Calculating and explaining energy changes Flashcards
What does the reaction of hydrogen and oxygen make?
They react and give out energy,
They produce water which isn’t a pollutant
Pros and Cons for using hydrogen gas to power vehicles
Pros:
Produces water, so it’s very clean.
Cons:
Difficult to store
Engines would have to to be adapted
What is a fuel cell
A fuel cell is an electrical cell that’s supplied with a fuel and oxygen and uses energy from the reaction between them to generate electricity
What are the flame tests for metal ions?
The colour tests
What flame does lithium give?
Crimson
What flame does sodium give?
Yellow
Sodium sun yellow
What metal ion gives off a lilac flame?
Potassium
What colour flame does calcium give?
Red
What metal ion gives a green flame?
Barium
Name another test for metal ions
Some metal ions form a coloured precipitate with NaOH
Sodium hydroxide
Why do some metal ions form coloured precipitates with sodium hydroxide
Many metal hydroxides are insoluble and precipitate out of solution when formed
What three metal ions form a white precipitate with sodium hydroxide?
Calcium
Magnesium
Aluminium - what at first but then dissolves in excess to form a colourless solution
What colour precipitate forms when copper (II) reacts with sodium hydroxide
Blue
A green precipitate is formed when sodium hydroxide is added to the metal ion, what is it?
Iron (II)
A blue precipitate is formed when a metal ion reacts with sodium hydroxide, what is it?
Iron (III)
How do you test for carbon dioxide?
It turns limewater cloudy
How can you test for carbonate ions?
Carbonates react with dilute acid to form carbon dioxide, you test for carbon dioxide with lime water
How do you test for chloride bromide and iodide?
Add dilute nitric acid followed by silver nitrate solution
What colour precipitate does chloride give of silver chloride?
White
What colour precipitate does bromide give of silver bromide
Cream
What colour does iodide give of silver iodide?
Yellow
What are the three coloured precipitates formed with hallide ions?
Chloride = white
Bromide = cream
Iodide = yellow
Remember as the alphabet increases the colour intensity increases
How can you text for sulfate ions?
Add dilute hydrochloric acid followed by barium chloride solution.
A white precipitate of barium sulfate means the original compound was a sulfate.
