Chemical Changes Flashcards
chlorine + sodium bromide
sodium chloride + bromine
chlorine + sodium iodide
sodium chloride + iodine
aluminium sulfate + magnesium
magnesium sulfate + aluminium
calcium chloride + sodium
sodium chloride + calcium
platinum sulfate + gold
gold sulfate + platinum
zinc sulfate + magnesium
magnesium sulfate + zinc
zinc + copper sulfate
zinc sulfate + copper
Which is more reactive, zinc or lead?
zinc.
Which is more reactive, sodium or aluminium?
sodium.
Which is more reactive, magnesium or calcium?
calcium.
In terms of reactivity, which metal displaces which?
A more reactive metal displaces a less reactive metal.
How are unreactive metals extracted? Give an example.
Unreactive metals, such as gold, can be separated by physical methods.
How can metal be extracted from compounds?
Using a more reactive metal.
How can metals which are less reactive than carbon be extracted?
By heating them with carbon. A reduction reaction takes place as the carbon removes the oxygen from the oxide.
How can metals which are more reactive than carbon be extracted?
By electrolysis of the molten metal compound.
How can salts be produced from a metal?
By reacting it with an acid.
What is the overall charge of salts? Why is this?
The overall charge of salts is zero, as the metal ions are positive, and the ions from the acid are negative.
What is the formula for magnesium nitrate?
Mg2+ and NO3-
- Mg is 2+
- NO3 is 1-
- The ratio is 2:1.
- So, there must be two NO3.
The formula is: Mg(NO3)2
How are copper sulfate crystals made from copper oxide?
- Add the copper oxide (in excess) to sulfuric acid, forming copper sulfate and water.
- Filter the solution to remove excess copper oxide.
- Evaporate some of the water with a bunsen burner.
- Leave the rest to evaporate slowly on a window seal.
What two other ways can salts be obtained by?
- Neutralisation (acid and alkali).
- Reacting a carbonate with an acid.
What ions are produced when acids are added to water?
Hydrogen ions (H+).
What are bases?
Bases are compounds that react with acids and neutralise them, for example, metal oxides and metal hydroxides.
What are alkalis?
Alkalis are bases that dissolve in water to make alkaline solutions. They are soluble hydroxides and produce hydroxide ions (OH-) in the solution.
What are strong acids?
Acids that ionise completely in aqueous solutions.
What are weak acids?
Acids that do not completely ionise.
What is the relationship between concentration and pH of H+ ions?
As the concentration decreases, the pH of the solution increases. As the concentration increases by a factor of 10, the pH value decreases by one unit.
