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The Global Classroom carries the unique GEMS “Dynamic” materials and assessments of Dr Sunita Gandhi, Ph.D. Cambridge University, UK. These have been tested and tried in three countries, Iceland, India and the UK, and perfected with a three year trial with over 40,000 children in India participating.

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ALL Past Questions TOPIC WISE For The Last 10-12 years

Aluminium is extracted from its chief ore, bauxite. The ore is first purified and then the metal is extracted from it by electrolytic reduction.		Marks [6]
1.	Write three balanced equations for the purification of bauxite by Hall's process.	Marks [6]
2.	Name a chemical used for dissolving aluminium oxide. In which state of sub-division is the chemical used?
3.	Write an equation for the reaction which takes place at the anode during the extraction of aluminium by the electrolytic process.
4.	Mention one reason for the use of aluminium in thermite welding.
	Choice in 2004

a With respect to the reduction of iron-ore in the blast furnace, answer the following questions:		Marks [10]
1.	Name the raw material placed in the blast furnace.
2.	Which is the actual reducing agent? Write the equation for the reduction of iron ore.
3.	What is the significance of double cup and cone arrangement ?
4.	What is the composition of the existing furnace gases?
b Compare the properties of a typical metal and a non-metal on the basis of the following:
1.	Electronic configuration
2.	Nature of the oxides.
3.	Oxidising or reducing action
4.	Conductivity of heat and electricity.
	Choice in 2003

1.	Name the ore of zinc containing its sulphide.	Marks [10]
2.	In the process of extracting zinc, the above named ore is roasted. Write the equation for the reaction which takes place when the sulphide ore is roasted.
3.	Name the substance used to reduce the roasted ore. Write the equation for the reaction.
4.	'Iron is removed from a blast furnace as a liquid'. State how zinc leaves a furnace.
b	Write the equations for the reaction of zinc with each of the following :-
1.	Sodium hydroxide solution
2.	Dilute sulphuric acid
3.	Copper sulphate solution.
c	(1.) To protect iron from rusting it is coated with a thin layer of zinc. Name this process.
	(2.) Name a non-metal that has a metalic lustre and sublimes on heating.
	Choice in 2004

1.	The ore zinc blende is an important source of the metal zinc. What is the name of the zinc compound in zinc blende?	Marks [5]
2.	What is the zinc compound obtained by roasting zinc blende?
3.	What is the type of chemical reaction carried out after roasting in order to obtain zinc?
3.	Are liquid zinc and liquid lead miscible or immiscible?
5.	What is the name of the alloy formed between zinc and copper?
	Choice in 2000

Write the balanced equations for the preparation of the following compounds (as the major product) starting from iron and using only one other substance:		Marks [4]
1.	iron (II) chloride
2.	iron (III) chloride
3.	iron (II) sulphate
4.	iron (II) sulphide
	Compulsory in 2002

Topics Covered
1.	The Periodic Table - Periodic Properties
2.	Chemical Bonding
3.	Acids, Bases And Salts
4.	Practical Chemistry
5.	Gases, Gas Laws and Mole concept
6.	Empirical and Molecular Formula
7.	Percentage Composition
8.	Electrolysis
9.	Metallurgy
11.	Hydrogen Chloride
12.	Ammonia
13.	Nitric Acid
14.	Study of Compounds: Sulphur Dioxide, Hydrogen Sulphide, Sulphuric Acid
15.	Hydrocarbons

Advantages
1.	Topicwise presentation of all past questions allows topicwise revision. Past questions are the most important questions you must solve first.
2.	Frequency analysis shows types of past questions with marks, year reference and whether choice or compulsory, short or long.
3.	Eliminates questions on topics not part of a forthcoming Board Exam.
4.	Adds model questions for new topics in a forthcoming Board Exam.
5.	Data is presented from the most recent to earlier years, covering 10-12 years.
6.	Perfect for making strategy and for the prioritization of study objectives.

Solutions To All Past Questions

Question

Solution

Theory

Tips

a	Zinc is extracted from zinc blende. The zinc blende is roasted. The solid product is mixed with coke in a blast furnace from which zinc vapour emerges.
1.	What is the zinc compound in zinc blende?
2.	Write the equation for the roasting of zinc blende.
3.	What is the purpose of using coke?
4.	What is the reducing agent in this extraction?
5.	How is zinc vapour condensed to liquid?
b	From the metals copper, iron, magnesium, sodium and zinc select a different metal in each case which:
1.	does not react with dil. HCl
2.	can form 2+, 3+ ions
3.	has a hydroxide that reacts with both acids and alkalis.
4.	does not react with cold water but reacts with steam when heated.
c	Arrange the above metals in decreasing order of reactivity.

	[10] Choice in 2001

a
i	ZnS
ii
iii	To reduce zinc oxide to zinc.
iv	Coke
v	By a shower of molten land.
b
i	Copper
ii	Iron
iii	Zinc
iv	Magnesium
v	Sodium, Magnesium, Zinc, Iron, Copper.

Metallurgy of zinc

Step I

Concentration of the ore by froth floatation process.

Step II

Concentrated ore is converted into oxide.

Activity series :- It is a series of metals arranged according to their decreasing reactivity:
K, Na, Ca, Mg, Al, Zn, Fe, Sn, Pb, [H], Cu, Hg, Ag

1.	Read the question carefully and follow the instructions.
2.	Write correctly balanced equations.
3.	Uses to be learnt well.
4.	Copy the table according to the instructions.
5.	Learn well the reaction taking place in the blast furnace.

Advantages Solutions To All Past Questions
•	They Allow Self Check.
•	They Guide As To How And How Much To Write In The Board Exam.
•	Learn Backwards From Answers.
•	Learn How To Answer In A Board Exam.
•	Tips And Formulae To Memorize.
•	Last Minute Help: Gain Marks Even While You Sit And Read In Bed!

Revision Notes
•	Revision Notes On What Has Already Come In The Last 10-13 Years Are Helpful Throughout The Year, Just Before Examinations, Or Even The Night Before Exam. They Provide A Quick Synopsis Of Solutions And Tips On Each Topic.

Topic 5. Gases, Gas Laws and Mole Concept

Topic

No. Of Questions
(In The Last 10 Year Papers)

Guidelines

Tips

5. Gases, Gas Laws and Mole Concept

Marks for these questions range from 2 to 8. These questions have come in the compulsory and choice sections.

2004, 2003, 2002 (solved) 2001, 2000, 1999, 1998, 1997 and 1996

18 Questions
QUESTION (2002), 6 marks, compulsory
Samples of gases O2, N2, CO2 and CO under the same conditions of temperature and pressure contain the same number of molecules represented by X. The molecule of oxygen (O2) occupy v litres and have a mass of 8 g. Under the same conditions of temperature and pressure:
1.	What is the volume occupied by:
	a	X molecules of N2.
	b	3X molecules of CO?
2.	What is the mass of CO2 in grams?
3.	In answering the above questions, whose law have you used? (C=12, N=14, O=16) SOLUTION:
Solution

Gay Lussac's Law
"When gases react they do so in volumes which bears simple whole number ratio to one another and to the volumes of the products, if gaseous, provided the temperature and pressure of the reacting gases and their products remain constant."

Avogodro's Law
"Under the same conditions of temperature and pressure equal volumes of all gases contain the same number of molecules".

S.T.P. Conditions
T = 273 K or 0°C
P = 760 mm Hg
= 76 cm
= 1 Atm pressure
1 mole = 6.023 x 1023 molecules
= 22.4 lit of volume

1.	Read and understand the questions carefully.
2.	Do not get confused between Avogadro’s law and Gay Lussac’s law.
3.	Tabular form of calculations will be easy.
4.	Concepts of Mole should be given importance.
5.	Mention the units while solving numericals.
6.	Proper sequence of steps must be shown.
7.	Convert the temperature scale from Celsius to Kelvin before applying the relevant gas law in

Tick:How Do You Find This Topic?

Advantages
•	No Need To Make Separate Extensive Revision Notes.
•	Especially Excellent For Last Minute Revision.
•	Use Your Short-Term Memory To Boost Results By Reviewing These Notes The Night Before Exam, When Your Mind Is The Keenest!

Prioritize Using Smart Study Plan Interpretation
•	On Topic 5: Gases, Gas Laws and Mole Concept, there have been twenty two past questions in the last 12 years.
•	They came in the years 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997 and 1996.
•	Whether they were Compulsory or Choice questions is indicated by C or NC.
•	For example, the 2007 question was worth five marks and was Compulsory.
•	Suggested time to attempt all these 22 questions on your own is 110 minutes.

Frequency Analysis And Planning Chart

Advantages
•	Find Out Which Past Questions Were Difficult For You By Filling Out Each Circle According To How Difficult You Found A Question.
•	Study According To Your Personal Strengths.
•	Save Time By Planning Better.
•	Revise These Questions For A Second Time To Maximize Marks.
•	Have A Thorough Knowledge Of What Has Already Come In The Last 13 Years On Each Topic.

Remember

Going Over Past Questions Gives You More Confidence. Solutions To Every Past Question As Per Board Guidelines Ensure You Gain Every Possible Mark.

These Are The Most Important Hours You Will Spend Towards Preparation Of Your Board Exam.

Extras
•	How To Work Smart: 10 Keys To Success By Dr Sunita Gandhi.
•	Nutritional Guidelines By Dr Amitabh Pandit, A Well Known Naturopath.
•	Cd–Includes Ten Keys Of Dr Gandhi As Explained By The Students Of City Montessori School (Cms), Lucknow, Up And Testimonies of Students Who Have Used The Sure Success Series.

Please Note
•	Questions And Topics Not Relevant To A Future Board Exam Are Not Included.
•	New Model Questions Are Added Whenever A New Topic Has Been Included By The Council For A Forthcoming Board Exam.

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