Hello everyone,

Today is the last day of the 5 days Accelerated Learning Techniques seminar that i have been attending. So far so good! Event has been awesome and i have learned something new each day on getting our human mind & heart to learn things more efficiently and effectively, so that you will remember for the Rest of Your Life! Students under my wings before should know what i mean yeah?!

I look forward to 2 hours later where the event start rocking again. Meanwhile, before i leave my house, i just want to touch abit more on Organic Chemistry. I have heard from many students for the last 2 weeks that they dont really understand how to apply to the examination questions on Organic Chemistry, based on the information that were taught in school…

Let’s start the discussion by defining Hydrocarbons.

Hydrocarbons are compounds which contain Carbon and Hydrogen only. They occur abundantly in coal, petroleum and natural gas.

Saturated Hydrocarbons are those in which the combining capacity of the carbon atoms is as fully used as possible in bonding with hydrogen atoms, e.g. the alkanes.

Unsaturated Hydrocarbons are those in which the combining capacity of the Carbon atoms is not fully used. Unsaturated hydrocarbons are characterized by double or triple bonds between carbon atoms, e.g. the alkenes.

As mentioned previously, there are other compounds that contain elements like Oxygen, Nitrogen, Sulphur and other halogens (besides the Carbons and Hydrogen Atoms) –> we call these compounds collectively as Organic Compounds. There is a chance that they also have C=C double bonds.

Let’s continue by trying out one Multiple Choice Question (MCQ) as shown below:

Question:

Which compound has an additiona reaction with chlorine?

A. C2H4
B. C2H6
C. C2H5OH
D. CH3CO2H

PS: Try it out and leave your answers in the Comments Section right below this post. I encourage everyone to learn something here by participating actively by posting comments and suggested answers

Interesting questions sent in by an avid reader of SimpleChemConcepts.com.

Question:

“I want to ask if i place 1000 Chlorine atoms into water, will i obtain 1000 Hydrogen ions ? I would really appreciate if you could reply asap ! “

PS: What do you think? Write me your suggested answers at the Comment Section below.

Yesterday, we have gone through the theory of Energy Changes as well as look into one of the question of Endo/Exo reaction.

Let’s try one Multiple Choice Question (MCQ) to see if you understand it.

PS: I strongly suggest you to leave your answers in the Comment Section right below this blog. Many of you will be waiting for answers directly from me. But in this way, your learning will not be effective. As such, i am looking forward to you trying out and leaving us an aswer.

During the Intensive Revision Bootcamp, the concepts surrounding the chapter on Energy Changes (Endo/Exo) are dissected and the correct concepts are shared with the class.This chapter requires little memorization and in fact, 95% of the chapter involved the understanding of the concepts and applying them accordingly in application questions, especially for those that involves Bond-Forming & Bond-Making.

First we need to define Exothermic and Endothermic properly.

Exothermic Reactions:
Reactions that gives out heat energy to the surroundings
T of reaction mixture rises. Container feels hotter

Endothermic Reactions:
Reactions that takes in heat energy from the surroundings
Temperature of reaction mixture falls. Container feels cold.

Energy changes in reactions are caused by the making & breaking of chemical bonds

• Bond Making –> Exothermic Process

• Bond Breaking –> Endothermic Process

Tell if a Reaction is Exothermic or Endothermic by:

• Exothermic Reaction: ?H bond breaking < ?H bond making

• Endothermic Reaction: ?H bond breaking > ?H bond making

Q) Is this reaction Exothermic or Endothermic then? What is the value of Enthalpy Change?

Given:
Cl-Cl bond energy = 242 kJ/mol
H-H bond energy = 436 kJ/mol
H-Cl bond energy = 431 kJ/mol

Any takers? Write down your suggested answers in the Comment section below, and we will discuss it accordingly.

PS: Once again –> Participation is Impt! No point me showing you all the answers and working, and u dont learn.

Following is a question that was sent to me recently by a local students.
This is a question based on the Properties of Acids and is getting popular in many of the Preliminary Exams in local Top Secondary Schools.

Q )Sulphuric acid is a dibasic acid because:
A. each molecule contain 2 hydroxide ions
B. each molecule can produce 2 hydrogen ions
C. one mole of the acid contains two atoms of hydrogen that can be replaced by a metal
D. sulphuric acid can only be neutralized by 2 bases
E. sulphuric acid has the usual properties of an acid, but is also a dehydrating agent

Try working out the question before checking the answer and reasoning below. (more…)

A very interesting questions sent in by a local students.

Try this out and leave your suggested answers in the “Comments” section below this post.

Questions:
A sample of sea-water contains 0.1 g/dm^3 of bromide ions.

(i) What volume of this sea-water produces one mole of bromine molecules?

(ii) What volume of chlorine gas is required to produce 8g of bromine from this sea water?

Suggested Answers:

We have learned about balancing chemical equations as well as assigning of state symbols.

Let’s look at some examination questions and my suggested solutions.

Q) Write balanced chemical equations for each of the following reactions. Include the State Symbols.
(a) calcium + chlorine –> calcium chloride
(b) hydrogen + nitrogen –> ammonia
(c) ethane (C2H6) + oxygen –> carbon dioxide + water

My Suggested Answer:
(a) Ca(s) + Cl₂(g) –> CaCl₂(aq)

(b) 3H₂(g) + N₂(g) –> 2NH₃(g)

(c) 2C₂H₆(g) + 7O₂(g) –> 4CO₂(g) + 6H₂O(l)