help plz ..dissolved C02 on the pH of water (1 Viewer)

[homijoe]

for the method of this experiment is allowed to have the reaction between hydrochloric acid and calcium carbonate in the same beaker with the distilled water or MUST they be separate in other words one test tube containing hydrochlroic acid and calcium carbonate and the co2 produced is transferred to the beaker water via a delievery tube is possible to use either of the 2 methods? or do the hydrochloric acid AND calcium carbnate have to be separated from the beaker of water???

 

[forkyspoony18]

what is the actual syllabus dot point that this experiment comes from?
because i cant really understand what experiment you are talking about, and if you can tell us the correct dot point, it will make it alot easier to help you

 

[Undermyskin]

Separate beakers and you use delivery tube. It's rather simple. You can blow through a straw as well. It's pretty fun. Er... and we tried the fermentation as well... awesome. Indicator: methyl orange. Have fun!

 

[homijoe]

what is the actual syllabus dot point that this experiment comes from?
because i cant really understand what experiment you are talking about, and if you can tell us the correct dot point, it will make it alot easier to help you

sorry dude its this one:

perform a first-hand investigation to demonstrate the effect of dissolved carbon dioxide on the pH of water

 

[forkyspoony18]

when i did that experiment, we showed that humans breathed out CO2 by blowing into limewater and turning it milky. So then we tested the pH of distilled water, and then got a straw and blew into the distilled water, as this was adding CO2 to the water.

I didnt do anything with other chemicals... so im not really sure what your talking about sorry!

 

[axlenatore]

for the method of this experiment is allowed to have the reaction between hydrochloric acid and calcium carbonate in the same beaker with the distilled water or MUST they be separate in other words one test tube containing hydrochlroic acid and calcium carbonate and the co2 produced is transferred to the beaker water via a delievery tube is possible to use either of the 2 methods? or do the hydrochloric acid AND calcium carbnate have to be separated from the beaker of water???

We did two experiments for this, firstly we breathed through a straw into a test tube containing limewater, which went milky showing the presence of CO2, which was followed by breathing into a test tube with distilled water and universal indicator (testing qualatively) to show how CO2 turned solution acidic, we also used a data logger to do this test quantatively. This experiement its completely vaild as the breath contains compounds other than CO2 which may impact on the pH of the water so we did another experiement with a pure source of CO2

We put a couple of marble chips into a conical flash, which had a stopper in the top and a delivery tube which went into a test tube or breaker. The test tube contained distilled water and a little universal indicator. (before this test with limewater to prove that you are getting a pure source) Hydrochloric acid was added to the conical flask resulting in bubbles coming out the other end of the delivery tube cause the universal indicator the change to a different colour, this is also tested with a data logger to show it quanatatively.
Equation- Marble chip is Calcium Carbonate
CaCO3 + 2HCl --> CaCl2 + CO2 + H20

 

[skamerman]

Hey
We did a really easy one- 2 beakers of water- use universal indicator to measure pH first- then blow in each with a straw for 2-3 mins and observe change . We got from 7 to 5 after CO2 added = CO2 makes H2O acidic

 

[danz90]

The acidic nature of CO2:

CO2 + H2O --> H2CO3(aq)

H2CO3 ---> 2H+ + (CO3)2-

Its the H+ from the carbonic acid, which is produced by CO2 reacting with water... which lowers the pH.
As H+ increases, pH decreases.

 

[brenton1987]

CO2 + H2O --> H2CO3(aq)
H2CO3 ---> 2H+ + (CO3)2-

You missed a step

CO_{2 (g)} --> CO_{2 (aq)}
CO_{2 (aq)} + H₂O --> H₂CO_{3 (aq)}
H₂CO_{3 (aq)} + H₂O --> HCO₃^-_(aq) + H₃O⁺_(aq)

 

[danz90]

You missed a step

CO_{2 (g)} --> CO_{2 (aq)}
CO_{2 (aq)} + H₂O --> H₂CO_{3 (aq)}
H₂CO_{3 (aq)} + H₂O --> HCO₃^-_(aq) + H₃O⁺_(aq)

Yeah, that's true. But for the purpose of Bio.. I don't think they need us to show the donating of proton to water by H2CO3. In most textbooks, I see it simply as H2CO3 forming H+ ions and bicarbonate ions.

 

[Kathryn2630]

when i did that experiment, we showed that humans breathed out CO2 by blowing into limewater and turning it milky. So then we tested the pH of distilled water, and then got a straw and blew into the distilled water, as this was adding CO2 to the water.

I didnt do anything with other chemicals... so im not really sure what your talking about sorry!

the second one was a control, to show wat was changing the pH of the water. its the important part.

 

[JacintaLeax]

We just used two test tubes and blew into a straw into one of the test tubes.
then tested the pH.
was a random experiment.

 

[aimzlouise]

For this experiment we used to 2 test tubes and aplaced HCl in one with the carbon dioxide and the distilled water in a sepreate test tube. and used a delivery tube. The test tube with distilled water contained drops of universal indicator to show the change in the pH. We then repeated it again to show reliability. This experiment was our practice one for our task coming up.