Chemistry S3 Revision 2017 Flashcards
What are the seven separation techniques?
The seven separation techniques are:
Heating
Distillation
Electrolysis
Filtration
Chromatography
Magnetism
Evaporation
What is RF values in chromatography?
RF distance moved by the compound ÷ distance moved by the the solvent.
The RF value of a particular compound is always the same - if the chromatography has been carried out in the same way.
This allows industry to use chromatography to identify compounds in mixtures.
What is the reactivity of metals?
If an acid is added to a metal the metal will be quickly corroded by the acid.
We can see a reaction happening because the mixture fizzes and the metal eventual disappears.
Some metals like gold are so unreactive that nothing will happen.
What is the reactivity series?
The order of the reactivity series is:
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Lead
Hydrogen
Copper
Silver
Gold
Platinum.
What is the poem for the reactivity series?
Postman Sends Cards (with) Money And Coins (to the) Zoo in Liverpool His Coins (were) Silver Gold Platinum.
What is electrolysis?
Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity. During electrolysis metals and gases may form at the electrodes.
What is neutralisation?
Neutralisation is the process where an acid (PH 1-6) neutralises an alkali (PH 8-14) to form an neutralised substances (PH7).
All acids contain Hydrogen
This can be tested using the squeaky pop test.
All alkalis contain oxygen + hydrogen.
This can be tested using the re- light spill.
What are acids and alkalis measured on?
Acids and acids are measured on a PH scale.
What’s the solute?
The solute is the solid that is added to the solvent.
What’s the solvent?
The solvent is the liquid the solute is added to.
What’s the solution?
The solution is the dissolved mixture of the solute and solvent.
What is a displacement reaction?
A displacement reaction is where a more reactive metal displaces (pushes out) a less reactive metal from its compound.
What does the atomic structure contain?
Atoms are neutral- they have no charge overall because they have the same number of protons as electrons.
The atomic number tells you how many protons there are.
What is a Chromatogram
A Chromatogram is a visible record (such as a graph) showing the result of separating the components of a mixture by Chromatography.
What is chromatography?
Chromatography can be used to separate mixtures of coloured compounds. Mixtures that are suitable for separation by chromatography, include inks, dyes and colouring agents in food.
What are empirical formulas?
Empirical formulas are used to work out the ratio of elements in a compound, in order to be able to write a formula.
What are flame tests?
They are used to detect the presence of a particular metal ion in compound.
Metal ions change the colour of a flame when they are heated in it.
Different metal ions give different ions give different colours, to the flame.
How would you carry out a typical flame test?
This is how you would carry out a typical flame test:
Dip a clean flame test loop in the sample solution.
Hold the flame test loop at the edge of a bunsen burner flame.
Observe the changed of the flame and decide which metal it indicates.
Clean the loop in acid and rinse with water, then repeat steps in 1 to 3 with a new sample.
Who is the first inventor of the periodic table?
1) Antoine Lavaiosier- French.
In the Periodic Table he put:
Light, Heat
Magnesium oxide- all not an element.
Who is the second inventor of the periodic table?
2) Johann Dobereiner- German
He put in a group of tried elements:
Lithium- Li
Potassium- K
Sodium- Na.
Who is the third inventor of the periodic table?
Dimiti Mendeleev- Russian
He was the ‘father of the periodic table’. He also made the original periodic table.
Atomic mass corresponded into relative molecular mass.
He used estimated patterns to estimate the atomic masses of unknown elements.
He found out that metals such as solids, liquids or gases were good conductors of heat.
In 1789 he authored a book on his findings ‘The Father of the Modern Science’.
More elements discovered, didn’t fit triads, so in the tables still today, so in the tables still today, they are left out until found out.
The elements of the table were organised horizontally based on their increasing atomic mass.
How many elements were in the table?
80.
Describe the structure of an atom.
1) The nucleus
It’s the middle of the atom
It contains protons and electrons.
It has a positive charge because of the protons.
Almost the whole mass of the body’s concentrated in the nucleus.
2) The Electrons
Electrons have virtually no mass
Move around the nucleus in atom shells.
Explain energy changes that take place during chemical reactions.
Energy changes take place during chemical reactions. Exothermic reactions give out thermal energy and endothermic reactions take in thermal energy.
These changes can be measured experimentally or calculated before being analysed. Knowing the amount of energy involved in a reaction can be used to ensure that resources are used efficiently.
The amount of energy transferred can be used by calorimetry.
Which metal could be used to displace sodium from sodium chloride in the reactivity series?
Potassium because its more reactive.
Name two metals that can only be extracted by electrolysis.
Potassium and sodium.
Name a metal that could be extracted from its ore using carbon.
Iron.
Suggest a reason why iron is extracted using carbon rather than by electrolysis.
Iron is extracted using carbon rather than by electrolysis because it is found in ores and not in native state and therefore the oxygen needs to be removed.
Suggest reason why gold is expensive, even though it is found native in rock.
Gold is expensive, even though it is found native in rock because its rare therefore it is hard to find (locate. There’s not lots found in the Earth’s crust.
Also people have already mined for it so there is not much left.
What are the rules for atomic configuration?
Groups- how many electrons in outer shell.
Periods- how many shells the element will have.
1st- Look at periods, draw the relevant numbers of shells.
Always count up number of electrons at the end and always work out the configurations and then see if it matches the atomic numbers.
How many electrons are in the 1st shell?
2 electrons.
How many electrons are in the 2nd shell?
8 electrons ( check the atomic number because it could change.
How many electrons are in the 3rd shell?
8 electrons.
