C5 Chemical Changes Flashcards
What does reactivity mean?
how vigorously a substance chemically reacts
How can metals be ordered by their reactivity?
by comparing their reactions with water, acid, or oxygen
What name is given to a list of metals ordered by their reactivity?
reactivity series
In terms of electrons, what makes some metals more reactive than others?
Fewer electrons makes them more reactive as they lose their outer shell electron(s) more easily
Why are gold and silver found naturally as elements in the Earth’s crust?
they are very unreactive
What is an ore?
rock containing enough of a metal compound to be economically worth extracting
How are metals less reactive than carbon extracted from their ores?
reduction with carbon
In terms of oxygen, what is oxidation?
addition of oxygen
In terms of oxygen, what is reduction?
removal of oxygen
Why can metals like potassium and aluminium nor be excracted by reduction with carbon?
they are more reactive than carbon
How are metals more reactive than carbon extracted from their ores
electrolvsis
What is a displacement reaction?
a more reactive substance takes the place of a less reactive substance in a compound
What is an ionic equation?
equation which gives some substances as ions and has spectator ions removed
What type of substance is given as ions in an ionic equation?
ionic compounds in solution (or liquid)
What is a spectator ion?
ion that is unchanged in a reaction
What is a half equation?
equation that shows whether a substance is losing or gaining electrons
In terms of electrons, what is oxidation?
loss of electrons
In terms of electrons, what is reduction?
gain of electrons
In terms of pH, what is an acid?
a solution with a ph of less than 7
In terms of pH, what is a neutral solution?
a solution with a pH of 7
In terms of H+ ions, what is an acid?
a substance that releases H• ions when dissolved in water
How is the arount of H+ ions in a solution related to it’s pH?
the more H* ions, the lower the pH
What are the names and formulae of three main acids.
hydrochloric acid, HCI; sulfuric acid, H2 504; nitric acid, HNO3
How do you measure the pH of a substance?
universal indicator or pH probe
