4 Metals React with Sulfuric Acid
Category: Speed of Reaction
Speed of Reaction with Acids
Define the term catalyst.
A catalyst is a substance which increases the speed of a chemical reaction, but remains chemically unchanged at the end of the reaction.
List 3 common catalysts used in industrial processes.
– iron: in Haber Process, to manufacture ammonia
– vanadium(V) oxide: in manufacture of sulfuric acid
– platinum or rhodium: in catalytic converters
– aluminium oxide or silicon(IV) oxide: in the cracking process for producing hydrogen
With reference to the graph, explain the progress of the reaction.
At the start, the gradient of the curve is the steepest. This shows that speed of reaction is the highest at the start. The concentration of the reacting particles is the highest at the start, resulting in highest speed of reaction.
As the reaction progresses, the gradient of the curve decreases. This shows that speed of reaction is slowing down. As the reactants are used up in the reaction, the concentration of reacting particles decreases, resulting in a decrease in speed of reaction.
When the gradient of the curve becomes horizontal, it shows that the reaction has stopped. Either one or all of the reactants have been completely used up, so reaction stopped.
Describe an experiment to study the speed of reaction between calcium carbonate and dilute hydrochloric acid, by measuring the loss in mass of reaction system over time.
The apparatus is set up as shown in the diagram below.
The initial mass of the reaction system is recorded.
The thread is pulled to mix the calcium carbonate and acid. The stopwatch is started at the same time.
The mass of the reaction system is recorded every one-minute.
From the data collected, a graph of mass of reaction system against time taken is plotted.
From the slope of the graph, the speed of reaction can be studied.
The steeper the gradient of the graph, the faster the speed of reaction.
Describe an experiment to study the speed of reaction between dilute hydrochloric acid and magnesium, by measuring the volume of gas produced over time.
The apparatus is set up as shown in the diagram below.
The thread is pulled to mix the magnesium ribbon and acid. The stopwatch is started at the same time.
The volume of hydrogen collected in the gas syringe is recorded every half-minute.
From the data collected, a graph of volume of gas produced against time taken is plotted.
From the slope of the graph, the speed of reaction can be studied.
The steeper the gradient of the graph, the faster the speed of reaction.