GCSE Chemistry C3 - Periodic Table, Water and Analysis Flashcards
Cu2+ ions with OH- (hydroxide) ions?
blue precipitate forms Cu(OH)2
How does adding sodium carbonate soften water?
The Mg and Ca ions form a precipitate (carbonate) which can be fitered off. The ions are thus removed
Flame test colour - potassium
potassium - lilac
What 2 products are made when an alkali metal reacts with water?
A hydroxide (alkaline) and hydrogen gas.
Fe3+ ionswith OH- (hydroxide) ions?
rusty brown precipitate forms Fe(OH)3
What are the products when a carbonate reacts with acid?
carbon dioxide, water and a salt.
The alkali metals’ is the name for which group in the periodic table?
Group 1
How is limescale formed?
hydrogen carbonate ions decompose on heating to form solid (precipitate) carbonates
In the periodic table, are elements arranged in order of mass number or atomic number?
Atomic number
What is the key difference between permanent and temporary hard water?
Temporary hardness ca be removed by boiling.
What is the chemical test for sulphate ions?
Add barium chloride solution - a white precipitate forms if a sulhate is present.
Why is chlorine added to our drinking water?
To kill microbes
Flame test colour - barium
barium - green
Which is more reactive - lithium or potassium?
potassium
Which is more likely to form a coloured compound - chromium or calcium?
Chromium - because it is a transition metal.
Which two physical processes are involved in distillation?
boiling and condensing
Fe2+ ions with OH- (hydroxide) ions?
green precipitate forms Fe(OH)2
Al3+ ions with OH- (hydroxide) ions?
White precipitate of Al(OH)3 which dissolves in excess hydroxide
What is the chemical test for chloride ions?
Add silver nitrate + nitric acid - white precipitate forms
Flame test colour - sodium
sodium - yellow
What is the chemical test for carbon dioxide?
Bubble it through lime water - it goes milky / cloudy white as a precipitate forms
Why can’t water softened using ion exchange be given to babies?
The Mg and Ca are replaced by sodium ions. Too much sodium is bad for you.
Describe the trend in reactivity in group 1
As you go down the group they get more reactive.
Which group 7 element, other than chlorine, is sometimes added to water?
Fluorine, for healthy teeth.
What is the chemical test for bromide ions?
Add silver nitrate + nitric acid - cream precipitate forms
Which dissolved ions make water hard?
magnesium and calcium
Is bond breaking an exo or endothermic process?
Endothermic - you put energy in to break bonds
What is the charge on each halide ion?
1- (group 7 - they gain 1 electron to get a full shell of 8 or 18)
Is bond making an exo or endothermic process?
Exothermic - energy is released when bonds are made
What is the chemical test for siodide ions?
Add silver nitrate + nitric acid - yellow precipitate forms
The halogens’ is the name for which group in the periodic table?
Group 7
Give an advantage of living in a hard water area
Calcium in water is good for growing strong teeth and bones. Also reduces heart disease
Flame test colour - lithium
lithium - crimson
Flame test colour - calcium
calcium - red
Ca2+ and Mg 2+ ions with OH- (hydroxide) ions?
White precipitates of Mg(OH)2 and Ca(OH)2 form
