CHEMISTRY - Chemical Changes, Electrolysis Flashcards
What does OIL RIG stand for in terms of electrons?
Oxidation is loss.
Reduction is gain.
Have a look at the laminated sheet on how to prepare a dry sample of a soluble salt from an insoluble oxide or carbonate.
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What is meant by a displacement reaction?
Where a more reactive metal will displace a less reactive metal from a compound.
What are some common ions and their charges?
Nitrate ion - N03,-
Sulphate ion - S04,2-
Hydroxide ion - OH,-
Ammonium ion - NH4,-
Carbonate ion - CO3,2-
Acid + Alkali = ?
Salt + Water
Metal + Acid = ?
Salt + hydrogen
Metal oxide + Acid = ?
Metal Hydroxide + Acid = ?
Salt + Water
Metal carbonate + Acid = ?
Salt + CO2 + Water
When dissolved in water, which ions do acids produce?
Hydrogen ions.
When dissolved in water, which ions do alkalis produce?
Hydroxide ions.
What charge do elements in group 1,2,3,6,7 have?
Group 1 = +1
Group 2 = +2
Group 3 = +3
Group 6 = -2
Group 7 = -1
What is the relationship between the hydrogen ion concentration and the strength of an acid?
Strong acids have a higher hydrogen concentration than weak acids because they completely ionise unlike weak acids which don’t.
What is the order of reactivity series?
Potassium
Sodium
Calcium
Magnesium
Aluminum
Carbon
Zinc
Iron
Lead
Hydrogen
Copper
Silver
Gold
Platinum
Why does electrolysis only work with aqueous or molten ionic compounds?
The ions need to be free to move and are not able to do this in solids, liquids or gases.
Have a look at the laminated sheet and learn how to write ionic equations from symbol equations.
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What happens when metals react with other substances?
Metal atoms lose electrons to form positive ions.
What are some signs to show whether a metal is more reactive or not?
- The more vigorous its reactions are
- The more easily it loses electrons in reactions to form positive ions (cations)
Describe and explain the observations when a small piece of lithium is placed on the surface of a big container of water. A few drops of universal indicator have been added to the water.
There is fizzing as the lithium reacts with the water to produce hydrogen gas. The colour of the universal indicator changes from green to purple as an alkaline solution of lithium hydroxide is produced.
When is hydrogen produced in a reaction?
When a metal reacts with water or a dilute acid.
What are native metals?
Metals found in the crust naturally, which are unreactive such as gold.
What is an ore?
When a rock contains a high enough percentage of metal atoms to make it profitable..
What are bases?
Substances that neutralize acids.
What is the difference between soluble and insoluble bases?
Soluble bases are known as alkalis whereas insoluble bases are usually metal oxides or metal carbonates where the product won’t dissolve.
When does neutralization occur?
When H+ ions are removed from a solution usually by OH- ions.
When is a solution neutral?
When the concentration of OH- ions is equal to H+ ions.
What is an electrolyte?
The compound on which electrolysis is carried out. They are always ionic compounds.
During electrolysis, where do positive ions go to?
Positive ions move towards the negative electrode (cathode-) and gain electrons to form metallic elements or hydrogen.
During electrolysis, where do negative ions go to?
Negative ions go move towards the positive electrode (anode+) and lose electrons to form non-metallic elements.
Have a look in the orange textbook on page 73 at the electrolysis diagram.
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What does the strength of the acid mean about how ionised
