The slides speaks about the complete practical of 'measuring the mass of the gas'

1. Mass of Gas
By: Eiman Rana
MYP-V Armstrong

2. Objective:
 To follow the rate of the reaction between
marble chips (calcium carbonate) and
hydrochloric acid by measuring the mass of
carbon dioxide produced and ‘lost’ over
time
 CaCO3 + 2HCl CaCl2 + CO2 +H2O

3. Equipment
 Eye protection
 250 cm3 conical
flask
 Cotton wool
 Hydrochloric Acid
 Marble chips
 50 cm3 measuring
cylinder
 Piece of paper
 Top-pan balance
 Clock

4. Procedure
 Using the measuring cylinder, put 50 cm3 of HCl in the
conical flask
 Place a loose plug of cotton wool in the neck of the
flask
 Weigh 20g of marble chips
 Measure the balance of flask and marble chips
together
 Press the tare button, so that all apparatus weigh zero
 Remove the cotton wool and add marble chips to the
acid. Start the clock at the same time
 Replace the cotton wool. Put the flask and the paper
on balance
 Read the mass of apparatus after the interval of 30
seconds until the reaction stops

6. Observations
Time (seconds) Reading on balance
(g)
0 0
30 1.5
60 2
90 2.6
120 3.2
150 3.5
180 3.6
210 3.6
240 3.6

7. 0
0.5
1
1.5
2
2.5
3
3.5
4
0 30 60 90 120 150 180 210 240
Series 1

8. Questions
 Why has the apparatus lost mass?
 Gas released
 There were some marble chips left at the
end of the experiment. Why did the
reaction has finished?
 HCl is the limiting reactant
 Look at your graph. How can you tell from
your graph that the reaction has finished?
 Straight line

9.  Calculate the average rate of reaction for first
2 minutes.
 1.86
 Write a word equation for the reaction
between calcium carbonate and hydrochloric
acid.
 Calcium carbonate + hydrochloric acid →
calcium chloride + carbon dioxide + water