Plzzz provide imp.ques of CBSE 11 Chemistry Ch 2,3
On Monday I have S.A.I (Half yearly )exam of Chemistry
Answers
Multiple Choice Questions (Type-I)
Two students performed the same experiment separately and each one of them recorded two readings of mass which are given below. Correct reading of mass is 3.0 g. On the basis of given data, mark the correct option out of the following statements.
(i) Results of both the students are neither accurate nor precise.
(ii) Results of student A are both precise and accurate.
(iii) Results of student B are neither precise nor accurate.
(iv) Results of student B are both precise and accurate.
A measured temperature on Fahrenheit scale is 200 °F. What will this reading be on Celsius scale?
(i) 40 °C
(ii) 94 °C
(iii) 93.3 °C
(iv) 30 °C
What will be the molarity of a solution, which contains 5.85 g of NaCl(s) per 500 mL?
(i) 4 mol L–1
(ii) 20 mol L–1
(iii) 0.2 mol L–1
(iv) 2 mol L–1
If 500 mL of a 5M solution is diluted to 1500 mL, what will be the molarity of the solution obtained?
(i) 1.5 M
(ii) 1.66 M
(iii) 0.017 M
(iv) 1.59 M
The number of atoms present in one mole of an element is equal to Avogadro number. Which of the following element contains the greatest number of atoms?
(i) 4g He
(ii) 46g Na
(iii) 0.40g Ca
(iv) 12g He
If the concentration of glucose (C6H12O6) in blood is 0.9 g L–1 , what will be the molarity of glucose in blood?
(i) 5 M
(ii) 50 M
(iii) 0.005 M
(iv) 0.5 M
What will be the molality of the solution containing 18.25 g of HCl gas in 500 g of water?
(i) 0.1 m
(ii) 1 M
(iii) 0.5 m
(iv) 1 m
One mole of any substance contains 6.022 × 1023 atoms/molecules. Number of molecules of H2SO4 present in 100 mL of 0.02M H2SO4 solution is ______
(i) 12.044 × 1020 molecules
(ii) 6.022 × 1023 molecules
(iii) 1 × 1023 molecules
(iv) 12.044 × 1020 molecules
What is the mass percent of carbon in carbon dioxide?
(i) 0.034%
(ii) 27.27%
(iii) 3.4%
(iv) 28.7%
The empirical formula and molecular mass of a compound are CH2O and 180 g respectively. What will be the molecular formula of the compound?
(i) C9H18O9
(ii) CH2O
(iii) C6H12O6
(iv) C2H4O2
If the density of a solution is 3.12 g mL-1, the mass of 1.5 mL solution in significant figures is _______.
(i) 4.7g
(ii) 4680 × 10-3 g
(iii) 4.680g
(iv) 46.80g
Which of the following statements about a compound is incorrect?
(i) A molecule of a compound has atoms of different elements.
(ii) A compound cannot be separated into its constituent elements by physical methods of separation.
(iii) A compound retains the physical properties of its constituent elements.
(iv) The ratio of atoms of different elements in a compound is fixed.
Which of the following statements is correct about the reaction given below:
4Fe(s) + 3O2 (g) → 2Fe2O3(g)
(i) Total mass of iron and oxygen in reactants = total mass of iron and oxygen in product therefore it follows law of conservation of mass.
(ii) Total mass of reactants = total mass of product; therefore, law of multiple proportions is followed.
(iii) Amount of Fe 2 O 3 can be increased by taking any one of the reactants (iron or oxygen) in excess.
(iv) Amount of Fe 2 O 3 produced will decrease if the amount of any one of the reactants (iron or oxygen) is taken in excess.
Which of the following reactions is not correct according to the law of conservation of mass.
(i) 2Mg(s) + O2(g) → 2MgO(s)
(ii) C3H8(g) + O2(g) → CO2(g) + H2O(g)
(iii) P4(s) + 5O2(g) → P4O10(s)
(iv) CH4(g) + 2O2(g) → CO2(g) + 2H2O (g)
Which of the following statements indicates that law of multiple proportion is being followed.
(i) Sample of carbon dioxide taken from any source will always have carbon and oxygen in the ratio 1:2.
(ii) Carbon forms two oxides namely CO2 and CO, where masses of oxygen which combine with fixed mass of carbon are in the simple ratio 2:1.
(iii) When magnesium burns in oxygen, the amount of magnesium taken for the reaction is equal to the amount of magnesium in magnesium oxide formed.
(iv) At constant temperature and pressure 200 mL of hydrogen will combine with 100 mL oxygen to produce 200 mL of water vapour.