金科 Perfect Ten Tuition Centre at Desa Cemerlang

07/11/2021

什么是 Salt preparation？
什么重点和怎么准备这一课？

看以下 video!!! 🤩🤩🤩

SPM Form 4 Chapter 6.3 Acid & Bases - Salt Preparation 中文解说 -level : https://forms.gle/eShN6C6Tg1FEqEt18*************...

04/11/2021

Lesson module, past year and tutorials for Mathematics T Term 3 printed and ready to collect! Let's go! 🤩🤩

04/11/2021

Let us take a look at how SPM Acid/Bases questions can be designed to trick you all! 🤯🤯🤯

Answer attached! 👇👇👇

今天我们来看看考试能如何问关于 acid bases 的 reaction 的问题？他们又能如何挖坑给你们跳？🤯

明白了题目，那有需要如何回答才能拿分？
题目来自： https://youtu.be/D6D-Qs9jRjg
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Q1
首先你们必须要熟悉 acid 和 base 的各个 reactions！这一题是关于 base + metal carbonate (metal salt)，是一个 displacement reaction

Ans: 2 KOH + Na2CO3 -> K2CO3 + 2 NaOH
(Unlike acid, when KOH (the alkali/base) reacts with Na2CO3, it is a displacement reaction.)

Q2
Ans:
NO. because ONLY acid reacts with metal carbonate to give salt+CO2+H2O.
When base/alkali reacts with metal carbonate, it is a displacement reaction?

Q3
切记！只要题目要求你们改变 concentration，通常都会是 dilution reaction，把 concentration 从 很浓 变 比较稀，你要应用一下这个 equation
M1V1 = M2V2
而 V 指的是容器里面 总共 的液体！

Ans:
M1V1 = M2V2
(3.0 mol/dm3) x (20 cm3) = (1.0 mol/dm3) x V2
V2 = 60cm3

However, remember 60cm3 is the TOTAL VOLUME, hence the water added is 60 - 20 cm3 (originally present) = 40 cm3

Water added = 40cm3

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有兴趣上线上补习班的同学能看以下 👇👇👇

[👨‍🔬 Google form for online lessons] - https://forms.gle/eShN6C6Tg1FEqEt18

[💬 WHATSAPP] - https://wa.link/v7ge30

[📘 FACEBOOK] - https://www.facebook.com/Chemistry.with.MrTen/
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[📺 YOUTUBE] - https://www.youtube.com/channel/UCLegXvkspKdlZ9DahKIFrfA

03/11/2021

We are happy to welcome back our fellow STPM Term 3 students and prospective new students for the final semester in your studies. Let's make it the best one you ever had! 🤩🤩We thank you all for your continuous support to Perfect Ten centre 🥰
Here is the schedule for Term 3 classes.

31/10/2021

今天来理解与明白 Form 4 Acid 和 base 会怎么 react！
还有关于 concentration 的重点！

阅读重点，轻松应对考试！👇👇👇

SPM Form 4 Chapter 6.2 Acid & Bases - Reactions & Concentrations 中文解说 -level : https://forms.gle/eShN6C6Tg1FEqEt18***...

27/10/2021

acid and bases 究竟会有什么挑战智商的问题？

看以下！（附有答案）👇👇👇

今天我们来看看 考试能怎么问关于 acid and bases 和 pH 的问题？🤯

明白了题目，那有需要如何回答才能拿分？
题目来自： https://youtu.be/04u_BjVcrHo
================================================
Q1
对于这一课，你们必须理解 acid 和 base 的 definition

Ans: A base can be an insoluble or soluble base, which the soluble base is known as alkali.
(The example of alkalis are SPA - Sodium hydroxide, Potassium hydroxide, Ammonium hydroxide)

Q2
对于这一点，你必须明白 strong 和 weak acid 存粹告诉你的是他们在水里面的状态。pH 的高低是完全取决于 H+ 的浓度！

Ans: This statement is wrong because pH is solely depending on the concentration of H+. There might be cases where you have very low concentration of strong acid and high concentration of weak acid!

Q3
（题目有更正，是 0.1 mol/dm3 的 H2SO4）
首先你们必须明白 H2SO4 会怎么分解，才能知道 H+ 的 concentration

Ans:
H2SO4 -> 2 H+ + SO4^2-
0.1 mol/dm3 H2SO4 will produce 2 x 0.1 mol/dm3 of H+

[H+] = 0.2 mol/dm3

pH = - lg[H+]
pH = - lg (0.2)
pH = 0.70

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有兴趣上线上补习班的同学能看以下 👇👇👇

[👨‍🔬 Google form for online lessons] - https://forms.gle/eShN6C6Tg1FEqEt18

[💬 WHATSAPP to get free notes!] - https://wa.link/v7ge30

[📘 FACEBOOK] - https://www.facebook.com/Chemistry.with.MrTen/
[📷 INSTAGRAM] - https://www.instagram.com/chemistry.with.mrten/
[📺 YOUTUBE] - https://www.youtube.com/channel/UCLegXvkspKdlZ9DahKIFrfA

24/10/2021

今天来理解与明白 Form 4 Acid and Bases！

阅读重点，轻松应对考试！👇👇👇

SPM Form 4 Chapter 6.1 Periodicity - Group 1 & Group 17 中文解说 -level : https://forms.gle/eShN6C6Tg1FEqEt18************...

20/10/2021

Let's have a look at exam questions that might come out for SPM Form 4 - Period 3 compounds and transition metals!

Below with Answers indicated! 🤩

今天我们来看看 考试能怎么问关于 Period 3 compounds 和 transition metals 的问题？🤯
明白了题目，那有需要如何回答才能拿分？

题目来自： https://youtu.be/FlnBbXdOJUM
================================================
Q1 关于这道题目，你们必须记得因为是同个period，他们都有相同数目的 shell，可是 proton number 不一样，所以 force of attraction 也会随着 proton number 而改变，从而影响 size

Ans: Across the period, atomic size decreases [1]. Although period 3 elements have the same number of shells [2], but there is an increase in proton number across the period [3], which means force of attraction from proton to valence electrons increase across the period [4]. Hence, the atomic size decreases across the period.

Q2 关于 melting/boiling point，我们必须搞清楚 period 3 oxides 的 bond！

Ans: Across the period, the melting/boiling point increase from Na2O to Al2O3 because they are ionic compounds [1] which are bonded by strong electrostatic forces [2]. The melting/boiling point then increase drastically for SiO2 as SiO2 is giant covalent [3] which is bonded by strong covalent bond [4]. From group 5 onwards, melting/boiling point drops abruptly as they are the simple covalent compounds [5] which are bonded by weak intermolecular forces [6].

Q3 这题其实很简单，只需要背起来视频提到的 4 个 properties！

Ans: The 4 chemical properties of transition metals are...
They can form coloured compounds [1]
They have more than one oxidation numbers [2]
They can be used as catalyst [3]
They can form complex ions [4]

Q4 对于这一题，我们必须清楚知道 transition metals 和 group 1 metals 的 physical properties

Ans: Group 1 metals usually have low density [1] and low melting/boiling points [2].
While transition metals have high density [3] and high melting/boiling points [4].

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有兴趣上线上补习班的同学能看以下 👇👇👇

[👨‍🔬 Google form for online lessons] - https://forms.gle/eShN6C6Tg1FEqEt18

[💬 WHATSAPP to get free notes!] - https://wa.link/v7ge30

[📘 FACEBOOK] - https://www.facebook.com/Chemistry.with.MrTen/
[📷 INSTAGRAM] - https://www.instagram.com/chemistry.with.mrten/
[📺 YOUTUBE] - https://www.youtube.com/channel/UCLegXvkspKdlZ9DahKIFrfA

16/10/2021

这个星期我们会集中在 Form 4 第 5 课的最后一支影片了！

让你们轻松学习化学！

SPM Form 4 Chapter 5.2 Periodicity - Group 1 & Group 17 中文解说 -level : https://forms.gle/eShN6C6Tg1FEqEt18************...

13/10/2021

Interesting questions for Periodicity to try!

QnA attached! 👇👇👇

Periodicity 里会有什么关于 Group 1 和 17 的问题？🤯
如果需要，考试又会如何刁难你的理解能力呢？😰

题目来自： https://youtu.be/zb8BjCDaMP8
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Q1
首先，你们必须知道 Group 17 的 chemical properties。当 Halogen (X2) react with water，你会得到这个 reaction：
X2 + H2O -> HX + HOX

Ans:
When Br2 dissolves in water, the chemical reaction is:
Br2 + H2O -> HBr + HOBr
When tested with blue litmus paper, the colour will remain as blue and decolourise after that.

Q2
在这里，你必须知道每个 group 往下走，他的size 都会变大，proton 和 electron 之间的 force of attraction 一定是跌的。之后就取决于 group 1 和 17 需要 拿 还是 丢 electron 了

Ans:
When going down Group 1, the atomic size increases [1], which means the force of attraction from proton on the valence electrons will decrease [2]. Hence, when going down the group, it will be easier for Group 1 element to donate their valence electron [3], and the reactivity increases [4].

When going down Group 17, the atomic size increases [5], which means the force of attraction from proton on the valence electrons will decrease [6]. Hence, when going down the group, it will be more difficult for Group 17 halogens to gain electron into their valence shell [7], and the reactivity decreases [8].

Q3
这个问题其实要知道的是，melting boiling points 需要使用 bonding 来做解释。metal 的 bond 就是 metallic bond！

Ans:
Metals are bonded by metallic bond [1], which the layers of cations are surrounded by the sea of delocalised electrons [2]. When going down the group (from period 2 to period 5), size of cations increase [3], which means the the force of attraction between the proton and delocalised electrons decrease [4]. Hence, for metal in the same group, the melting point of a period 5 metal will be lower than a period 2 metal [5].

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有兴趣上线上补习班的同学能看以下 👇👇👇

[👨‍🔬 Google form for online lessons] - https://forms.gle/eShN6C6Tg1FEqEt18
[💬 WHATSAPP to get free notes!] - https://wa.link/v7ge30
[📘 FACEBOOK] - https://www.facebook.com/Chemistry.with.MrTen/
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[📺 YOUTUBE] - https://www.youtube.com/channel/UCLegXvkspKdlZ9DahKIFrfA

10/10/2021

这一期我们来看看 SPM 里的...

Group 1 和 Group 17！

学习每个重点！📝
学习作答技巧！🧠
轻松搞垮化学！🎉

SPM Form 4 Chapter 5.2 Periodicity - Group 1 & Group 17 中文解说 -level : https://forms.gle/eShN6C6Tg1FEqEt18************...

07/10/2021

What kind of question will they ask for Group 18 in exam???

See below for the questions and also answers attached! 👇👇👇

究竟 Periodicity 关于 Group 18 有什么重点？
考试会怎么问？？？

题目来自：https://youtu.be/jwJ91fD7kSE
================================================
Q1
首先，重复之前教过的，只要是解释 melting/boiling point，你就必须使用 bonding 来解释！
这个情况需要理解 group 18 是 non-metal

Ans:
Group 18 noble gases are non-metal. Hence they are bonded by weak Van der Waals forces.

When going down group 18, as size increases [1], the surface area in contact between the atoms increase [2]. Hence, the weak Van der Waals forces between the atoms will increase [3], resulting in an increase in melting/boiling point [4]

Q2
在这里，你必须知道 group 18 compound 是 noble gas，是不 reactive 的！

Ans: Ne is from Group 18, and it has a full octet structure [1] which means it is stable and will not share / donate / gain electrons [2]. Hence Ne will not react with Na. [3]

===============================================
有兴趣上线上补习班的同学能看以下 👇👇👇

[👨‍🔬 Google form for online lessons] - https://forms.gle/eShN6C6Tg1FEqEt18

[💬 WHATSAPP to get free notes!] - https://wa.link/v7ge30
[📘 FACEBOOK] - https://www.facebook.com/Chemistry.with.MrTen/
[📷 INSTAGRAM] - https://www.instagram.com/chemistry.with.mrten/
[📺 YOUTUBE] - https://www.youtube.com/channel/UCLegXvkspKdlZ9DahKIFrfA