Will I'm sure Billzene will be able to give you a better answer since I'm a bit out of touch with VCE chemistry, but I am pretty sure that the numbers are not necessary for compounds that are implied. For example, no need to write propan-2-one, propanone will suffice (but you actually don't need to know how to name aldehydes and ketones for VCE chemistry anyway)

Jesus
You wouldn't lose marks for writing this.

      Will
      It's super inconsistent. I got a mark taken off on a SAC for writing propan-2-one due to the redundant number, but when I omitted it on my exam, I got a mark taken off there. This might be bad luck since the students I tutor never lost a mark on their exams for including or excluding a redundant position number.

        Hey Billzene,
        Do you know if we need to know which amino acids are essential?

          Will
          You absolutely don't. They'll tell you in the question if an amino acid is essential or non-essential

            13 days later

            hey
            for this questions write an equation that shows hso4- acting as base in water. Would it be. Thank you

            h2so4 + h20 = hso4- + h30+

              chemistry1111
              You’re showing H2SO4 acting as an acid, not HSO4- acting as a base. Remember that bases grab H+ i.e. they neutralise (remove) H3O+ instead of making more H3O+

                hamna_fa
                Hi!

                Edit: I'm completely wrong... Mybad! See Will

                Presuming the standard solution is used to make the titrant/aliquot; here's my understanding!

                - This would mean that the concentration would have been artificially decreased (as the titrant would be diluted).
                - This would mean there would be an overestimation of aliquot added.

                • Meaning the concentration measurement would be greater than the real value.

                Hope this helps!

                    Is the volumetric flask not supposed to be rinsed with only deionsied water?
                    It says the "accuracy of the standard solution", so I'm assuming the volumetric flask is used to make the standard solution. If so, it should be washed with water regardless, as water is added to make these, and it is filled up to a certain point in the beaker.

                    The only thing that is washed with the solution which will go in it is the burette and the pipette, right?

                      Will
                      This is correct. You're filling the volumetric flask with water anyways so it doesn't matter if there's some residual water left. The other glassware you wash with distilled water is the conical flask

                        hamna_fa
                        It's OK since you're going to add more water to the Na2CO3 in the volumetric flask anyways

                          Christ It disrupts the H bonding in 2˚ and 3˚ structures of proteins with its hydroxyl group

                            Greetings,

                            For mass spectroscopy, do we need to know how to write the equation which produces the parent molecular ions and base peaks?
                            I saw it on a VCAA 2010 exam, but not sure if it's within the scope of the new study design.
                            And if so, could anyone provide an example of how you would write it?

                            Thanks,

                            Your Lord

                              Lord I don't think you need to in the new SD. If you're curious, it's M + e- ---> M+ + 2e-. Some people choose to show it with a radical ie M+. but I don't

                                5 days later

                                Hey guys I have a question.

                                So I'm doing a gravimetric analysis task tmr where we have to look at the % of sulphate in fertilizer and compare it to the manufacturer's claim.

                                One of the steps in the experiment is to grind the fertilizer and then mix it with both HCl and distilled water. Then we boil and add barium chloride to form a precipitate.

                                I was just wondering what the role of the HCl was.

                                  sasushi
                                  A lot of times in fertilisers they also have phosphate in there. Following the solubility rules, barium phosphate is also very insoluble in water, so when you add BaCl2 to the fertiliser which may contain phosphate some Ba2(PO4)3 precipitate may form and you might erroneously include it in the mass of BaSO4 precipitate, which overestimates the sulfate content of the fertiliser. Ba2(PO4)3 is soluble in HCl so adding HCl will prevent it from precipitating such that the final precipitate is exclusively BaSO4

                                      hamna_fa
                                      You have volume and concentration of the Na2S solution so you want to convert that to mol and then you’d use molar ratios to calculate n(CdS) and hence m(CdS)

                                      Cd(NO3)2 in excess = Na2S is limiting which means the amount of Na2S present (not Cd(NO3)2) is important to know if you want to calculate how much CdS precipitate is produced

                                        Hi Billzene!

                                        For VCE purposes; do we need to know how to number carbons in a cyclic molecule?

                                        Eg. For determining if a monosaccharide is alpha or beta?

                                        Thanks in advance 🙏

                                        • G

                                          God you need to recognise the structures of alpha/beta anomers of glucose, but you don’t need to know how to name cyclical compounds except maybe benzene

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