We had used the pipette filler to add 25.0 cm3 of sodium carbonate standard solution 1 to the conical flask which was then mixed with approximately 3 drops of the indicator which was the methyl orange. We did the titration practical at least 5 times for accuracy and one of the results was a trial to see when the solution was fully reacted to the hydrochloric acid. The consistency of the volume of the unknown solution 1 which was titrated, was a mean of 0.475 cm3 (from the results of 0.5, 0.5, 0.5, 0.4) and the trial was not included in the mean titre.
The consistency of standard solution 2 was a mean of 0.575 cm3 (the final readings being 0.6, 0.6, 0.5, 0.6). This was a good final reading as each time we did the titration, we had the same readings for the volume used. The consistency of standard solution 3 was a mean of 0.425 cm3 (the final reading being 0.4, 0.4, 0.4, 0.5). The indicator used was the methyl orange which turned the sodium carbonate solution an orange shade, then once the hydrochloric acid was added to the solution it quickly changed to a light pink colour meaning the titration is complete.
The end point for each titration was a mean of 0.475 cm3, 0.575 cm3 and 0.425 cm3. This was accurate because after the trial we then knew when the titration was fully complete and many of our results were repeats.
Sodium Carbonate + Hydrochloric Acid ? Sodium Chloride + Carbon Dioxide + Water
Na2CO3 (s) + 2HCl (aq) ? 2NaCl (aq) + CO2 (g) + H2O (l)
There are 2 ions present in the ionic compound of Sodium Carbonate which are:
The cation is Na+ and is positively charged.
The anion is CO32- and is negatively charged.
Sodium is an alkali and also a metal and it is from the left-hand side of the periodic table. Sodium is in group 1 which means there is only 1 electron on the outer shell. Sodium loses its electron from the outer shell to make it stable and have a fuller outer shell and this then forms a cation with the charge of +1.
The carbonate ions are held together by an ionic bond to the sodium ions. This means that the sodium carbonate has no overall charge because the sodium ions have a charge of 2+ and the carbonate ions have a charge of 2-.
Carbonate ions have a charge of 2- because they share electrons meaning they have a covalent bond. Carbon is in group 4 so it has 4 electrons in its outer shell. This means that the carbon needs 4 more electrons so it will be covalent bond with 3 oxygen atoms to gain a full outer shell.
Oxygen is in group 6 which means it has 6 electrons in its outer shell so it needs to gain 2 more electrons to make it a stable and full outer shell. The carbon atom needs to form a double bond with one of the oxygen atoms so the oxygen atom has a full outer shell. The other oxygen atoms form a single covalent bond but it will only have 7 electrons in the outer shell with the other electrons from the two sodium atoms so the oxygen atoms now have a complete outer shell.
The hydrochloric acid is at the top of group 1 in the periodic table because it only has 1 electron in its outer shell like the rest of the group 1 elements. Hydrogen is also there but it is not an alkali metal, so it has just been placed there. Chlorine is another element which is in group 7. This means it needs 1 more electron to have a stable full outer shell.
Carbon Dioxide is a covalent bond compound because it forms bonds between 2 non-metals. Carbon and oxygen are both non-metals. Carbon Dioxide has 2 oxygen atoms sharing electrons with one carbon atom. Carbon is in group 4 and oxygen is in group 6 so this means they can form a covalent bond.
Water is made up of 2 hydrogen atoms and 1 oxygen atom. The state water is, is liquid. It’s a covalent bond compound because it is formed by two non-metals. Hydrogen has 1 electron and oxygen has 6 electrons in its outer shell. This means that hydrogen needs one more electron to make it a full outer shell. This means we need 2 hydrogen atoms because an oxygen atom needs two more electrons and each hydrogen shares one electron.
b. A standard solution is prepared the same way in labs as they are in industries. However, there are some major differences in making the standard solutions in a lab compared to the industries. In the industry, most of the making is done by an automated machine such as measuring the mass and volume and making it all as accurate as it can be whilst in the lab it is all done manually meaning it is done by people. This shows that the industry makes good quality standard solutions compared to the lab. This is because machines are less likely to make mistakes whereas the people in labs could add too much water that is mixed in the standard solution which means that they would have to repeat the whole experiment again. Though, quality is also affected by the tools and equipment that are used because industries will have a lot more money to buy expensive tools and equipment whereas labs have a budget so it is very restricted. This can show that cost is a huge factor that affects the standard solution massively. Industries will tend to but equipment in bulks while schools and colleges would buy small quantities of equipment, which makes the price higher. Industries will spend a lot of money on equipment on the making of the standard solution as they want to achieve the best they can. In industries, if the quality is poor then it will be thrown way and not used again as they have tests to approve of the quality. If the product does not pass the test then this could be due to contamination. Compared to labs, if the standard solution is contaminated, it will still be used as they do not have enough to make more solutions. If the cost of equipment didn’t matter, then labs will still not be better than industries because they will need the space to add all the big machines and equipment whereas in industries they have big warehouses and factories.