Free NEET Chemistry multiple-choice questions on Atomic & Molecular Masses. Attempt each question and reveal the answer with a full explanation.
How many significant figures are there in 500.0 ? 4 1 3 2 The vapor density of a gas is 22 . Its molecular mass will be: 44 11 22 88 Relative atomic mass is calculated with respect to: 1/12 th mass of one C-12 atom Mass of one H atom 1/16 th mass of one O-16 atom Mass of one C-12 atom The number of significant figures in the speed of light ( 299,792,458 m/s ) is: 9 Infinite 8 1 Copper has face centered cubic (fcc) lattice with interatomic spacing equal to 2.54 . The value of lattice constant for this lattice is- 3.59 2.54 1.27 5.08 An element, X has the following isotopic composition: 200 X : 90% 199 X : 8.0 % 202 X : 2.0 % The weighted average atomic mass of the naturally occuring element X is closest to 201 amu 202 amu 199 amu 200 amu Boron has two stable isotopes, 10 B ( 19.9 % ) and 11 B ( 80.1 % ). Calculate the average atomic mass of Boron. 10.81 u 10.20 u 11.00 u 10.50 u An element X has the following isotopic composition: 200 X: 90 % , 199 X: 8 % , 202 X: 2 % . The weighted average atomic mass of the naturally occurring element X is closest to: 200 u 201 u 202 u 199 u Given that the abundance of isotopes 54 Fe , 56 Fe and 57 Fe are 5 %, 90 % and 5 % respectively, the atomic mass of Fe is: 55.95 56.05 55.85 56.00 The specific heat of a metal is 0.11 cal/g C . Its approximate atomic mass is: 58.18 28.5 11.0 110.0 An element X has three isotopes with masses 24 , 25 , and 26 . Their relative abundances are 78.99 % , 10.00 % , and 11.01 % respectively. The average atomic mass of the element X is: 24.31 u 24.99 u 25.00 u 23.99 u The number of significant figures in 6.022 10 23 is: 4 23 2 Infinite The average atomic mass of an element X is 16.2 u . There are two isotopes 16 X and 18 X . The percentage abundance of 16 X is: 90% 10% 80% 20% The maximum number of atoms are present in 1 g of which of the following? Li (s) C (s) Fe (s) Pb (s) If the abundance of 10 B and 11 B isotopes are x and (100-x) and the average atomic mass is 10.8 , then x is: 20 80 19 25 Sodium has body centred packing. Distance between two nearest atoms is 3.7 . The lattice parameter is : 8.6 6.8 4.3 3.0 Copper crystallizes in a face-centred cubic lattice with a unit cell length of 361 pm. What is the radius of copper atom in pm ? 108 128 157 181 Which of the following statements about hydrogen is incorrect ? hydrogen has three isotopes of which tritium is the most common. Hydrogen never acts as cation in ionic salts Hydronium ion, H3O+ exists freely in solution Dihydrogen does not act as a reducing agent Identify the incorrect match. array ll Name & IUPAC Official Name (a) Unnilunium & (i) Mendelevium (b) Unniltrium & (ii) Lawrencium (c) Unnilhexium & (iii) Seaborgium (d) Unununnium & (iv) Darmstadtium array (b), (ii) (c), (iii) (d), (iv) (a), (i) The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are 17.014 and 21.023 17.015 and 21.023 17.014 and 21.024 17.015 and 21.024 The number of significant figures in 100.0 is: 4 3 1 2 One unified atomic mass unit ( 1 u ) is equal to: 1.66 10 -27 kg 1.66 10 -24 kg 9.1 10 -31 kg 6.022 10 -23 kg Express 0.00000000000456 in scientific notation. 4.56 10 -12 4.56 10 -11 45.6 10 -13 4.56 10 -10 The average atomic mass of Chlorine is 35.5 u . The ratio of 35 Cl to 37 Cl isotopes in naturally occurring chlorine is: 3:1 1:1 2:1 4:1 Which of the following units represents the smallest length? 1 picometer 1 Angstrom 1 nanometer 1 micrometer Which of the following is the standard for defining atomic mass unit? C-12 H-1 O-16 N-14 Calculate the average molar mass of a mixture of 80 % Nitrogen (N 2) and 20 % Oxygen (O 2) by moles. 28.8 g/mol 30.0 g/mol 29.4 g/mol 31.2 g/mol