CHEMISTRY set-b
Class XI
TEST-1
max marks :30
SOME BASIC CONCEPTS OF CHEMISTRY
Choose the best answer
1) Which has maximum number of molecules?
a)
7g of N2
b)2 g of H2
c) 16g of NO2
d)16g of O2
2) The mass of 1 mol of a substance in gram is called its
a) Atomic mass b) molecular weight c) molecular mass d)molar mass
3) 20Kg of N2 (g) and 3.0 kg of H2 (g ) are mixed to produce NH3(g).The amount of NH3 formed
a) 17Kg
b)34 Kg
C)20kg
d)3 kg
4) What is the mass percent of carbon in carbon dioxide?
a) 0.034%
b) 27.27%
c) 3.4%
d) 28.7%
5) With increase of temperature, which of these changes
a) Molality
b) weight fraction of solute
c) Molarity
d) mole fraction
6) What will be the molality of the solution containing 18.25g of HCl gas in 500g of water?
a)0.1m
b)1M
c)0.5m
d)1m
7) Which one of the following will have largest number of atoms?
a)
1g of Au
b)1g of Na c)1g of Li
d)1g of Cl2
8.. Calculate the molar mass of
i) CuSO4.5H2O (Cu=63.5, S=32
9. How many significant figures are present in the following
i) 0.0025
ii) C12 H22 O11 (2)
ii) 12000 (2)
10. i) How much copper can be obtained from 100g of copper sulphate (Cu=63.5) (2)
ii) State law of multiple proportions.
11. Dinitrogen and dihydrogen react with each other to produce ammonia according to the chemical
equation.N2 (g) + 3 H2 (g)
2NH3 (g)
(i) Calculate the mass of ammonia produced if 2 x 10 3 g of dinitogen react with
1 x 10 3 g of dihydrogen Will any of the two reacts remain unreacted? If yes, which one and what
would be its mass .(2)
12.
Calculate the number of atoms in each of the following (3)
(i) 52 moles of He
(ii) 52 u of He
(iii) 52 g of He
13. welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives
3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L (measured at S.T.P.)
of this welding gas is found to weigh 11.6 g. Calculate (i) empirical formula, (ii) molar mass of the gas,
and (iii) molecular formula.(3)
14 .Calculate the concentration of nitric acid in moles per litre in a sample which has a density 1.41
g mL-1 and the mass percent of nitric acid in it is being 69%. (2)
15. A compound contains 4.07% hydrogen, 24.27% carbon and 71.65% chlorine. Its molecular mass is
98.96. What are its empirical and molecular formulae? (2)
16. The density of 3M solution of NaCl is 1.25g mL-1. Calculate the molality of the solution (2)
17. Calculate mass percentage of benzene and carbon tetrachloride if 22g of benzene is dissolved in 122g
of carbon tetrachloride to get a solution. (2)
18. How are 0.50mol NaOH and 0.50M NaOH different? (1)
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