2 Acids, bases and salt preparations Flashcards
What is a salt?
It is a compound formed when a hydrogen is replaced by a metal or ammonium in an acid.
What are three examples of salts?
- Magnesium sulfate.
- Zinc chloride.
- Potassium nitrate.
What is hydrochloric acid?
An acid.
What is the formula for hydrochloric acid?
HCI.
What is an example of a salt with hydrochloric acid?
NaCI
What are the names of salts stemmed from hydrochloric acid?
Chlorides.
What is nitric acid?
An acid.
What is the formula for nitric acid?
HNO3
What is an example of a salt with nitric acid?
KNO3
What are the names of salts stemmed from nitric acid?
Nitrates.
What is sulfuric acid?
An acid.
What is the formula for sulfuric acid?
H2SO4
What is an example of a salt with sulfuric acid?
CuSO4
What are the names of salts stemmed from sulfuric acid?
Sulfates.
What is ethanoic acid?
An acid.
What is the formula for ethanoic acid?
CH3COOH
What is an example of a salt with ethanoic acid?
CH3COONa
What are the names of salts stemmed from ethanoic acid?
Ethanoates.
What is phosphoric acid?
An acid.
What is the formula for phosphoric acid?
H3PO4
What is an example of a salt with phosphoric acid?
K3PO4.
What is the name of salts stemmed from phosphoric acid?
Phosphates.
What is so special about sulfuric acid?
It can be thought of as the parent acid of all the sulfates.
What is the parent acid?
The acid from which a salt is formed, for example the sulfuric acid is the parent acid of all sulfates.
What happens if the replacement of the hydrogen can’t be done directly?
It doesn’t matter.
What is an example of this?
You can’t make copper sulfate from copper and dilute sulfuric acid because they don’t react. There are, however, other ways of making it from sulfuric acid - copper sulfate is still a salt.
When are salts also formed?
When the hydrogen in an acid is replaced with NH4.
What is it called when the hydrogen in an acid is replaced with NH4?
Ammonium salts.
- NH4CI (ammonium chloride)
- (NH4)2SO4 (ammonium sulfate)
What are the different types of reactions of acids?
- Reacting acids with metals.
How do dilute acids react with metals?
Depending on their positions in the reactivity series.
What are the ways that dilute acids react?
- Metals below hydrogen in the series don’t react with dilute acids.
- Metals above hydrogen in the series react to produce hydrogen gas.
- The higher the metal is in the reactivity series, the more vigorous the reaction.
Why would you never mix metals such as sodium or potassium with acids?
Because their reactions are too violent.
What is a summary equation for metals above hydrogen in the reactivity series?
Metal + Acid —> Salt + Hydrogen
What are the types of reactions involving magnesium and acids?
- With dilute sulfuric acid.
- With dilute hydrochloric acid.
What are the reactions with dilute sulfuric acid?
There is a rapid fizzing and a colourless gas is evolved, which pops with a lighted sprint (the test for hydrogen).
What happens during this reaction?
The reaction mixture becomes very warm as heat is produced.
What does the magnesium gradually disappear to leave?
A colourless solution of magnesium sulfate.
What is an equation to show magnesium reacting with dilute sulfuric acid?
Mg + H2SO4 —> MgSO4 + H2
What kind of reaction is it between magnesium and dilute sulfuric acid?
This is a displacement reaction. The more reactive magnesium has displaced the less reactive hydrogen.
What happens during the reaction of magnesium with dilute hydrochloric acid?
The reaction looks exactly the same. The only difference is that this time a solution of magnesium chloride is formed.
What is the equation to show the reaction between magnesium and dilute hydrochloric acid?
Mg + 2HCI —> MgCI + H2
What happens to MgSO4?
Ionic compounds are present as separate ions in solution so in MgSO4, Mg2+ and the SO42- ions are separated from eachother.
What are the reactions involving zinc and acids?
The reactions between zinc and two acids look exactly the same.
Why are the reactions of zinc slower than those of magnesium?
The reactions are slower because zinc is lower down the reactivity series that magnesium.
What is the equation for the reaction between zinc and sulfuric acid?
Zn + H2SO4 —> ZnSO4 + H2
What is the equation for the reaction between zinc and dilute hydrochloric acid?
Zn + 2HCI —> ZnCI2 + H2
What is reacting acids with bases?
Metal oxides, such as copper oxide and magnesium oxide, are bases.
What is the reaction between dilute sulfuric acid and copper oxide?
The copper oxide (black powder) reacts with dilute sulfuric acid to produce a blue solution of copper sulfate.
What is the equation of reacting dilute sulfuric acid with copper oxide?
CuO + H2SO4 —> CuSO4 + H2O
What do all the metal oxide and acid combinations behave like?
In the same way as the reaction between copper oxide and sulfuric acid. They produce a salt and a water.
What needs to be present for most of these reactions?
Heat.
What is an explanation of the equation above?
Coper (II) oxide is an ionic compound containing the O2- ion. What has happened in this reaction is that the H+ ions from the acid have combined with the O2- ions to form water (H2O).
What is the general equation for the reaction of a metal oxide with an acid?
Metal oxide + acid —> Salt + Water
What kind of reaction is this?
A neutralisation reaction.
How do we know that this is a neutralisation reaction?
Because the base neutralises the reaction (water is formed).
What do metal oxides that are soluble in water react and react with it to form?
Solutions of metal hydroxides.
What is an example of this reaction?
Na2O + H2O —> 2NaOH