1.
The number of significant figures for the three numbers 161 cm, 0.161 cm, 0.0161 cm are
2.
0.24 g of a volatile gas, upon vaporisation, gives 45 mL vapour at NTP. What will be the vapour density of the substance? (Density of H₂ = 0.089)
3.
In the final answer of the expression (29.2 − 20.2) × (1.79 × 10⁵) ÷ 1.37, the number of significant figures is
4.
The molecular weight of O₂ and SO₂ are 32 and 64 respectively. At 15°C and 150 mmHg pressure, 1 L of O₂ contains ‘N’ molecules. The number of molecules in 2 L of SO₂ under the same conditions of temperature and pressure will be
5.
An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is [At. wt. of C is 12, H is 1]
6.
The number of protons, neutrons and electrons in ₇₁¹⁷⁵Lu, respectively, are
7.
Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. When 0.1 mole of XY₂ weighs 10 g and 0.05 mole of X₃Y₂ weighs 9 g, the atomic weights of X and Y are
8.
An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C: 38.71% and H: 9.67%. The empirical formula of the compound would be
9.
An element X has the following isotopic composition: ²⁰⁰X: 90%, ¹⁹⁹X: 8.0%, ²⁰²X: 2.0%. The weighted average atomic mass of the naturally occurring element X is closest to
10.
Which of the following is isoelectronic?
11.
An organic compound containing C, H, and N gave the following results on analysis: C = 40%, H = 13.33%, N = 46.67%. Its empirical formula would be
12.
An organic compound contains C = 40%, O = 53.34%, and H = 6.60%. The empirical formula of the compound is
13.
Boron has two stable isotopes, ¹⁰B (19%) and ¹¹B (81%). Calculate average atomic weight of boron in the periodic table.
14.
While extracting an element from its ore, the ore is ground and leached with dil. KCN solution to form the soluble product potassium argentocyanide. The element is
15.
A metal oxide has the formula Z₂O₃. It can be reduced by hydrogen to give free metal and water. 0.1596 g of the metal oxide requires 6 mg of hydrogen for complete reduction. The atomic weight of the metal is
16.
One mole of carbon atom weighs 12 g, the number of atoms in it is equal to (Mass of carbon-12 is 1.9926 × 10⁻²³ g)
17.
Which one of the followings has maximum number of atoms? (Atomic masses: Mg = 24, O = 16, Li = 7, Ag = 108)
18.
In which case is the number of molecules of water maximum?
19.
If Avogadro's number (Nₐ) is changed from 6.022 × 10²³ mol⁻¹ to 6.022 × 10²⁰ mol⁻¹, how would this change affect the calculations involving the number of molecules?
20.
How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO₃? The concentrated acid is 70% HNO₃.
21.
6.02 × 10²⁰ molecules of urea are present in 100 mL of its solution. The concentration of the solution is
22.
The number of atoms in 0.1 mole of a triatomic gas is (Nₐ = 6.023 × 10²³ mol⁻¹)
23.
Volume occupied by one molecule of water (density = 1 g/cm³) is
24.
The maximum number of molecules are present in
25.
Percentage of Se in peroxidase anhydrase enzyme is 0.5% by weight (atomic weight = 78.4), then minimum molecular weight of peroxidase anhydrase enzyme is
26.
The number of atoms in 4.25 g of NH₃ is approximately
27.
Haemoglobin contains 0.33% of iron by weight. The molecular weight of haemoglobin is approximately 67200 g. The number of iron atoms (atomic weight of Fe is 56) present in one molecule of haemoglobin are
28.
The number of moles of oxygen in 1 L of air containing 21% oxygen by volume, under standard conditions, is
29.
The percentage weight of Zn in white vitriol [ZnSO₄·7H₂O] is approximately equal to (atomic mass of Zn = 65, S = 32, O = 16, H = 1)
30.
The total number of valence electrons in 4.2 g of N₃⁻ ion is (Nₐ is the Avogadro’s number)
31.
The number of gram molecules of oxygen6.02 × 10²⁴ CO molecules
32.
The number of oxygen atoms in 4.4 g of CO₂ is
33.
Ratio of Cₚ and Cᵥ of a gas 'X' is 1:4. The number of atoms of the gas 'X' present in 11.2 L of it at NTP will be
34.
1 cc of N₂O₂ at NTP contains
35.
At STP, the density of CCl₄ vapour in g/L will be nearest to
36.
The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is
37.
20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (Atomic weight of Mg = 24)
38.
What is the mass of precipitate formed when 50 mL of 16.9% solution of AgNO₃ is mixed with 50 mL of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)
39.
When 22.4 L of H₂(g) is mixed with 11.2 L of Cl₂(g), each at STP, the moles of HCl(g) formed is equal to
40.
1.0 g of magnesium is burnt with 0.56 g of oxygen in a closed vessel. Which reactant is left in excess and how much?
41.
10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be
42.
How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl?
43.
What volume of oxygen gas (O₂) measured at 0°C and 1 atm, is needed to burn completely 1L of propane gas (C₃H₈) measured under the same conditions?
44.
Number of moles of MnO₄⁻ required to oxidise one mole of ferrous oxalate completely in acidic medium will be
45.
The number of moles of KMnO₄ that will be needed to react with one mole of sulphite ion in acidic solution is
