Chemistry Module 4 Flashcards
How do you test for sulphate ions?
Barium chloride
How do you test for dissolved ions?
Precipitation reactions
How do you test for halide ions?
Silver nitrate
What colour precipitate does chlorine make?
White
What colour precipitate do bromide ions make?
Cream
What colour precipitate do iodide ions make?
Pale yellow
What is thermal decomposition?
Breaking down using heat
What is precipitation?
When a solid forms in solution
When you react some soluble transition metal compounds with sodium hydroxide, what do you get?
An insoluble hydroxide
What do you use precipitation tests to test for?
Transition metal ions
Where does the UK get water from?
Surface water and ground water
What are the steps to purify water in water treatment plants?
Filtration- mesh takes out twigs etc
Sedimentation- adding iron sulphate makes particles clump together and settle at the bottom
Chlorination- chlorine gas kills microbes and harmful bacteria
How can tap water contain impurities?
Nitrates- run off
Lead-pipes
Pesticides from fields
How do you get fresh water?
Distillinga sea water
What kind of structure do metals have?
Crystal
How are metals held together?
Metallic bonds which allow the outer electron to move creating a sea of delocalised electrons
What properties do strong metallic bonds give?
High melting and boiling points, high density
Why are metals good conductors of heat and electricity?
Delocalised electrons carry heat and electrical current
What are superconductors?
Metals at really low temperatures, no resistance
What’s the problem with superconductors?
Expensive to get metals cold enough, less than -265 degrees
What are transition metals?
Metals in the middle of the periodic table
Transition metals and their compounds make good catalysts, give an example
Iron-ammonia-Haber process
Nickel-margarine
What colour is iron(ll)?
Light green
What colour is iron(lll)?
Orange/brown
What colour is a copper compound?
Blue
What are ions?
Charged particles
What is an isotope?
Different forms of the same element which have the same number of protons but a different number of neutrons
Give an example of an isotope
C12 or C14
What is ionic bonding?
Transferring electrons, atoms lose or gain electrons to form charged particles which are attracted to each other
What do ionic compounds form?
Giant ionic lattices
What happens when metals form ions?
They lose electrons to form positive ions
Why happens when non-metals form ions?
They gain electrons to form negative ions
What happens when metals and non-metals combine?
Ionic bonds form
What are covalent bonds?
Sharing electrons
What does each covalent bond provide?
Extra electrons
What do substances formed from covalent bonds have?
Simple molecular structures
What do atoms in molecules have?
Strong covalent bonds
What is the melting/boiling points of simple molecular structures like?
Low melting/boiling points, weak attraction between molecules
Do simple molecular structures conduct electricity?
No, no free electrons
What’s the charge of a neutron?
0
What’s the mass of a proton?
1
What is the charge of an electron?
-1
What’s the mass of a neutron?
1
What’s the charge of a proton?
+1
What’s the mass of an electron?
0
Which number is the mass number?
Top
Which number is the atomic number?
Bottom
What did John Dalton conclude?
Atoms were solid spheres
What did JJ Thomson conclude?
Atoms contained electrons, ‘plum pudding model’
What did Rutherford conclude?
The plum pudding model was wrong, gold foil experiment
What did Bohr conclude?
That electrons were contained in shells
How many outer shell electrons do group 1 have?
1
What do ionic compounds form?
Giant ionic lattices, don’t conduct electricity when solid
Why are MgO and NaCl giant ionic structures?
They have high melting and boiling points, lots of energy is needed to break the bonds
What happens as you go further down group 1?
More reactive, outer electron lost easier, further from nucleus
What are the properties of an alkali metal?
Low melting/boiling point, low density, soft
What is oxidation?
Loss of electrons
What does a reaction with water produce?
Hydrogen gas
What’s the colour of a lithium flame?
Red
What’s the colour of a sodium flame?
Yellow
What’s the colour of a potassium flame?
Lilac
What happens as you go down group 7?
It gets less reactive, melting and boiling points increase
What is reduction?
Gain of electrons
What happens when halogens react with alkali metals?
Salts are formed
What do halogens do?
More reactive halogens displace less reactive ones
