--- title: "Less dense, not lighter: six words one chemistry paper refused - Kerfox" description: "AQA’s report on the June 2023 A-level Chemistry Paper 3 refuses six answers by name and gives its reasons. Each ruling, and the word to write instead." image: "https://www.kerfox.app/og.webp" url: "https://www.kerfox.app/blog/less-dense-not-lighter" --- [Kerfox](https://www.kerfox.app/) [THE KERFOX BLOG](https://www.kerfox.app/blog) THE MARK SCHEME WORD # Less dense, not lighter: six words one chemistry paper refused The report opens by naming the two commonest reasons students lose marks. Then it shows them, one question at a time, with the word the board wanted beside the word it got. By [Eivan Kolchin](https://www.kerfox.app/about) 7 September 2026 ## What the report says first Paper 3 is the practical paper, and its examiner report is reliably the densest reading of the three, because practical questions are answered in words and words are where marks go missing. The June 2023 report says so in its opening paragraph.[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) AQA, A-LEVEL CHEMISTRY 7405/3, JUNE 2023, GENERAL “As in previous series, the most common reasons for the failure to gain marks were lack of precision (especially when describing the steps in a calculation) and lack of clear application of chemical terminology.” That is the examiners’ own ranking of what went wrong: not the hard chemistry, and not the sums as such, but precision and terminology. The first question on the paper then illustrates it five times in a row. ## Six rulings **1. Catalyst, not proton donor.** Two thirds of students correctly named the role of the acid in an esterification as a catalyst. Some wrote oxidising agent or reducing agent, which are simply wrong. The interesting refusal is “proton donor”, which is nearly right, and the report explains exactly why nearly is not enough: it “was not allowed because, although the mode of catalytic action does involve proton donation, the proton is accepted back in a later stage of the mechanism.”[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) The acid does donate a proton. It also takes it back, and a substance that ends where it began has acted as a catalyst, which is the word that describes the whole story rather than its first step. **2. A positive answer, not a negative one.** The stem said the mixture was flammable, and most students took the hint and named a water bath or an electric heater. Some wrote that you should not use a Bunsen burner. The report is blunt: “Note that a positive answer is needed so ‘not with a Bunsen burner’ did not score.”[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) Saying what you would not do names no method, and the mark was for the method. **3. Immiscible, not a difference in density.** Only a quarter of students scored both marks on why two layers form. Many, the report says, thought “that a difference in density alone accounts for the formation of two layers. The key factor is that the organic and aqueous materials are immiscible.”[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) Density decides which layer is on top. Immiscibility is why there are two layers at all. Half the mechanism is half the marks. **4. Less dense, not lighter.** And then, in the same sentence, the ruling this post is named for. The ethyl ethanoate forms the upper layer because it is “less dense (NOT lighter) than the aqueous layer”.[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) The capitals are the board’s. Lighter is a claim about mass, and a large enough volume of ethyl ethanoate is heavier than a small volume of water and still floats on it. The layers are decided by density, so the word is density. Two layers in a separating funnel. There are two because the liquids are immiscible; the organic one is on top because it is less dense. Lighter is struck through because that is what the board did. **5. Drying agent, not dehydration.** Anhydrous calcium chloride is added to a wet organic product as a drying agent, and 64% of students said so. “A significant minority referred to ‘dehydration’ which is not an acceptable answer due to the alternate meanings of that term in Chemistry.”[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) In chemistry, dehydration is a reaction: an alcohol losing water to become an alkene, which happens to be the subject of the very next question. A drying agent removes water from a mixture. A dehydrating agent removes it from a molecule. The word points at the wrong one. **6. Displayed means displayed.** In question 02.1 a displayed formula was asked for and only 36% gave one; the commonest reason for the lost mark was “that the OH group was not displayed”. The mirror image follows one part later, in a skeletal formula, where “the OH group must NOT be displayed”.[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) The two words name two conventions, and the mark is for using the one that was asked for. ## What precision means to an examiner None of the six refused answers is chemically illiterate. A proton donor is a real thing the acid does. A negative answer shows the student knew about flammability. Density is genuinely involved in the layers. Lighter is what a person would say. Dehydration is a chemistry word. An OH group written as a group is how every textbook writes it in running text. What they have in common is that each one stops short of the thing the mark is for, or points at something next to it. The examiner has a list of statements they may credit, and the question they ask of a script is not “does this student understand?” but “is the creditable statement on the page?”. Precision, in the report’s sense, is the habit of writing the statement the mark is for rather than a true statement in its neighbourhood. The report offers one more example of that habit in question 05.2, about polarity, where “many answers referred to differences in electronegativity without explicitly stating which atoms the difference was between or which way round the difference was”.[1](https://www.kerfox.app/blog/less-dense-not-lighter#source-1) Electronegativity is a property of an atom. A difference has two ends. An answer that does not say which two atoms and which way round has described the idea and left the chemistry out. ## What to write instead - When a question asks for a role, name the role that describes the whole story: `catalyst`, not the first thing the substance does. - When a question asks how, say what you would do, never what you would avoid. A method is a positive statement. - When two liquids separate, give both halves: they are `immiscible`, so there are two layers, and the upper one is `less dense`. - Drying is what you do to a wet product. `Drying agent`. Keep “dehydration” for the reaction it names. - A `displayed` formula shows every atom and every bond, including the O to H. A skeletal one shows neither. - Any time you write “difference in electronegativity”, follow it with the two atoms and which is greater. ## Credited and refused All from the one report, all AQA, all June 2023. Where the report gave a reason it is the reason below. | Credited | Refused | Why the line is there | | catalyst | proton donor; oxidising agent; reducing agent | The acid donates a proton and accepts it back later in the mechanism, so it has acted as a catalyst overall. Q01.1. | | a water bath; an electric heater | “not with a Bunsen burner” | A positive answer is needed. Naming what you would not do names no method. Q01.2. | | immiscible | a difference in density (alone) | Density decides which layer is on top; immiscibility is why there are two. Q01.5. | | less dense | lighter | The board’s own capitals: “less dense (NOT lighter)”. Lighter is about mass; the layers are about density. Q01.5. | | drying agent | dehydration | Dehydration names a reaction that removes water from a molecule. Q01.6. | | every bond shown (displayed); no OH shown (skeletal) | OH as a group in a displayed formula | Two conventions; the mark is for the one asked for. Q02.1 and Q02.2. | ## Sources 1. AQA (2023). Report on the Examination, A-level Chemistry 7405/3, June 2023. [filestore.aqa.org.uk/…/AQA-74053-WRE-JUN23.PDF](https://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2023/june/AQA-74053-WRE-JUN23.PDF)Opens by naming lack of precision and "lack of clear application of chemical terminology" as the commonest reasons for lost marks. Q01.1: "proton donor" refused because the proton is accepted back later in the mechanism. Q01.2: a positive answer is needed, so "not with a Bunsen burner" scores nothing. Q01.5: two layers form because the liquids are immiscible, and the upper one is "less dense (NOT lighter)". Q01.6: "dehydration" refused for a drying agent because the term means something else in chemistry. ## Read next - [ THE MARK SCHEME WORD ### Electron pair donor: the word “pair” is the mark AQA’s June 2018 Chemistry Paper 2 report says students who called a nucleophile an electron donor lost the mark. The missing word, and what else was refused. 7 September 2026 ](https://www.kerfox.app/blog/electron-pair-donor) - [ THE MARK SCHEME WORD ### Active site, binding site or receptor: the word AQA is waiting for An enzyme has an active site. An antibody has a binding site. A cell has a receptor. AQA’s examiner reports name the wrong one, four times, on three papers. 7 September 2026 ](https://www.kerfox.app/blog/active-site-is-not-the-answer) - [ HOW THE PAPER IS MARKED ### How a six-mark chemistry question is actually marked A levels-of-response answer is marked twice: for its shape, then for its content. What AQA’s examiners said a Level 3 answer looks like, and what holds it back. 7 September 2026 ](https://www.kerfox.app/blog/how-a-six-marker-is-marked) WHERE THIS IS BUILT IN Kerfox marks written answers against the board’s own words, so the word a mark scheme refuses is the word the app refuses too, with the reason. It is free, and it is in closed testing. [Join the waitlist](https://www.kerfox.app/waitlist)