Paper 1 Flashcards
What is filtration?
Is used to separate an insoluble solid from a liquid via filtration paper and filtering out bigger stuff.
What is Distillation?
Is used to separate a liquid from any solids which are dissolved in it in order to collect the liquid. this is done by heating the solution and evaporating the water through a pipe into a separate beaker.
What is chromatography?
Can be used to separate small amounts of a solution. Most commonly used to separate pigments in ink. Chromatography paper is used wit a bit sitting in a solvent at the bottom and a few dots of the solution/ink about a centimetre up. As different solids have different levels of solubility, some solids will travel further up the paper, separate from the rest.
How to work out the Rf value of a chromatogram.
Rf value = distance moved by spot/distance moved by solvent.
How do you work out concentration?
formula
amount of solute/volume of solution
What is the sum of protons and neutrons in an atom
362.7
no its the mass number squid-for-brains
How do you work out percentage composition by mass of and element?
(Mass of one element/formula mass of compound) x 100
How do you work out the number of moles?
mass/formula mass
mass moles I formula mass
How do you work out the empirical formula of a compound?
1) write the symbol of each element
C H
2)write the mass of each element in g
8 2
3)Write down Ar of each element
12 1
4) do mass/Ar
0.667 2
5)divide each answer by the
smallest answer (0.667)
1 3
6) write as the formula
so that there is one carbon and three hydrogens
CH3
How do you Work out the mass of reactants to use and what mass of products will be formed?
carbon + oxygen = carbon dioxide
c + O2 = CO2
12 + 2x16 = 12 + (2 x 16)
12g + 32g = 44g
What will a acid + metal make?
salt solution + hydrogen
What will a acid + metal oxide make?
Salt solution + water
What will a acid + metal carbonate make?
salt solution + water + co2
acid + metal hydroxide (alkali) make?
salt solution + water
What does being more acidic mean in relation to H ions
The more acidic, the more H+ ions.
Why is a weak acid weak?
Because it hasn’t fully dissociated meaning not all the molecules have split up to release H+ ions.
What are the chemical properties of an acid?
- Ph less than 7
- Turn litmus paper red
- when dissolved in a solution, H+ ions are released
- strong acids are fully ionised meaning all H+ ions have been released
What does being a strong alkaline mean?
When a alkaline has fully ionised and all OH- ions have been released.
What are the chemical properties of an alkaline?
- A PH above 7
- turns litmus paper blue
- Releases OH- ions when dissolved a solution
- A strong alkali is fully ionised and all OH- ions have been released
Why does A neutralisation reaction between acids and alkalis result in water?
Because H+ + OH- = H20
How do you write and ionic equation?
1) write it balanced
2) split up any aqueous (aq) into ions
3) cross of anything which appears on both sides
What is electrolysis?
Electrolysis is the process by which ionic substances are broken down into simpler substances by passing electricity through them. During electrolysis, metals and gases may form at the electrodes.
Why can electrolysis only happen in a solution/ molten state?
For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted. For example, if electricity is passed through molten lead bromide, the lead bromide is broken down to form lead and bromine.
What happens during electrolysis?
A current gets passed through an ionic solution (or molten). The anions (negative ions) are attracted to the anode (positive electrode) and the cations (positive ions) are attracted to the cathode (negative electrode).
What is the positive electrode called?
The anode
What is the negative electrode called?
cathode
What are negative ions called?
anions
What are positive ions called?
cations
What is oxidation in electrolysis?
The loss of electrons
What is reduction in electrolysis?
The gain of electrons
What electrode are anions attracted to?
the anode
what electrode are cations attracted to?
the cathode
What is produced at the cathode during electrolysis?
Hydrogen, unless the compound being electrolysed contains a metal less reactive than hydrogen.
In that case, that metal is produced instead.
What is produced at the anode?
Oxygen is produced unless the compound contains halide ions (Cl-, Br-, l-). In which case:
- chlorides produce Cl2
- bromides produce Br2
- iodides produce I2 (iodine)
What is an electrolyte?
An ionic compound in molten state or dissolved in water.
What is produced when a metal reacts with water?
Metal hydroxide + water
Why does aluminium react slowly with water or acid?
Because it has a layer of aluminium oxide that stops water from reaching the metal below
What does hydrogen mark in the reactivity series?
The point at which metals lower in reactivity do not react with water or dilute acid
What metals are lower than hydrogen in the reactivity series?
Hydrogen
Copper
Silver
Gold
What would you notice in the reaction between a more reactive metal and less reactive compound?
The more reactive metal will replace the less reactive metal in the compound.
This means that colour will change as the metal leaves the compound to be replaced by a different coloured metal.
Also a coloured film may appear on the surface depending on the colour of the less reactive metal.
Why are alloys stronger than normal metals usually?
because they have different sized atoms, preventing them from sliding over one another.
