How did mandeleev overcome the problem of undiscovered elements?
Put them in a seperate groups
How were the early periodic tables arranged?
By proton number
By Atomic weight
How is the modern periodic table ordered?
Elements in the same group have the same number of...
Electrons in their outer shell
shells or energy levels
Protons in the nucleus
Characteristics of group 1:
React with non metals to form ionic compounds and carry a +1 charge
React with non metals to form covalent compounds and carry a +1 charge
React with water to release hydrogen
form hydroxides that dissolves in water to give alkaline solutions
The further up the group 1 the more reactive and lower its melting poit
Characteristics of transition elements compared with group1:
higher melting points
lower melting points
stronger and harder
Much less reactive
Much more reactive
Transition metals are useful catalysts
What are group 7 elements known as?
The further down group 7 the less reactive and the higher melting point.
A more reactive halogen can displace a less reactive halogen from an..
Aqueous solution of its salt
Aqueous solution of its oxide
The more energy levels an element has the less reactive it is
Hard water can contain..
Hydrogencarbonate ions (in temporary)
Which type of water form a lather readily?
There are two types of hard water temporary hard water and permanent hard water
Scum is formed by the decomposition of Hydrogencarbonate ions in temporary hard water
What are two ways that hardness can be removed?
Exchange columns and adding sodium carbonate
Heating it and adding calcium carbonate
What are two things that water should have low levels of?
Pure water can be produced by distillation
What do water filters contain to remove some dissolved substances from water?
Silver, carbon and ion exchange resin
Gold, carbon and ion exchange resin
Chlorine is added to water to increase microbes and flourine isn't added to improve dental health
How is energy released from substances measured?
Why in a chemical reaction should the reagents be mixed in an insulated container?
So less energy escapes to the surroundings
So it wont burn the person
so none of the substance leaks out
During a reaction energy is needed to make bonds and energy is released when breaking bonds
Three things to do when drawing an energy diagram:
Show reactants then products
Show activation energy
Overall energy change
Use a red pencil
Draw a best fit line
Show products then reactants
In an exothermic reaction more energy is released to make bonds than break them
Catalysts higher the activation energy
Tick the 4 true facts:
Lithium has a crimson flame
Lithium has a lilac flame
Potassium has a lilac flame
Barium has a blue flame
Barium has a green flame
sodium has a yellow flame
sodium has an orange flame
Aluminium, calcium and magnesium ions form white precipitates
What colour precipitate does copper form?
What colour precipitate does iron (lll) ions form?
What colour precipitate does iron(ll) ions give?
Carbonates react with dilute acid to form carbon dioxide
Halide ions can be tested by adding what and what then looking at the precipitates?
Silver nitrate solution and dilute nitric acid
Silver nitrate solution and hydrochloric acid
silver nitrate solution and barium oxide
To test sulphate ions add hydrochloric acid and barium chloride solution
How can volumes of acid and alkali solutions that react with each other be measured?
What are the raw materials in the haber process?
What is the temperature and pressure in the haber process?
200 atmospheres and 450 degrees
450 atmospheres and 200 degrees
Ammonia is produced in the haber process
Equilibrium is reached when the reactions occur at the same rate in each direction
To increase the yield in a reaction that is exothermic in the forward direction what do you do?
Increase the temperature
Decrease the temperature
What can you do to increase the yield when the forward reaction has more gaseous molecules?
We have to compromise temperature, pressure and rate of reaction in the haber process
Which functional group is for alcohols?
Which functional group is for esters?
What is the functional group for acids?
3 characteristics of alcohols:
burn in air
don't burn in air
React with sodium to produce hydrogen
React with sodium to produce carbon dioxide
dissolve in water to form a neutral solution
Oxidising ethanol makes ethanoic acid
4 characteristics of carboxylic acids:
dissolve in water to produce acidic solutions
dissolve in water to produce alkali solutions
dont ionise completely when dissolved in water so are weak acids
ionise completely with water
react with alcohols in the presence of an acid to produce esters
react with carbonates to produce carbon dioxide