2026 SCIENCE PAPER 2 PREDICTION 1 || CHEMISTRY

[00:00:01]I'm going to look at some of the prediction questions uh in this sample as you prepare for your exams.

[00:00:08]So, let's go. So, this is chemistry 5124 science.

[00:00:16]Which row describes the bouncing uh sorry, the bunching and the movement of particles in a gas?

[00:00:22]So, we have bunching and then we have uh movement there. So, which one is your answer? Before we even go anywhere, you can pause the video trying to uh When you hear bouncing, we bunching, sorry, we mean are they touching each other?

[00:00:39]Do particles in a gas touch each other?

[00:00:41]No, they don't. How do they move? They move very much freely. That makes C the correct answer. C is there, the correct answer. Which row about air, argon, and methane is correct? One thing that you need to know and understand that air is a mixture of different gases.

[00:00:58]Argon is an element. Methane is a compound. So, this is methane.

[00:01:04]Okay. Well, argon is just an element.

[00:01:07]This one is a compound.

[00:01:09]This one is an element.

[00:01:11]But, air is a mixture.

[00:01:14]Get the concept, right?

[00:01:16]So, which one is your answer? D.

[00:01:21]The nucleon number of an atom of copper is 64 and the atomic number is 29. So, it's like they give you this, they put 29 here, and they put 64 here.

[00:01:30]That's what we mean by nucleon. Nucleon number is the mass number. Okay?

[00:01:36]>> [clears throat and snorts] >> So, how many electrons are there in the atom of copper? So, the number of electrons is equal to the mass number minus the sorry is equal to the number of protons.

[00:01:49]Okay?

[00:01:50]They are the same.

[00:01:53]So, which one is your answer?

[00:01:54]A. Since they are the same.

[00:01:56]This is product number there.

[00:02:00]Which dot and cross diagram shows the outer electron configuration in a molecule of oxygen difluoride? Oxygen difluoride.

[00:02:10]So, how do we go about it? All right.

[00:02:12]So, one thing that you need to know that oxygen has got six valence electrons, isn't it? And fluorine has got seven valence electrons. So, oxygen has got six electrons in the outer shell, but fluorine has got what?

[00:02:24]Seven electrons in the outer shell.

[00:02:26]Meaning, these are all nonmetals and all nonmetals, they what? They share electrons until they are stable.

[00:02:32]Okay?

[00:02:34]So, here's what you can do. All right.

[00:02:36]Here's what you can do. Now, based on the formula, first of all, based on the formula, since oxygen needs two and fluorine needs one, the formula is OF2 as the way it is given there.

[00:02:49]So, this means we have an oxygen atom in the middle.

[00:02:54]All right. In an oxygen atom in the middle.

[00:02:56]Then surrounded by what?

[00:02:57]These.

[00:02:59]So, one is oxygen, one is fluorine, and one is fluorine.

[00:03:03]So, they just keep on sharing, sharing.

[00:03:06]Like just like that.

[00:03:08]Okay. So, let the sharing begin. So, oxygen is shares, I'll use the dot, and fluorine shares.

[00:03:15]So, >> [clears throat and cough] >> fluorine shares, I'll use the cross.

[00:03:21]Okay? How many many here? Five. How many many here? Six.

[00:03:26]5 + 2 = 7. 6 + 2 = 8. Fluorine is balanced, but remember there are two fluorines. Okay? So, let me do this.

[00:03:36]As long as oxygen donates, let me do this.

[00:03:40]Then oxygen in the middle, then a fluorine here and a fluorine here. Yeah, I number seven, I number six, I number seven. So, once oxygen in the middle has actually donated up to Okay? Oxygen can only donate two because are two fluorines. So, this one will donate and this one will donate.

[00:03:59]Now, let me do it for you like this. So, fluorine donates here, then oxygen donates there.

[00:04:06]As long as oxygen donates here, another fluorine must donate there.

[00:04:09]So, how many does oxygen remain with? Oxygen remains with what?

[00:04:15]Mhm?

[00:04:18]There are six, so it remains two.

[00:04:20]Like that.

[00:04:22]Okay?

[00:04:23]Then, what happens to this other fluorine? The other fluorine remains with what? Six. Another fluorine remains with what? With six. We can't go further than this. And the reason is simple, it's because fluorine oxygen is going to have a lone pair. That's what we call a lone pair. I mean. So, there will be two in the middle, two in the middle, just like the way this one is. Two in the middle.

[00:04:47]Are you following, okay?

[00:04:49]But, check. Here there's fluorine in the middle, but here there's oxygen in the middle.

[00:04:53]Same here, there's fluorine in the middle. Fluorine can't be in the middle.

[00:04:57]It's only oxygen can be in the middle.

[00:04:59]This makes B the correct answer.

[00:05:01]Okay?

[00:05:02]An ionic compound contains ions.

[00:05:05]Potassium ion, aluminum ion, and sulfate ion. What is the formula of the compound?

[00:05:11]Mhm. So, here's what you do. What is the formula of the compound? So, you have potassium plus aluminum ion, then plus the sulfate ion.

[00:05:24]>> [clears throat] >> Okay? Now, here's what is going to happen.

[00:05:28]It's very simple and it's straightforward. Okay?

[00:05:32]Add these charges, the positive charges.

[00:05:34]Add them.

[00:05:35]One plus what? Three. You get what?

[00:05:38]Four. So, potassium and aluminum together, it's positive what?

[00:05:45]It's positive four.

[00:05:48]There is a plus then the sulfate like that.

[00:05:53]So, when you cross multiply the two comes here, so you have potassium aluminum two, then you have the sulfate and the four there. Then from here, you can actually check to say the two can be divided by two by two. So, you have potassium aluminum sulfate and there will be two here.

[00:06:18]That's all.

[00:06:20]Student, is your answer? B.

[00:06:25]The equation for the reaction between aluminum and iron three oxide is shown.

[00:06:33]So, what is the mass of a iron produced when 16.2 g of aluminum react with excess iron? So, just use mass ratio.

[00:06:41]Use what? Mass ratio. Check, we are comparing the mass of aluminum to the mass of iron. So, compare the mass.

[00:06:50]So, you can put aluminum here.

[00:06:53]Okay, then you can put Can I raise this part so that I can solve it from here so that you understand proper what I'm what I'm trying to say?

[00:07:01]So, you can get aluminum here then you can get iron here.

[00:07:06]You compare their masses. So, we have 16 for aluminum.

[00:07:11]We don't know for iron, okay? Then just we we which other mass are we going to compare? You compare their molecular masses or their molar masses. Look for aluminum, aluminum is here.

[00:07:23]Okay?

[00:07:24]And aluminum is is like 56.

[00:07:27]No, 27.

[00:07:29]Aluminum is 27. And what is 27? Because of the two, you multiply that by two.

[00:07:34]You get what? 54.

[00:07:37]So, we put 54 here.

[00:07:40]What about for iron?

[00:07:43]Okay. What about ion?

[00:07:46]Ion is actually 56 but times two. So, what is 56 okay?

[00:07:53]Times two, you get 112 and cross multiply.

[00:07:58]So, you got 54 x is equal to 16.2 * 112. So, over 54 over 54.

[00:08:09]So, what is our x?

[00:08:11]16.2 Then you say divided by 54.

[00:08:20]I'm getting 33.6 grams.

[00:08:25]And what marks the answer?

[00:08:27]There, D.

[00:08:30]Which statement about the reaction of hydrochloric acid with aqueous sodium hydroxide is correct? Don't forget to share, subscribe, and also follow for more.

[00:08:40]Which statement about the reaction of hydrochloric acid with aqueous sodium hydroxide is correct? Remember this one is an acid. Sodium hydroxide is an alkaline.

[00:08:51]Alkaline solution, okay?

[00:08:54]So, the reaction is endothermic.

[00:08:57]Okay, and the temperature of the mixture increases. No, the reaction between hydrochloric acid and sodium is a neutralization reaction. It's not an exothermic reaction.

[00:09:07]All right? So, it's not an endothermic reaction rather.

[00:09:12]But usually neutralization reaction are always exothermic. That's true because when even when you touch the beaker where hydrochloric acid is reacting with a base, you you feel that the beaker is actually very hot.

[00:09:25]Okay, meaning they are releasing heat to the what? To the surrounding.

[00:09:29]Now, this also because they are releasing heat to the surrounding, it causes an increase in the temperature of the mixture.

[00:09:35]So, the temperature of the mixture that does what? Increases.

[00:09:39]It is exothermic, yes, and the temperature of the mixture increases, not decreases.

[00:09:44]Okay, that makes C the correct answer.

[00:09:48]Don't forget, if you want to register for online classes, you can WhatsApp us on this particular number and we can pick it up from there.