution to cool/crystallise
Rubidium and potassium are added to water. Predict one observation you would see that shows that rubidium is more reactive than potassium.
more vigorous bubbling, bigger flame
general formula for alkali and water
Alkali + Water –> Alkali hydroxide + hydrogen
A mesh is used to keep the products of the electrolysis apart. Suggest one reason why the products of the electrolysis must be kept apart.
so products don’t react
Why is oxygen described as being reduced in the reaction between sodium and oxygen?
Oxygen gains electrons so is being reduced
OILRIG
inwhat state do metals conduct
in solids and liquids
what side of the periodic table are electrical insulators
all non metals and covalent structures
what is the difference between electrolysis and chemical cells
electrolysis uses electricity to produce a chemical reaction
chemical cells use chemical reactions to produce electricity
what is formed at the positive and negative electrode for Copper nitrate
Positive = Oxygen
Negative = Copper
what is formed at the positive and negative electrode for Potassium Iodide
Positive = Iodine
Negative = Hydrogen
Some of the copper produced did not stick to the negative electrode but fell to the bottom of the beaker. Suggest how the students could find the total mass of copper produced.
filter the mixture wash and dry the copper / residue weigh the copper collected add to the increase in mass of the electrode
Copper nitrate solution is blue. Suggest why the blue colour of the copper nitrate solution fades during the electrolysis.
copper ions are discharged from the solution
physical properties of most transition metals?
- they are good conductors of heat and electricity
- they can be hammered or bent into shape easily
- they have high melting points (but mercury is a liquid at room temperature)
- they are usually hard and tough
- they have high densities
why does copper not react with hydrochloric acid
copper is below hydrogen in the reactivity series so can’t displace the hydrogen therefore can’t react
The gas produced at the positive electrode was oxygen. The oxygen was produced from hydroxide ions. Name the substance in the solution that provides the hydroxide ions.
water
Describe how the solid forms at the negative electrode in terms of copper
copper ions gain two electrons to
give me the electrolysis rule
CATHODE - If the metal element is more reactive than hydrogen, then HYDROGEN will be produced, if not then the METAL is produced
ANODE - if halide is present, the HALOGEN is formed, if not, hydroxide ions are discharged and OXYGEN IS FORMED
what does the atomic number show
how many protons are in the element
disadvantage of rechargeable batteries
they contain toxic chemicals which are harmful when disposed of
they don’t last as long
they take a long time to recharge
Give two limitations of this simple particle model for hydrogen gas.
Shows particles as solid spheres
It is only 2-D
does not show the movement of the particles / speed
Why is it not correct to say that the boiling point of a single bromine molecule is 59 °C?
boiling point is a bulk property
boiling point is linked to the intermolecular forces so cannot only be one molecule
why does the reaction of halogens have to be done in a fume cupboard
halogens are toxic
to prevent inhalation of the gas
which is greater, the number of atoms in 3 moles of sulfur or the number of molecules in 2 moles or iron sulfide
the number or atoms in 3 moles of sulfur is greater than the number of molecules in 2 moles of iron sulfide because theres the same number of atoms in one mole of sulfur as there is in 1 mole of iron sulfide so in 3 moles of sulfer there will be more atoms than there are molecules in 2 moles of iron silfide
State the trend in boiling points of halogens down group 7 and explain why this is the case.
The atoms increase in size, as they gain extra electron shells, and the intermolecular forces become stronger. More energy is required
Define metallic bonding
A lattice of positively charged ions in a sea of delocalised electrons
give structure and properties in graphite and diamond with bonding
diamond
- each carbon atom is joined to four other carbon atoms by strong covalent bonds, the carbon atoms form a regular tetrahedral network structure
- strong bonds makes diamond very hard, high melting point and does not conduct electricity
Graphite
- each carbon atom is joined to 3 other carbon atoms. the carbon atoms form layers of hexagonal rings there are no covalent bonds between the layers. there is one non-bonded - or delocalised electron from each atom
- so can conduct electricity. forces between layers are weak so slide over each other makes graphite slippery so good for lubricants
There are different ways of extracting metals from their ores. Aluminium is extracted by electrolysis while iron is extracted by reduction with Carbon. Explain why these two metals are extracted in different ways.
Metals more reactive than carbon, such as aluminium, are extracted by electrolysis, while metals less reactive than carbon, such as iron, may be extracted by reduction with carbon.
Describe how a student could use insoluble oxide and an acid to produce soluble copper sulphate crystals.
1) Add 50 cm3 dilute acid into a beaker and warm gently using a Bunsen burner
2) Add the copper(II) oxide slowly to the hot dilute acid and stir until the base is in excess (i.e. until the base stops dissolving and a suspension of the base forms in the acid)
3) Filter the mixture into an evaporating basin to remove the excess base
4) Gently heat the solution in a water bath or with an electric heater to evaporate the water and to make the solution saturated
Check the solution is saturated by dipping a cold glass rod into the solution and seeing if crystals form on the end
5) Leave the filtrate in a warm place to dry and crystallise
Decant excess solution and allow the crystals to dry
what is a strong acid
A strong acid is any acid that ionizes completely in solutions.
Explain the difference between random errors and systematic errors.
systematic errors is when there is something wrong with the measuring equipment but random errors are when something happens because of unpredictable events
when a reaction is exothermic, does the bond energy increase
In an exothermic reaction, the bonds in the product have lower bond energy (weaker bonds) than the reactants.decrease in bond energy
Describe the difference between rechargeable and non-rechargeable batteries.
rechargeable battery is capable of reversing the chemical reaction by forcing a current in the opposite direction.
Alkaline batteries are non-rechargeable
Discuss advantages and disadvantages of hydrogen fuel cells
pro
- only releases water vapour (not harmful)
- Fuel economy equivalent to about twice that of gasoline vehicles.
- hydrogen is abundant and can be made with renewable energy source
cons
- Expensive to produce and requires energy for the production process.
Describe how a sulphuric acid of an unknown concentration could be titrated with sodium hydroxide to determine this unknown concentration. Include all relevant terminology and methods that should be used to maximise precision.
1) measure 25cm3 of Sulphuric acid using a measuring cylinder and place on a white tile
2) add the indicator methyl orange (drop) to the sodium hydroxide
3) fill the burette with the sodium hydroxide and place the tip of the burette slightly in the conical flask
4) by adding one drop at a time, drop the sodium hydroxide and swirl
5) keep doing until you see a sudden colour change. it will go from red to yellow
6) record the volume by reading at eye level at the meniscus
7) repeat until have two concordant results
Sodium is in Group 1 of the modern periodic table. Describe what you would see when sodium reacts with chlorine
White solid formed
Flame
Colour of chlorine disappears
Some suncreams contain zinc oxide as nanoparticles or as fine particles. Suggest one reason why it costs less to use nanoparticles rather than fine particles in suncreams.
- less can be used (for the same effect)
- greater surface area (to volume ratio)
Give one limitation of using a dot and cross diagram to represent an ammonia molecule
- it is only 2D
Explain why ammonia has a low boiling point. You should refer to structure and bonding in your answer.
It has small molecules so weak intermolecular forces which are easy to overcome
Explain why a mixture of cyolite is used as the electrolyte instead of using only aluminium oxide.
mixture has a lower melting point (than aluminium oxide) (so) less energy needed
Explain why the positive electrode must be continually replaced.
This oxygen reacts with the carbon of the positive electrodes, forming carbon dioxide, so they gradually burn away
Sodium metal and chlorine gas are produced by the electrolysis of molten sodium chloride. Explain why sodium chloride solution cannot be used as the electrolyte to produce sodium metal.
because hydrogen gas would be produced not sodium because sodium is more reactive than hydrogen
Explain why the excess hydrogen must be burned off.
to prevent hydrogen being released into the atmosphere because it would be explosive
at which electrode does oxidation take place and where is reduction
Oxidation = positive anode
Reduction = negative cathode (where positive ions gain electrons)
describe what happens to the positive ions in electrolysis
positive ions move to the negative cathode and gain electrons to form atoms
(reduction)
describe what happens to the negative ions in electrolysis
negative ions move to the positive anode and lose electrons to for atoms (oxidation)
chemical properties of transition metals
- they are less reactive than alkali metals such as sodium
- they form coloured ions of different charges
- some are very unreactive (silver and gold)
- many are used as catalysts
