Thursday, 20 August 2015

Mole Concept Quiz 1 - Work Solution

This is a step- by- step guide to the mole concept quiz which was recently posted. I am going through this question as I get some feedback from my students that this question is slightly different from the questions they are used to. In fact for O levels, this question is not common, but all the basics required are in the syllabus. Hence, I highly recommend that you try it, to test how good you are at applying what you have learnt.

In order to be able to do this question, you will need to know these three chapters relatively well. Click on the links below to revise them: 



In this video, I will go through, step by step how to tackle such questions. For mole concept calculation questions, typical solving techniques involve:

  • writing the chemical equations for the reactions involve
  • determine what are the numerical information provided (since this is a calculation questions, you would need the numbers)
  • and finally, solve the questions by performing calculations!

Once you have watched this video, you may like to attempt more questions on mole concept to reinforce your understanding.


Saturday, 15 August 2015

Phase 1 of Secondary School Chemistry

After a month of working on this blog, I would say that phase 1 of Secondary School Chemistry is completed!

https://pixabay.com/en/pieces-of-the-puzzle-items-form-592820/


This blog now comes with the Notes and the Question Bank section. The notes section provides a simple summary of what you need to know for that topic The question bank consist of short quizzes and tests. All the questions are grouped by topics, and answers are provided for all questions.

I will be consistently adding more questions to the Secondary School Chemistry, so stay tuned!

https://pixabay.com/en/blogging-blogger-office-business-336376/

Meanwhile, I will also be adding a new subject blog in the world wide web! I'll let you know when it's on board.

Enjoy!

Tuesday, 11 August 2015

Periodicity - Test 1

This test is on periodicity. You may like to revise this chapter first before attempting the questions. 






The total score for this test is 10 marks. You should complete the test in 10 minutes.

Section A: Multiple Choice Questions (5 marks)

1. The symbol of an atom of element X may be written as 

To which Group does element X belong?

A. 0 
B. II
C. V
D. VII

2. When potassium is added to cold water, the reaction occurs explosively. 

When metal Y is added to cold water, the reaction occurs even more explosively.

Which of the following could Y be?

A.  calcium
B.  sodium
C.  rubidium
D. magnesium

3. The colour intensity of Group VII elements decreases down the Group.

What could be the colour of Astatine?

A. reddish brown
B. black
C. purple
D. white

4. Element W exists as a macromolecule.

To which Group does element W belong?

A. 0
B.  I
C. IV
D. VII

5. Caesium is in Group I of the periodic table.

What is the charge of caesium ion?

A. +1
B. +2
C. +3
D. +4

Section B: Open- ended questions (5 marks)
1. Elements W, X, Y and Z have the following proton numbers.


Element
Proton number
W
8
X
10
Y
12
Z
16


(a) Which elements are in the same group in the periodic table?
(b) Name any two elements that can combine together to form ionic compounds? Write the formula of the compound.
(c) Which element exist as atoms?

2. Chlorine is bubbled into a test tube containing to aqueous sodium bromide. 
(a) Describe the observations.
(b) Write an ionic equation for the reaction.

Monday, 10 August 2015

Particulate Theory of Matter - Quiz 1

This quiz on particulate theory of matter. You may like to revise this chapter before attempting the question. 


https://pixabay.com/en/water-splash-photography-lemon-bar-747618/



1.  A solid X is heated. The change is temperature with time is recorded in the graph below. At which point in time does X exist as a mixture of liquid and gas?


Separation Method and Testing for Purity - Quiz 1

This quiz on separation method and testing for purity. You may like to revise these chapters first before attempting the question. 
https://pixabay.com/en/destille-distill-chemistry-160/



1.  Which method could be used to obtain pure water from sea water.
A. fractional distillation
B. distillation
C. evaporation
D. crystallization


Air and Atmosphere - Quiz 1

This quiz on air and atmosphere. You may like to revise this chapter first before attempting the question. 


https://pixabay.com/en/oxygen-pressure-regulator-oxygen-lax-502887/

1.  Which gas can be produced by incomplete combustion of hydrocarbons?
A. sulfur dioxide
B. nitrogen dioxide
C. hydrogen chloride
D. carbon monoxide


Redox Reactions - Quiz 1

This quiz on redox reactionsYou may like to revise this chapter first before attempting the question. 

1.  Which reaction below is not a redox reaction?

A.  Zn + 2HCl ---> ZnCl2 + H2
B.  Ba(NO3)2 + Na2SO4 ---> BaSO4 + 2NaNO3
C.  I2 + 2Na2S2O3 ---> 2NaI + Na2S4O6
D.  CH3CH2OH + O2 ---> CH3COOH + H2O






Related Google Apps
-  Redox

Electrolysis and Electrochemical Cells - Test 1

This test is on electrolysis and electrochemical cells. You may like to revise this chapter first before attempting the questions. 


https://pixabay.com/en/experiment-electro-chemical-35715/



The total score for this test is 10 marks. You should complete the test in 10 minutes.

Section A: Multiple Choice Questions (5 marks)

1. Which of the following cannot conduct electricity.
A. copper
B. aqueous copper (II) sulfate
C. dilute hydrochloric acid
D. ethanol 

2. Inert electrodes are used in the electrolysis of the following aqueous solution. Which will not produce hydrogen gas at the negative electrode?
A. aqueous sodium hydroxide
B. aqueous copper (II) sulfate
C. aqueous iron (II) sulfate
D. dilute hydrochloric acid

3. In an electrolysis experiment, the same amount of charge deposited 32.4 g of silver and 5.9 g of nickel. The charge on the silver ion was 1+.

What was the charge on the nickel ion?
A. 1+ 
B. 2+
C. 3+
D. 4+ 

4. Inert electrodes are used in the electrolysis of 204 g of molten aluminium oxide. What is the mass of aluminium and oxygen collected?

mass of aluminium (g)
mass of oxygen (g)
A.
82
122
B.
131
77
C.
108
96
D.
75
133

5. Concentrated sodium chloride solution is electrolysed using inert electrodes. What is the ratio of the volume of gases formed at the anode to the cathode?
A. 1:1
B. 2:1
C. 1:2
D. 2:3

Section B: Open- ended questions (5 marks)
1. A student sets up an experiment to electroplate an object with copper.



(a) Show in the diagram, the direction of the flow of electrons in the external circuit.
[1 mark]
(b) Write equations, with state symbols, to show the reactions that happen at the cathode and the anode.
[2 marks]
(c) If the silver rod is replaced by graphite rod. Instead, bubbles of gases are produced at the cathode.  

(i) Suggest an identity for the gas produced at the cathode.
[1 mark]
(ii) Suggest how the concentration of copper (II) ions in the solution changes with time.
[1 mark]



Sunday, 9 August 2015

Metals and Rusting - Quiz 1

This test is on metals and rusting. You may like to revise these chapter first before attempting the questions.

1. When metal X is added to aqueous copper (II) sulfate, a blue precipitate is formed. Which of the following could X be?
A. sodium
B. magnesium
C. zinc
D. copper


Metals and Rusting - Test 1

This test is on metals and rusting. You may like to revise this chapter first before attempting the questions. 


https://pixabay.com/en/screw-mother-metal-iron-thread-272861/



The total score for this test is 10 marks. You should complete the test in 10 minutes.

Section A: Multiple Choice Questions (5 marks)

1. When hot hydrogen is passed over a black solid, the solid turned reddish brown. Which of the following could the black solid be?
A. copper (II) oxide
B. zinc oxide
C. magnesium oxide
D. calcium oxide

2. Underground steel pipes can be protected from rusting by sacrificial protection. Which element below is most suitable to be used as the sacrificial substance.
A. magnesium
B. carbon
C. lead
D. copper

3. An experiment is carried out to find the order of reactivity of some metals. Three metals, X, Y and Z are placed in separate solutions containing metal ions X, Y and Z.

The results from the experiment are shown below.
metal ion
aqueous metal ion
X ion
Y ion
Z ion
X
-
No reaction observed.
No reaction observed.
Y
Reaction observed.
-
Reaction observed.
Z
Reaction observed.
No reaction observed.
-
Arrange the metals according to their order of reactivity, starting from the most reactive.

A.   X, Y, Z
B.   Y, Z, X
C.   X, Z, Y
D.   Y, X, Z

4. Which statement about metals is incorrect?
A. Metals can conduct electricity in the solid states.
B. Layers of atoms in pure metal can slide past one another easily.
C. Metallic bonding consist of positive ions in a sea of mobile electrons.
D. All metals react with water to form hydrogen.

5. Which of the reaction(s) will produce a gas?
reaction 1: sodium with water
reaction 2: heating calcium carbonate
reaction 3: copper with hydrochloric acid

A. 1, 2 and 3.
B. 1 and 2 only.
C. 1 and 3 only.
D. 2 only.

Section B: Open- ended questions (5 marks)
1. Which of the structure (X or Y) best represents

a. (i) solid pure metal
   (ii) solid alloy
[2 marks]

b. Explain why is pure iron is seldom used industrially. [2]

c. Name an alloy of iron that does not rust. [1]


Saturday, 1 August 2015

Writing Chemical and Ionic Equations - Test 1

This test is on writing chemical and ionic equations. You may like to revise this chapter first before attempting the question. 


https://pixabay.com/en/writing-cursive-pen-math-calculus-104091/

The total score for this test is 10 marks. You should complete the test in 10 minutes.

1. Write balanced chemical and ionic equations for the following reactions. Include state symbols in your answer.
a) zinc + dilute hydrochloric acid ---> zinc chloride + hydrogen
b) calcium carbonate + dilute nitric acid ---> calcium nitrate + carbon dioxide + water
c) aqueous sodium hydroxide + dilute sulfuric acid ---> sodium sulfate + water
d) aqueous sodium hydroxide + aqueous copper(II) sulfate ---> copper (II) hydroxide + sodium sulfate
e) aqueous sulfuric acid + aqueous barium nitrate ---> barium sulfate + nitric acid

Oxides - Quiz 1

This quiz on oxidesYou may like to revise this chapter first before attempting the question. 

1.  Which compound dissolves in both dilute hydrochloric acid and aqueous sodium hydroxide?

A. zinc oxide
B. magnesium oxide
C. carbon monoxide
D. carbon dioxide


Rate of reaction - Test 1

This test is on rate of reactionYou may like to revise this chapter first before attempting the question. 

The total score for this test is 10 marks. You should complete the test in 10 minutes.

Open Ended Questions [10 marks]
Experiment 1 was carried out to investigate the rate of reaction between 0.2 g of magnesium ribbon and 25 cm3 of 0.1 mol/dm3 of hydrochloric acid, at 25 oC. x cm3 of hydrogen (measured at room temperature and pressure) was produced.




a) Write a balanced equation for the reaction between magnesium and hydrochloric acid. Include state symbols in your answer.
[2 marks]
b) Determine the value of x.  
[3 marks]
c) Sketch on the same graph the volume of oxygen produced with time, when 0.2 g of magnesium ribbon is added to 12.5 cm3 of 0.2 mol/dm3 of hydrochloric acid, at 25 oC.
Label this graph experiment 2.
[1 mark]
d) Another experiment was carried out using 0.2 g of magnesium ribbon and  25 cm3 of 0.1 mol/dm3 of ethanoic acid, 25 oC. 

i) Sketch on the same graph the volume of oxygen produced with time for this experiment. 
Label this graph experiment 3.
[1 mark]


ii) Explain the difference in the rate of reaction between experiment 1 and 3. 
[ 1 mark]

e) A fourth experiment was conducted using 0.2 g of magnesium ribbon and 25 cm3 of 0.1 mol/dm3 of sulfuric acid, at 25 oC. 

i) Sketch on the same graph the volume of oxygen produced with time for this experiment. Label this graph experiment 4. 
[ 1 mark]
ii) Explain the difference in the rate of reaction between experiment 1 and 4. 
[ 1 mark]


Endothermic and Exothermic Reactions - Quiz 1

This quiz on endothermic and exothermic reactions. You may like to revise this chapter first before attempting the question. 

https://pixabay.com/en/temperature-warm-hot-cold-weather-157127/

1.  Which of the following processes is/ are exothermic?

Process 1: Cl2 (g) ---> 2 Cl (g)
Process 2: C (s) + O2 (g) ---> CO2 (g)
Process 3: H2O (s) ---> H2O (l)

A. 1 only
B. 2 only
C. 1 and 2 only
D. 2 and 3 only


Chemical Bonding - Test 1

This test is on chemical bonding. You may like to revise the chapter first before attempting the question. There are a few posts that I have created on this chapter:

The total score for this test is 10 marks. You should complete the test in 10 minutes.

https://pixabay.com/en/hourglass-timer-sand-clock-23654/

Section A: Multiple Choice (5 marks)
1. A compound X contains bromine and one other element. 

Which property of X indicates that the bonds in X are ionic?
A. It conducts electricity when molten.
B. It does not conduct electricity in the solid state.
C. It is insoluble in water.
D. It is gaseous at room temperature.

2. Which solid does not contain covalent bonds?
A. graphite
B. iodine
C. calcium carbonate
D. copper

3. Which of the following ions have the same number of electrons as neon atom, which has an atomic number of 10.
A. sodium
B. lithium
C. chloride
D. bromide

4. In which molecules are all the outer electrons of the atoms involved in bonding?
A. HCl
B. C2H4
C. H2O
D. F2

5. The following shows the structure of a molecule, which is made up of elements Y and Z.




Which of the following could X and Y be?

element Y
element Z
A
chlorine
nitrogen
B
hydrogen
phosphorus
C
sodium
nitrogen
D
lithium
phosphorus

Section B: Open- ended questions (5 marks)
1. Particle Z has 17 protons, 18 electrons and 18 neutrons.
i) Is particle Z a positive or negative ion?
ii) Which group in the Periodic Table does element Z belong to?
iii) Predict the type of bonding particle Z forms with sodium.
iv) Suggest the formula of the compound formed between an atom of Z and carbon.
v) By means of a dot- and- cross diagram, draw the structure of the compound formed between atom(s) Z and carbon. Show only the valence electrons.



Answers
https://pixabay.com/en/cat-angry-telephone-talk-answer-47514/
Section A:
1) A
2) D
3) A
4) B
5) B

Section B:
1 i) negative ion
ii) Group VII
iii) ionic bonding
iv) CZ4
v)

















Organic Chemistry - Test 1

This test is on organic chemistry. You may like to revise the chapter on alkanes and alkenes, as well as the chapter on alcohols, carboxylic acids, esters and macromolecules first before attempting the question. 

The total score for this test is 10 marks. You should complete the test in 10 minutes.

https://pixabay.com/en/hourglass-timer-sand-clock-23654/

Section A: Multiple Choice (3 marks)
1) When one mole of octane (C8H18) is cracked, it produces one mole of butane and one mole of compound X.


Determine compound X.


A. propane
B. propene
C. butane
D. butene

2) 20 cm3 of hydrocarbon Y was completely burnt in 200 cm3 of oxygen (both volumes measured at room temperature and pressure). The residual gas was then cooled to room temperature and pressure, and the volume was found to be 150 cm3. When this gas was passed through aqueous sodium hydroxide, the volume decreased by 80 cm3.

Which of the following could X be?

A. propane
B. propene
C. butane
D. butene

3) Ethanol reacts with hot acidified potassium manganate (VII) to form compound B. 

Which of the following is a property of compound B?
A. Compound B reacts with sodium carbonate to give carbon dioxide
B. Compound B reacts with sodium to give hydrogen 
C. Compound B undergoes esterification with an alcohol.
D. Compound B decolorizes aqueous bromine


Section B: Open- ended questions (6 marks)
1) 100g of ethene polymerizes to form 80 g of poly(ethene). Determine the percentage yield of poly(ethene). 
[1 mark]

2) Describe a simple test to distinguish between hexane and hexene. 
[2 marks]

3) A sweet smelling compound X is formed when ethanol reacts with methanoic acid in the presence of a catalyst.
i) Name the catalyst. 
ii) Draw the structure of compound X.
iii) Name compound X.
[4 marks]



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