# The number of molecules of H2SO4 present in 100 mL of 0.02 M H2SO4 solution are:  1. $12.044×{10}^{20}$ molecules 2. $6.022×{10}^{23}$ molecules 3. $1×{10}^{23}$ molecules 4. $12.044×{10}^{23}$ molecules

Subtopic:  Concentration Based Problem |
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The mass percent of carbon in carbon dioxide is:

 1 0.034% 2 27.27% 3 3.4% 4 28.7%
Subtopic:  Concentration Based Problem |
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The empirical formula and molecular mass of a compound are ${\mathrm{CH}}_{2}\mathrm{O}$ and 180 g, respectively. The molecular formula of the compound is:
1. C9H18O9
2. CH2O
3. C6H12O6
4. C2H4O2

Subtopic:  Empirical & Molecular Formula |
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If the density of the solution is 3.12 g ml-1, then what will be the mass of the 1.5 ml solution in two significant figures?

 1 $$4.4~\mathrm{g}$$ 2 $$4680 \times 10^{3} ~\mathrm{g}$$ 3 $$4.7~\mathrm{g}$$ 4 $$46.80~\mathrm{g}$$
Subtopic:  Introduction |
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The incorrect statement among the following is:

 1 A molecule of a compound has atoms of different elements. 2 A compound cannot be separated into its constituent elements by the physical method of separation. 3 A compound retains the physical properties of its constituent elements. 4 The ratio of atoms of different elements in a compound is fixed.
Subtopic:  Introduction |
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Which of the following statements is correct about the reaction is given below?

$4\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to 2{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}\left(\mathrm{g}\right)$

 1 Total mass of iron and oxygen in reactants = total mass of iron and oxygen in product therefore it follows law of conservation of mass 2 Total mass of reactants = total mass of product, therefore, law of multiple proportions is followed 3 Amount of Fe2O3 can be increased by taking any one of the reactants (iron or oxygen) in excess. 4 Amount of Fe2O3 produced will decrease if the amount of any one of the reactants (iron or oxygen) is taken in excess.

Subtopic:  Limiting Reagent |
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Identify the reaction that does not obey the law of conservation of mass from the provided options:

1. $2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right)$

2. ${\mathrm{C}}_{3}{\mathrm{H}}_{8}\left(\mathrm{g}\right)+{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to {\mathrm{CO}}_{2}\left(\mathrm{g}\right)+{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{g}\right)$

3. ${\mathrm{P}}_{4}\left(\mathrm{s}\right)+5{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to {\mathrm{P}}_{4}{\mathrm{O}}_{10}\left(\mathrm{s}\right)$

4. ${\mathrm{CH}}_{4}\left(\mathrm{g}\right)+2{\mathrm{O}}_{2}\left(\mathrm{g}\right)\to {\mathrm{CO}}_{2}\left(\mathrm{g}\right)+2{\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{g}\right)$

Subtopic:  Introduction |
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Which of the following statement indicates that the law of multiple proportions is being followed?

 1 A sample of carbon dioxide taken from any source will always have carbon and oxygen in the ratio of 1:2. 2 Carbon forms two oxides namely, CO2 and CO, where masses of oxygen that combine with a fixed mass of carbon are in the simple ratio of 2:1. 3 When magnesium burns in oxygen, the amount of magnesium used for the reaction is equal to the amount of magnesium  formed in magnesium oxide. 4 At constant temperature and pressure, 200 mL of hydrogen will combine with 100 mL of oxygen to produce 200 mL of water vapour.

Subtopic:  Introduction |
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Match the following:

 COLUMN I COLUMN II A. 88 g of CO2 1. 0.25 mol B. 6.022×1023 molecules of H2O 2. 2 mol C. 5.6 L of O2 at STP 3. 3 mol D. 96 g of O2 4. 1 mol
Codes:
 A B C D 1. 2 4 1 3 2. 1 2 3 4 3. 1 4 3 2 4. 4 1 3 2
Subtopic:  Moles, Atoms & Electrons |
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Match the following physical quantities with units.

 Physical quantity Unit A. Molarity 1. mol kg–1 B. Molality 2. mol L–1 C. Pressure 3. Candela D. Luminous intensity 4. Pascal

Codes:

 A B C D 1. 1 4 2 3 2. 2 1 4 3 3. 1 4 3 2 4. 4 1 3 2
Subtopic:  Introduction |
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