Chemistry - PPQ Flashcards
How do you collect carbon dioxide from a reaction?
Downward displacement of air
As it is more dense it will fall below the air
What is the chemical equation for the reduction of Fe2O3 by carbon monoxide?
Fe2O3 + 3CO -> 2Fe + 3CO2
What is the formula of ammonium sulfate?
(NH4)2 SO4
What is the chemical test for ammonium ions?
Add sodium hydroxide
Warm
Place damp red litmus paper in the gas
Goes blue
During a reaction, why is a mixture heated and stirred?
To speed up the reaction
To cause the solid to dissolve quicker
What happens to impurities when they are filtered?
Get caught in the filter paper - become the filtrate
… as they are too large to pass through
What is water in a mixture?
The solvent
What is the solid in a mixture?
The solute
What is seen when a sample of hot, molten sulfur is added to oxygen?
Blue flame
How do you ensure all water has been lost in an experiment?
- Keep reheating
- Until constant mass is achieved
After heating to let crystal form, what do you do?
- Leave to cool
- Filter
- Leave to dry in a warm place
What is the difference in the mixtures in a simple distillation and fractional distillation?
Simple: solid and liquid
Fractional: liquid and liquid
Why are metals good conductors?
- Have delocalized electrons
- which are able to move (and carry charge)
What are the features of a reaction in dynamic equilibrium?
Forward and backward reactions occur at equal times
Forward and backward reactions occur at equal rates
Concentration of reactants and products remains constant
What colour precipitate forms in the chemical test for chloride?
White
