CaCO3 + 2HCl -> CaCl 2 + H2O + CO2
Aim
Investigate factors affecting rate of reaction between calcium carbonate and hydrochloric acid.
Method & Diagram
Fill measuring cylinder with water
Half fill water basin with water
Invert measuring cylinder whilst covering open end with hand
Submerge measuring cylinder (End with hand on)
Put 25ml of acid into the conicle flask
Have 2.0g of marble chips ready
Put end of pipe into submerged conicle flask
Prepare to start stopwatch
Put marble chips in with acid & put bung on conicle flask whilst starting stopwatch
Every 30s starting from 0s take a measurement of how much air there is in measuring cylinder (cm3)
When you have done this with the first concentration of acid clean out the conicle flask and refill the measuring cylinder & repeat experiment with next concentration of acid.
Equipment
* Water
* Conicle Flask
* Bung
* Marble chips
* Water Basin
* Tube
* Acid amounts (0.25M, 0.5M, 1.0M, 1.5M, 2.0M)
* Timer
Vairiables
Concentration of acid -> higher the concentration faster the reaction
Mass of limestone – (Which is not changed other than test specs)
Surface area of limestone – Greater the surface area -> faster rate of reaction
Temperature – Increasing the temp -> increases the reaction rate
Theory
The concentration of acid has a major effect on the results. For our experiment we used 25ml of acid (All of the concentrations used the same amount) 0.25M, 0.5M, 1.0M, 1.5M, 2.0M. ‘M’ Means molar which is how the strength of acid is measured.
The stronger the concentration of acid used will effect the amount of gas produced, the more acid used – the more gas created & visa versa.
Prediction
I predict the more gas made will be dependent on how much acid is added.
Safety
* Use goggle eye protection
* Rinse acid contacted area with water & seek help
Results
Experiment 1
0.25M
0.5M
1.0M
1.5M
2.0M
0
0
0
0
0
0
30
2
4
10
20
30
60
4
6
24
50
64
90
8
8
42
80
114
120
10
14
60
106
146
150
12
16
75
130
178
180
13
18
90
152
204
210
15
30
115
174
222
240
16
42
130
194
244
270
18
52
142
210
265
300
20
58
172
224
277
Experiment 2
0.25M
0.5M
1.0M
1.5M
2.0M
0
0
0
0
0
0
30
3
4
10
15
33
60
5
7
22
40
67
90
7
14
34
75
116
120
9
18
54
100
145
150
11
25
75
125
179
180
12
30
90
144
205
210
14
39
100
160
225
240
16
45
115
180
242
270
17
55
128
196
269
300
20
64
141
208
274
Averages Table
0.25M
0.5M
1.0M
1.5M
2.0M
0
0
0
0
0
0
30
2.5
4
10
17.5
31.5
60
4.5
6.5
23
45
65.5
90
7.5
11
46
77.5
115
120
9.5
16
57
103
145.5
150
11.5
20.5
75
127.5
178.5
180
12.5
24
90
148
204.5
210
14.5
34.5
107.5
167
224
240
16
43.5
122.5
187
243
270
17.5
53.5
135
203
267
300
20
61
156.5
216
275
Conclusion
My results have shown that when i use a stronger acid the rate of reaction between calcium carbonate and hydrochloric acid increases because, there is more contact between particles of acid and particles of calcium carbonate. There is a definate partern to both my graphs and results and this is that the stronger the acid the quicker carbon dioxide was produced. This is shown of the graphs by a steadily increasing line.
This proves my prediction to be correct, because I predicted that a stronger acid would give more carbon dioxide quicker than a weaker acid and this was true. 2.0M acid was so fast compared to 0.5M acid because in 2.0M acid there is a higher concentration of particles of acid so there is more chance of a collision between acid particles and calcium carbonate particles. In 0.5M acid it was so slow because there is a quater of the amount of acid particles in 2.0M acid. I can draw a labelled diagram which shows particles of acid colliding with marble chips and making gas and I can use this to explain what I found out in my results.
Evaluation
I cannot think of a better way of doing the experiment or collecting more accurate results except than using more detailed measuring cylinder’s. I do think that taking averages helps because it gives an average result which means that it can be more accurate than lots of individual results. The main difficulties in doing this experiment I think were taking results accurately.