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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.
 Covering Chapters
1.
The Periodic Table - Periodic Properties
8.
Electrolysis
2.
Chemical Bonding
9.
Metallurgy
3.
Acids, Bases And Salts
10.
Hydrogen Chloride
4.
Practical Chemistry
11.
Ammonia
5.
Gases, Gas Laws and Mole concept
12.
Nitric Acid
6.
Empirical and Molecular Formula
13.
Study of Compounds: Sulphur Dioxide,Hydrogen Sulphide, Sulphuric Acid
7.
Percentage Composition
14.
Hydrocarbons
 Questions
Questions 1 (g) (i) [2]
  Find the weight of ammonia required for the preparation of 66 g of ammonium sulphate, according to the following equation:
 
  [Atomic weights: N = 14, H = 1, S = 32, O = 16]
Questions 1 (g) (ii) [2]
  4g of a metallic chloride contains 1.89 g of the metal 'X'. Calculate the empirical formula of the metallic chloride.
  [Atomic weights: X = 64, Cl=35.5]4 g of a metallic chlo
Questions 1 (g) (iii) [1]
  How many moles of nitrogen dioxide are present in
Questions 1 (b) (ii) [3]
  From the equation:
 
Calculate :
(i)
the mass of copper needed to react with 63 g of nitric acid.
(ii)
the volume of nitric oxide collected at the same time.
  [Cu = 64, H = 1, O = 16, N = 14]
 Solutions Tips and Guidelines
Solution (c)  
132 g of ammonium sulphate requires ammonia = 34 g
66 g of ammonium sulphate requires ammonia   = (34x6/132)g = 17g
Tips
(i)
First calculate the molecular weight of ammonia and ammonium sulphate  
(ii)
From the equation, 1 mole of ammonium sulphate is produced by 2 moles of ammonia.  
(iii)
Now place the values and calculate how much ammonia is required for producing 66 g of ammonium sulphate.  
Solution 1 (g) (ii)
Element

% Composition

Atomic Weight
Atomic Weight
Simplest Ratio
x
1.89
64
1.89/64=0.029
0.029/0.029=1
cl
2.11
35.5
2.11/35.5=0.059
0.059/0.029=2
The MAXIM Classbook
GEMS Dynamic Assessments
PerBooks Personalised TopicBooks
Sure Success Series
TargetPLUS On-Line Mocks
UK GCSE Mock Papers for Mathematics
GEMS “Dynamic” at a Glance
Philosophy Behind GEMS “Dynamic”
GEMS “Dynamic” Surveys and Perbooks
GEMS “Dynamic” Reports
GEMS “Dynamic” Training
GEMS “Dynamic” Lab School?
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