2026 Chemistry Nat5 Scotland Section 1 Multiple Choice Walkthrough and comments

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[00:00:00]Okay, this is uh paper one from the 2026 chemistry exam not five and uh I've got a document here I think you should read.

[00:00:07]I'm just going to pass through it. But there's a quick disclaimer it took me a couple of hours to do the the the exam.

[00:00:12]I I do it as a almost as a uh um in exam conditions. I'm not sure I'm 100% correct in everything so don't uh none of this is guaranteeing anything. Um I'm not a marker so I can't give you decisions and things. If you spot anything that I've got wrong, let me know I'll update the errata in the description. So check the description if you think I've got something wrong in case somebody else has already spotted it and I've already updated.

[00:00:38]Uh this is about learning while the exam is fresh in your mind. It's a learning experience and um that's why I do these.

[00:00:48]Uh you'll notice that I'm not going to do higher um I don't think because higher are much higher stakes exams higher stakes exams and uh I think it's important that uh I do those really correctly which means to spend a lot more time on them. This is a learning experience. Okay, let's get on with the paper. Okay, question one.

[00:01:06]Let's get started. Question one, which of the following statements is not true when a catalyst is added to a chemical reaction? Well, uh there's a bunch of different options here and it was I thought that was quite a hard question to start with but the time taken for the reaction to finish increasing would not be a catalyst. That would be something that extends the reaction rate. So um B is the one that's correct there. Mass of product formed is the same. Catalyst has no effect and that catalyst can be recovered unchanged the rate of reaction.

[00:01:34]Increases the rate increases. That's true. Which of the following compounds has molecules that have the same shape as those found in ammonia, NH3.

[00:01:44]Okay, so what we have to do is we have to find a compound one of these compounds here that has four atoms in it because there's four atoms in NH3.

[00:01:55]>> [clears throat] >> And so we also have to find molecules.

[00:01:58]We We saw this question last year actually as well. I think it was last year, wasn't it, where they asked about this?

[00:02:02]And so, we know that sulfur dioxide is not a molecule, carbon dioxide Sorry, sulfur dioxide is a molecule, I beg your pardon.

[00:02:12]Sulfur dioxide is a molecule.

[00:02:14]Um Carbon dioxide is a molecule, but that's got three atoms. This has got three atoms. Hydrogen fluoride is a molecule and it has two [snorts] atoms. Phosphorus fluoride has four atoms cuz phosphorus has a valency of three with and fluoride has a valency of one. So, that's going to be um that's going to be P P F 3 is going to be the same NH3. So, phosphorus fluoride is your correct answer. Okay.

[00:02:47]>> [laughter] >> A graph showing the volume of hydrogen gas produced over time when 2 g of zinc lumps is added to 100 cm³ of 1 molar hydrochloric acid, right? This is uh there's a couple of little wrinkles in this exam. 1 g of zinc powder or so, we've got We've got less zinc and we've powder instead of lumps. So, the reaction's going to go faster, but it's going to produce half the amount of product. And the correct answer for that is going to be C.

[00:03:10]Uh these It's actually really quite difficult to get this lined up. So, that's the same rate as that and that.

[00:03:18]But these two rates are faster. We're presuming that the um that the the scale is the same in each place. So, that would be unfair if they didn't do that. So, correct answer was this one.

[00:03:32]So, the rate is the same as this Oh, sorry, the rate is faster than this one.

[00:03:36]Faster, that's steeper, right?

[00:03:39]So, that's We'll drag that down. So, that's This one This one here is definitely a uh a faster rate and it produces half the amount. So, there you go. Greatest number of electrons is found in 1 mole of which of the following gases? Now again, uh we need to watch out for this.

[00:03:55]A mole of the gas is going to be the molecule if there is a molecule. So that's going to be the important thing.

[00:04:01]So neon forms monoatomic gas. Fluorine is a diatomic gas. Oxygen is a diatomic gas. Nitrogen is a diatomic gas. Okay, so how many of them have the electrons?

[00:04:11]Well, the electrons is going to be the the same as the atomic number multiplied by two. Okay, they don't lose or gain any electrons here. They're just sharing them. So neon has only one atom. So it's going to be one by the number of by mole. So it's one times mole times 10 electrons for its atomic number. That gives you 10 times the mole.

[00:04:32]Uh fluorine has two times nine, which gives you 18. Oxygen is two times eight, which gives you 16. Nitrogen has two times seven, which gives you 14. So the correct answer is fluorine. Um >> [clears throat] >> you might have just The trick here is you you The trap here is you just pick neon as the highest atomic mass with the most electrons in it. But you forget that these are molecules. So it has to be fluorine. All right. Table shows some information about an ion. There it is.

[00:04:56]Electron 18, neutron 19, proton 20. The charge in this ion is Well, it has uh two more protons than it has electrons. So that's two extra positive charge uh particles in the structure. So it's going to have a two-plus charge. The difference in size between a sodium ion sodium atom, sorry, and a sodium ion is due to the mass number decreasing, the atomic number increasing.

[00:05:20]Well, the mass number doesn't decrease because uh it's it's just lost an electron. Atomic number doesn't increase because it hasn't changed its proton number. The charge of the nucleus So you can eliminate quite a few here cuz that's definitely wrong. That's definitely wrong. Charge in the nucleus is increasing. Uh that's not true either because it doesn't gain any protons.

[00:05:39]Therefore, the number of occupied energy levels is decreasing. So if you weren't sure about this, go backwards and work it out and D is your correct answer. All right. So, question seven.

[00:05:49]>> [snorts] >> Which line in the table shows the properties of a covalent network? And it's the big one. We haven't been asked about this very often, but it's the this one up here. Doesn't conduct electricity as a solid or a liquid, and it has the highest boiling point and highest melting point of anything. Right? So, it has to be A. Okay?

[00:06:07]Try melting some diamond, you'll find out all about it. The electrolyte can be made An electrolyte can be made by dissolving potassium chloride in water.

[00:06:13]Which line in the table correctly shows the solvent so- solute and solution for this process? Took me a while to figure this out, but the solution what they're meaning by solution here is electrolyte.

[00:06:22]So, the electrolyte is the solution.

[00:06:24]And then the potassium chloride is the solute.

[00:06:29]And the water is the solvent. So, the correct answer was D. Okay, lithium aluminum hydride.

[00:06:36]Um has a ground formula mass of 38 g. The percentage by mass of metal in the lithium aluminum hydride is equal to Okay, the trick here was you had to remember that lithium and aluminum are both metals. You add those two together There's only one of each of them. You add those two together for your numerator in the fraction. And um you're going to get to 34. 7 + 27 is 34, so the answer is C. Okay Okay, an acidic solution. So, it's acidic.

[00:07:04]>> [clears throat and cough] >> And a nonmetal oxides give you acidic solutions. We've only got one nonmetal oxide, so the answer is A. There you go.

[00:07:11]Um name of this compound. What's this stuff here? So, let's have a go at it.

[00:07:15]And we'll just do it from here. So, we have um 1 2 3 4 5. So, it's pentene. So, it's And our in counting is takes pre- precedence, so it's the smallest number for the in value. So, it's going to be pent 1 2 in.

[00:07:32]And then the methyl group is going to be uh on carbon four. So, it's going to be four methylpent-2-ene.

[00:07:40]So, four methylpent-2-ene is B. There it is.

[00:07:44]Which of the following is another way of representing this structure? Well, this is just a process of elimination, okay?

[00:07:48]So, what you do is you start off with CH3CH3. They're all there.

[00:07:51]And then you go CH and then CH3 in brackets. Um then you can eliminate A and you can eliminate C.

[00:07:59]Uh we're still carrying on with this.

[00:08:01]Then we get uh C H OH in brackets. CHOH in brackets is there for both of those.

[00:08:08]Uh then we get to this one, which has to be CH. And uh this one fell out cuz that's CH2. So, B is wrong and D has to be the correct answer. CHCHCH33.

[00:08:21]Okay? So, which line in the table correctly describes the changes going from cycloprop- pain to cyclobutane?

[00:08:29]Cyclopropane is uh a three-carbon cyclic alkane. And cyclobutane is a four-carbon cyclic alkane.

[00:08:43]So, um the formula mass has to increase cuz there's more carbons, right? And the strength of the molecular forces intermolecular forces increases cuz the structures are bigger. And bigger structures interact more. Uh there's not much else going on there.

[00:08:58]Intermolecular forces are still very weak in these things. So, I'm not sure cycloprop- butane is a gas.

[00:09:04]It probably is a gas, but anyway. So, which of the following is the structure of vinegar? There's actually a question in the second paper on this where they tell you ethanoic acid and they tell you they give you its formula in case you've forgotten. And if you remember that ethanoic acid was vinegar, you might have been able to go back and correct this.

[00:09:19]Uh but this is it. CH3COOH is the is ethanoic acid, which is vinegar.

[00:09:26]Metallic bonding is the electrostatic force of attraction between oppositely charged ions?

[00:09:32]Nope.

[00:09:34]Cuz that would be uh that would be ionic bonding. Two nuclei and a shared pair of electrons.

[00:09:40]Um, no.

[00:09:43]Cuz shared pairs covalent bonding, negative ions and delocalized electrons, that's just wrong because electrons wouldn't bond wouldn't be attracted to negative ions, they'd be repulsed. So, it's positive ions and delocalized electrons. You'll have just learned that. That's a nice one. That's just basic That's basic knowledge.

[00:09:59]Which of the following substances will react with an acid to produce a gas?

[00:10:03]And uh, there's a bunch of oxides here and a chloride. Magnesium chloride probably won't react with an acid at all, I'm not sure. Don't know. But anyway, metal plus acid reacts to form metal oxide plus hydrogen gas. So, magnesium will react with an acid to produce a gas. Which one of these Which of the following metals can be extracted from its ore by heating with carbon?

[00:10:23]Good grammar there, by the way. No No apostrophe in the it's. And um, sodium, calcium, magnesium. These are group one, group two metals and uh, I think they're going to require electrolysis to get them out. Iron is the one that you can extract from its ore by heating with carbon. Famously, the Iron Age. Once they discovered that, that was the Iron Age. Which of the following metals would become liquid if placed in a beaker of boiling water?

[00:10:48]You may wish to use the data book to help you. Look up the melting points of all of these things and you'll find gallium is 30° C. In fact, you can hold it in the palm of your hand and it will melt cuz you're Well, you need a good warm hand.

[00:11:01]Okay, which one of Which line in the table is correct for both the Haber and the Ostwald process? So, you've got your catalyst and your product, catalyst and product. Make sure you get them the right way around. Ostwald process is nitric acid, Haber process is ammonia.

[00:11:12]Iron and ammonia, platinum and nitric acid is your correct answer.

[00:11:17]Okay, which of the following is true for elements nitrogen, phosphorus, and potassium?

[00:11:21]You may wish to use the data book to help you. They are all nonmetals.

[00:11:25]No. They are all found in group five of the periodic table. No. They are all elements essential for healthy plant growth. Yes. They have symbols in the periodic table with the first letter of their name. No, all hands elements essential for healthy plant growth. If you've learned about your fertilizers, your teacher should have told you about NPK. Those are the three letters that you want on your fertilizer bags if they're if it's going to be any use. Anyway, the diagram shows the path of three types of radiation as they pass through an electric field. Which line in the table correctly identifies the type of radiation that follows path one, two, and three. Let's have a look at the paths. Path one is attracted to the negative plate, so it must be positive.

[00:12:01]So, that's going to be an alpha particle, which is a helium nucleus, right?

[00:12:07]Number two goes straight on, so that has to be gamma radiation because nothing affects gamma radiation. It's got no charge. And number three is attracted to the positive plate, which must mean it's an electron, oppositely charged to the positive plate. So, that's a beta particle. So, we've got alpha gamma beta is the order we're looking for. Alpha gamma beta, I got it right.

[00:12:27]Well done me. Paper. Paper factories you can use radioactive sources to measure the thickness of paper they produce.

[00:12:32]Radiation has to pass through the paper to a detector on the other side. Which line in the table describes the most suitable radioactive source for this use? I'm not sure about this one, but I'm presuming just from safety point of view, a short half-life is the correct answer. Okay, we can eliminate alpha particles because they can't get through the paper. A sheet of paper can block alpha particles. We eliminate those, then we have a choice between long and short half-life. No.

[00:12:58]Uh I'll I wouldn't go to the foot of our stairs if it turned out to be long in this. So, it could be beta and long.

[00:13:05]But I'm going for beta and short because I think short is just safer, right? In in machinery, which uh so, I don't know, short half-life would be better, maybe. But then, if you have a long half-life, your source of radiation is going to last longer and you won't have to change it so often.

[00:13:21]I'm not quite sure. That seems to me to be something of a judgment call. So, I'm not sure what they're going to put there. I would just say short because it would be safer. The materials won't hang around any longer if you have to throw them away and things like that. They wear out and you can replace them.

[00:13:35]I would go short half-life, but it's a question mark. Time taken for half of the nuclei of a particular isotope to decay.

[00:13:44]So, it's saying half the nuclei of that isotope.

[00:13:48]And it sounds kind of nearly right, right? So, what's wrong with this one?

[00:13:52]Let's have a look at the next one. Half the time.

[00:13:55]It's not half the time. It's not half the time for anything. So, it's the time taken. So, not half the time for nucleus particular. Okay. So, time taken for half the mass of a particular isotope to decay. I think it's going to have to be the nucleus. The nucleus decays, not the mass.

[00:14:11]The mass doesn't decay, right? The nucleus decays.

[00:14:15]So, I'm going to change my answer. I'm going to go for A.

[00:14:18]I think the mass The mass doesn't decay. The mass decreases.

[00:14:30]If a particular type of radiation goes, because the mass won't change if the if we have say gamma radiation.

[00:14:36]Mass won't change, will it? Cuz it's just a rearrangement. So, it has to be A, right? So, that has to be wrong. That has to be wrong. That has to be wrong.

[00:14:43]Okay, I'm going to go for A in that one.

[00:14:45]Uh here we go. Measuring cylinder and a tube. Which line in the table shows a gas that could be collected and measured using the apparatus shown?

[00:14:53]Well, the apparatus shown is a measuring cylinder, right? With a scale on it.

[00:15:00]And that's the important bit I think for this question, that scale, right?

[00:15:03]Because we have to collect and measure.

[00:15:06]That's the important thing, right? Using that apparatus.

[00:15:10]Okay?

[00:15:11]So, you might say that any gas that is denser than air, which is A and B in this case, denser than air, can be collected by this method and that's true.

[00:15:25]But we couldn't measure the colorless gas because we couldn't see it. So we wouldn't be able to measure it because we can't see it. Therefore, we have to collect the brown gas and we'll see the top of the brown gas as it floats up and we should be able to measure the edge of the brown gas when it meets the air above.

[00:15:40]And so I'm going for A on that one.

[00:15:43]Tricky question that, I think. Had to do a little thinking there, maybe.

[00:15:47]Transition metals can form large ions known as complexes. Now this is all completely uh This is tricky one. A lot of reading to do here, right? The name used for the metal in the complex changes depending on the overall charge of the complex.

[00:15:59]The table shows how the names change for the metals copper and iron in complexes with overall positive or negative charges, right? So metal in the complex copper or iron, let's look at the copper one. So if the metal in the complex is copper, if the overall charge of the complex is positive, you call it copper.

[00:16:14]Uh the ion is called copper. And if the overall charge is negative, you call it cuprate. And here we have uh iron. And iron is gets its own name if it's positive and it gets the ferrate A T E ending if it is negative. Not only that, we we use the the Latin term for both of these metals, which is kind of interesting.

[00:16:36]Right? I'm not quite sure what they do with metals that don't have Latin names, but uh somebody can tell me in the comments if they want to. All right. So uh formula for complexes X and Y are given. Here's complex X. And all we really have to do here is look at the charge, right? If the overall complex is negative, it's going to be cuprate.

[00:16:57]Right? That's copper. And the metal's copper and it's negative, so it's cuprate, right? And this is the overall charge is positive. Says overall charge is positive, positive. That has to be iron. It's going to be the name of the ion here. And uh cuprate is going to be the name of the ion there, right?

[00:17:17]These complexes. So, these are all a bit tricky, uh but anyway, I've gone for D.

[00:17:22]Uh cuprate four X and iron four Y. There you go. That's the end of the paper. Didn't need a calculator for that one. I think that's the first time in a while I've looked at a paper one for chemistry I didn't need a calculator for, but there wasn't a lot of sums in that. And what you know what that means, don't you? Means there's going to be a stack load in section two, which we're going to come to in the next video. Click a link that's going to be around there somewhere.

[00:17:52]Okay?

[00:17:53]Hope you enjoyed [clears throat] that.

[00:17:55]Again, remember if you This is National 5 is not high stakes exams. And it's nice to do well, of course, but you're in the learning process. You're learning how to do exams. It's your first It's your first time through National 5s, probably.

[00:18:09]Uh first time through formal exams, and this is a learning process. It's good to get feedback on your paper at the end of that process uh before within, you know, otherwise you have to wait 3 months, right? Okay, so hope you did well in that, and I'll see you in the next video.