C4 Predicting and Identifying Reactions and Products Flashcards
What happens when alkali metals react with air?
They can tarnish and go dull, because they have become covered in a layer of metal oxide.
What happens when alkali metals react with chlorine?
A vigorous chemical reaction takes place and a white crystalline salt is formed.
What happens when alkali metals react with water?
A quick and vigorous chemical reaction takes place, giving off hydrogen gas and forming a metal hydroxide, which dissolves in water to form an aqueous alkaline solution.
Describe the Halogen colours
Fluorine, very reactive, poisonous yellow gas at room temp.
Chlorine, fairly reactive, poisonous dense green gas at r .t
Bromine, dense poisonous orange volatile liquid at r.t - forms an orange gas
Iodine is dark grey crstalline solid at room temp or a purple vapour.
(Goes from gases to solid - shows a trend in melt and boiling points.)
What happens in displacement reactions of halogens?
If an aqueous halide solution reacts with a more reactive halogen than is present (one further up the group), the more reactive halogen will displace the other, to form a different halide.
What happens when halogens and alkali metals react?
A halide- an ionic compound of a halogen and an alkali metal, e.g. lithium chloride, sodium bromide- is produced in an exothermic reaction. These compounds conduct electricity when molten or dissolved in water. The reaction becomes less vigorous as you go down the group of .metals.
Why do molten salts conduct electricity?
Salts are ionic compounds, which means they have a regular lattice of positively and negatively charged ions. When they are molten or dissolved in water, they can conduct electricity because the ions are free to move around and carry electric charges They cannot conduct electricity in a solid form as there are strong forces of attraction between oppositely charged ionic bonds meaning electrons cannot move.
All nitrates
Are soluble
All potassium salts
Are soluble
All sodium salts
Are soluble
All silver salts
Are insoluble
Barium sulfate
Is insoluble
Calcium carbonate
Is insoluble
Hydroxides of non-Group 1 metals
Are insoluble
Copper hydroxide precipitate
Light blue
Iron (II) hydroxide precipitate
Green
Iron (III) hydroxide precipitate
Red - brown
Calcium hydroxide precipitate
White (insoluble in excess NaOH)
Zinc hydroxide precipitate
White (soluble in excess NaOH)
When investigating the metal ion
You add a small volume of dilute sodium hydroxide to a solution of substance.
When investigating the non-metal ions, Cl, Br and I.
Acidify with dilute nitric acid and then acid silver nitrate solution.
Chlorine precipitate
White
Bromine precipitate
Cream
Iodine precipitate
Yellow
Sulphate precipitate
White
When investigating the non-metal ion, SO4 2-
Acidify and add barium chloride / nitrate solution
Calcite formula
CaCO3
Quartz formula
SiO2
How can we test if hydrogen is present when putting a metal into dilute acid?
The squeaky pop test, through the use of a burning splint
Why does copper not react with dilute acids at all?
Because it is less reactive than hydrogen
Hydrochloric acid will always produce what kind of salt?
Chloride salts, e.g:
Magnesium chloride
Aluminium chloride
Zinc chloride
Sulfuric acid will always produce what kind of salt?
Sulfate salts, e.g:
Magnesium sulfate
Aluminium sulfate
Zinc sulfate
