Rate of Reaction Between Calcium Carbonate and Hydrochloric Acid

Collision Theory

The collision theory tells us that for a chemical reaction to take place the two particles reacting must first collide and collide with enough energy to react.

Factors affecting the rate of reaction

HEAT

As the temperature increases so does the rate at which a reaction occurs. As the reacting mixture heats up the particles gain more energy and they move faster, because they move faster there is a greater chance of a collision occurring and when it does occur it is more likely to be a successful collision as the particles of reactant have more energy.

2 CONCENTRATION OF REACTANTS

If the concentration of the reactants is increased then the reaction goes faster. This is because as the concentration of reactants increases the chance of a collision between the particles of reactant increases and the greater the number of successful collisions the faster the rate of reaction.

3 SURFACE AREA

If the surface area of one or more of the reactants is increased then the rate of reaction increases. As the surface area of the reactants increases then the area of contact between the reactants increases which in turn increases the chance of particles colliding. More successful collisions means a faster reaction.

4 PESENCE OF CATYLIST

If a catalyst is present then a collision needs less energy to be successful. More successful collisions means faster rate of reaction.

Variables

* Mass of calcium carbonate

* Volume of acid

* Concentration of acid

* Surface area of marble chips

* Presence of catalyst

* Temperature

Independent variable

* Concentration of acid ( 0.5, 1.0, 1.5, 2.0 + 2.5 M)

Dependant variable

* Volume of CO2 produced every 15 seconds four two and a half minutes.

Controlled variables

* Mass of calcium carbonate

* Volume of acid

* Surface area of marble chips

* Presence of catalyst

* Temperature

Prediction

I think that as the concentration of the acid used increases so will the rate of reaction. This is because as the number of H+ ions present increases the number of collisions between the H+ ions and CaCO3 particles increases and so the number of successful collisions increases and rate of reaction increases.

Method

Apparatus

* Conical flask (100 cm3)

* Delivery tube

* Burette (50 cm3)

* Pneumatic trough

* 60 cm3 Hydrochloric acid (concentrations 0.5 1.0 1.5 2.0 2.5 moles/dm3)

* Marble chips

* Beakers (100 cm3 )

* Filter funnel

* Measuring cylinder( 20 cm3 )

Step by step

. Set up the apparatus as shown in the diagram.

2. Fill the burette up with water and immerse in water up side down. Let the water run out till the water level reaches the fifty mark and place the delivery tube under the burette.

3. Measure out 20 cm2 of the acid being used and put into a conical flask.

4. Drop a one gram marble chips in to the acid quickly place on the bung and start the timing when the first bubble enters the burette.

5. Record the Volume of carbon dioxide every fifteen seconds, for two and a half minutes.

6. Repeat the experiment three times to test reliability.

7. Repeat for all concentrations of acid.

Safety Precautions

* Handle glass objects with care

* Wear glasses to protect eyes

* Handle acid with care

Strategy for dealing results the results

Recordings will be taken every fifteen seconds for two and a half minutes. This will be repeated three times for accuracy. The results will be recorded in a table like the one below.

Concentration of acid _________ M/dm2

Time (seconds)

Volume of CO2 produced (cm2)

2

3

5

30

45

60

75

90

05

20

35

50

When all the results are recorded we can find the average of the three results found at each time with the same concentration of acid. This can then be plotted on a graph as shown. One for each concentration

Based on my prediction I would expect the graph to look like this.

Then I will work out the rate of reaction for each of the concentrations using this formula

Rate of reaction = total amount of carbon dioxide produced

In volume of CO2/min 2 1/2

This could then be plotted on a graph of concentration of acid against rate of reaction as shown below.

I would expect the graph to look like this.