Mocks Part 1. Flashcards
Gie one type of subsatnce that can react with acids to form a soluble salt.
Metals.
Give the formula of calcium nitrate.
Ca(NO3)2
Describe a method to make pure crystals.
You need to have magnesium oxide and sulfuric acid
• add sulfuric acid to evaporating dish and slowly heat
• add magnesium oxide
• Stir the mixture so they are combined.
• continue adding until magnesium oxide is excessive
using a filter paper and funnel filter the solution
• heat solution in an evaporating basin • to crystallisation point when visibile crystals begin to form
• remove the dish from the heat and leave to crystallise • pat dry with filter paper or use a drying oven or a dessicator.
Determine the formula of iron pyrites.
FeS2
Give two differences of iron and soduim.
- iron forms coloured compounds
* iron can be a catalyst
Explain why carbon can be used to extract nickel from nickel oxide?
Carbon is more reactive than nickel so it displaces it which means it can be used to extract nickel.
Why do alkaline batteries eventually stop working?
the electrolyte is used up.
Why can alkaline batteries not be recharged?
Because they are alkaine.
What is the overall reaction in a hydrogen fuel cell?
2H2 + O2 → 2H2O
Compare a lithium ion with a hydrogen fuel cell?
Hydrogen fuel cells may be seen as better than lithium ions because they do not need to be recharged and no pollutants are made. However the lithium ion may be better because lithium ions use energy more efficiently so they save money as the cost of recharging is much less than refuelling hydrogen. But lithium ions release toxic chemicals when discarding it wheras hydrogen makes no pollutants. After all of the advantages considered i think the lithium ion batteries are better because hydrogen takes up alot of space and is dificult to store and it also made of fossil fuels so it will run and lithium ions produce no emmsions.
Define the mass of an atom.
Sum of protons and neutrons.
What did Chadwick do?
Chadwick discovered neutrons which proved isotopes had the same number of protons but a differnet number of protons.
Why is this not endothermic?
Because it is exothermic.
Describe the method to find reactivity?
Combine all of the metals to acid of choice nut must have the same concentration . Next measure the temperature change using a digital themometer to improve accuracy. Place the metals in ascending order of temperature change then you can see the position of this unknown metal.
Why can electrolysis cant happen?
Solid zinc chloride cannot conduct electricity.
Why does graphite conduct electricity?
Each atom forms 3 covalent bonds one electron per atom is delocalised so electrons can carry charge throughout the graphite.
How to change the apparatus?
Use measuring cylinders.
Describe the trend.
Volume of hydrogen is directly proportional to the time.
the rate of collection of hydrogen is 0.45 (cm3/min)
Suggest the reason for the diffeence in volume of each fas collected?
Because the chlorine reacts with water.
Producte of pottasium iodine.
Pottasium chloride and iodine
Why is chlorine more reactive than iodine.
Chlorine outer shell is closer to the nucleus so the chlorine nucleus has bigger attraction for outer electrons
(so) chlorine gains an electron more easily which makes it more reactive than iodine.
Why is hydrogen chloride a gas a room temperature?
hydrogen chloride is made of small molecules
which have weak intermolecular forces so they are a gas because of these forces.
One hazard with chlorine.
Chlorine is toxic to human health.
Why is it bad if water reacts with sodium.
It is explosive.
Why is it carried im argon athmosphere?
Oxygen would react with sodium but argon wont as it is inert.
Why would titanium chloride not be a liquid?
Metal chloride is ionic so they are a solid at room temperature as they have electrostic forces between the ions.
Why is this oxidation?
Sodium loses electrons.
Half equation for oxidation reaction.
Na + E-
Why is a acid strong and dilute?
(strong because) completely ionised (in aqueous solution)
(dilute because) small amount of acid per unit volume
pH
5.0
Why should the student use a pippete.?
pipette measures volume (accurately)
(but burette measures drop by drop.
