Chemical reactions are reversible and may reach a dynamic equilibrium. The direction of some reversible reactions is altered by changing the reaction conditions.
Which is the correct symbol to show a reversible reaction?
What happens to the concentrations of reacting substances at equilibrium?
They remain constant
They remain equal to each other
They keep changing
Ammonium chloride decomposes reversibly to form ammonia and hydrogen chloride when heated. What is the backward reaction for this process?
Ammonium chloride → ammonia + hydrogen chloride
Ammonia + hydrogen chloride → ammonium chloride
Ammonia + ammonium chloride → hydrogen chloride
Which of these reactions is most likely to be reversible?
Combustion of petrol to form carbon dioxide and water vapour
The reaction between silver nitrate solution and sodium chloride solution to form a precipitate of silver chloride
The reaction between ammonia gas and hydrogen chloride gas to form ammonium chloride
What happens to the forward and backward reactions at equilibrium?
They keep going
They repeatedly stop then start again
Which statement about a dynamic equilibrium is correct?
It happens only in a closed system
It happens only in a non-enclosed system
It happens in closed and non-enclosed systems
When heated, blue hydrated copper sulfate forms white anhydrous copper sulfate and water. What happens if water is added to anhydrous copper sulfate?
White hydrated copper sulfate forms
Blue hydrated copper sulfate forms
Blue hydrated copper sulfate and water forms
The thermal decomposition of calcium carbonate is reversible: CaCO3 ⇌ CaO + CO2. The forward reaction is endothermic. What happens to the position of equilibrium when the reaction mixture is heated?
It moves to the left
It does not change
It moves to the right
The thermal decomposition of calcium carbonate is reversible: CaCO3(s) ⇌ CaO(s) + CO2(g). What happens to the position of equilibrium when the pressure is increased? - Higher
Hydrogen can be made by reacting carbon with steam: C(s) + H2O(g) ⇌ H2(g) + CO(g). How can the equilibrium concentration of hydrogen be increased? - Higher
Increase the concentration of steam
Increase the concentration of carbon monoxide
Use less carbon in the reaction