C5 Chemical Changes Flashcards
What’s the equation for a reaction between a metal and an acid?
Metal + Acid —- Salt + Hydrogen
What’s the equation for a reaction between an acid and a base?
Acid + Base —- Salt + Water
What’s the equation for a reaction between an acid and a metal carbonate?
Acid + Metal Carbonate —- Salt + Water + Carbon Dioxide
Describe how a change in the pH of a substance affects its hydrogen ion content
As the pH decreases by one unit, the hydrogen ion concentration of the solution increases by a factor of 10.
What metal carbonates are actually soluble in water?
Group 1 metals
And Ammonia (which isn’t a group 1 metal but yh)
What is the difference between a base and an alkali
Bases and alkalis both neutralise acids. A base that can dissolve in water is an alkali, and includes soluble metal hydroxides
Bases - insoluble metal hydroxides and metal oxides
Nitric acid is a strong acid, Methanoic acid is a weak acid. Explain why a solution of methanoic acid would have a greater pH than one of nitric acid [3]
nitric acid is a strong acid so all the HNO3 molecules ionise
in water
methanoic acid is a weak acid so most of its molecules
stay un-ionised / only a few molecules ionise and split up to
form H+
(aq) ions in a reversible reaction
so fewer H+ ions in a given volume of methanoic acid
solution compared with same volume of nitric acid solution
A student heats a copper sulfate solution in an evaporating basin until all the water has boiled. How can the student change this methods to produce larger crystals of copper sulfate? [2]
heat for a few minutes
leave in a warm place to evaporate
Describe the difference that would be observed is an alkali was reacted with acid 1, (a strong acid), and then acid 2 (a weak acid) of the same concentration [2]
effervescence with acid 2
would be slower
What is the definition of a base?
A substance that can neutralise an acid to produce a salt
