CBSE Board Chemistry Sample Papers for Class 11

Sample Paper 
chemistry 
Class 11

1. 1.7 g of  AgNO3
is dissolved in 100 g of water. 0.585g of NaCl dissolved in 100g
of water is added to it and chemical reaction occurs. 1.435g of AgCl and 0.85 g of
NaNO3
are formed. Justify that the data obey the law of conservation of mass
2. (a) When 4.2g of sodium bicarbonate is added to a solution of acetic acid
weighing 10g, it is observed that 2.2g of  CO2
is released into atmosphere.
The residue is found to weigh 12g. Show that these  observations are in
agreement with the law of conservation of mass.
(b) If 6.3 g of sodium bicarbonates is added to 15g of acetic acid solution, the
residue is found to weigh 18g, what is the mass of  CO2
released in the
reaction? 
3. In an experiment, 1.375g of CuO was reduced by heating in a current of hydrogen
and the weight of copper that remained was 1.098g.  In another experiment,
1.179g of  CuO  was dissolved in nitric acid and the resulting Copper(I) nitrate
converted into CuO by ignition. The weight of CuO that was formed was 1.476g.
Show that these results illustrate the law of constant proportions.
4. Carbon and oxygen are known to form two compounds.  The carbon content in
one of these is 42.9% while in the other is 27.3%.  Show that this data is in
agreement with the law of multiple proportions.
5. On analysis, it was found that black oxide of copper and red oxide of copper
contained 79.9% and 88.8% of copper respectively. Show that this data is in
accordance with the law of multiple proportions.
6. Calculate the mass of 1 molecule of nitrogen
7. Calculate the mass of 1 molecule of water and 100 molecules of C12H 22O11
8. Calculate the mass of an atom of silver (Ag = 108 amu)
9. Calculate the number of atoms in (a) 52 moles of He (b) 52 a.m.u of He (c) 52 g
of He
10. Calculate the volume occupied by the following at STP
a. 14 g of nitrogen gas
b. 1.5 gram mole of CO2Che/XI  Chapter 1


11. Calculate the number of moles in each of the following:
a. 392 g of sulphuric acid
b. 44.8 l of sulphur dioxide at STP
c.
22
.6 022 ×10 molecules of oxygen
d. 8g of Calcium
12. Calculate the number of atoms in
a. 0.5 moles of nitrogen atom
b. 0.2 moles of nitrogen molecule
c. 3.2 g of sulphur
13. Calculate the mass of an atom of  C
12
?
14. Calculate the number of atoms in 52 moles of Argon?
15. Calculate the volume at STP occupied by
21
10 molecules of oxygen?
16. Chlorophyll, the green coloring matter of plants contains 2.68% of magnesium by
weight. Calculate the number of magnesium atoms in 2g of chlorophyll.
17. Calculate the number of atoms of oxygen present in 8g of  CO2
? What would be
the weight of CO having the same number of oxygen atoms?
18. Potassium bromide (KBr) contains 32.9% by mass potassium. If 6.40g of bromine
reacts with 3.6g of potassium, calculate the number of moles of potassium which
combines with bromine to form KBr.
19. What mass of calcium oxide will be obtained by heating 3 moles of calcium
carbonate?
20. Calculate the percentage composition of the following:
a. Urea    NH 2CONH 2
b. Glucose C6 H12O6
21. The molecular mass of an organic compound is 78 g and its percentage
composition is Carbon: 92.4% and hydrogen: 7.6%. Determine the molecular
formula of the compound
22. A compound has the following composition:
Mg – 9.76%, S – 13.01%, O – 26.01%,  H 2O − 51 22. % . Find its empirical
formula.
23. An organic compound has the following percentage composition: Che/XI  Chapter 1
Some basic concepts of Chemistry

3
Carbon: 57.8%, Hydrogen: 3.6% and oxygen: 39.6%. Vapour density of the
compound was found to be 83. Find the molecular formula.
 
24. A compound has the composition Na-14.31%, S-9.97%, H-6.22% and O-69.5%.
Calculate the molecular formula assuming that all the hydrogen in the compound
is present in combination with oxygen as water of crystallization. The molecular
mass is 322
  
25. Butyric acid contains carbon, hydrogen and oxygen.  4.2 mg sample of butyric
acid is completely burnt to give 8.45 mg of  CO2
and 3.46 mg of water. What is
the mass percent of each element in the acid?