Problem 36
A mixture of \(\mathrm{O}_{2}\) and gas " \(Y\) " (mol. wt. 80) in the mole ratio \(a: b\) has a mean molecular weight 40\. What would be mean molecular weight, if the gases are mixed in the ratio \(b: a\) under identical conditions ? (gases are non-reacting): (a) 40 (b) 48 (c) 62 (d) 72
Problem 37
If water sample are taken from sea, rivers or lake, they will be found to contain hydrogen and oxygen in the approximate ratio of \(1: 8\). This indicates the law of: (a) Multiple proportion (b) Definite proportion (c) Reciprocal proportions (d) None of these
Problem 40
Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively \(12: 16\) and \(12: 32\). These figures illustrate the : (a) Law of multiple proportions (b) Law of reciprocal proportions (c) Law of conservation of mass (d) Law of constant proportions
Problem 41
A sample of calcium carbonate \(\left(\mathrm{CaCO}_{3}\right)\) has the following percentage composition : \(\mathrm{Ca}=40 \%\), \(\mathrm{C}=12 \%, \mathrm{O}=48 \%\). If the law of constant proportions is true, then the weight of calcium in \(4 \mathrm{~g}\) of a sample of calcium carbonate obtained from another source will be : (a) \(0.016 \mathrm{~g}\) (b) \(0.16 \mathrm{~g}\) (c) \(1.6 \mathrm{~g}\) (d) \(16 \mathrm{~g}\)
Problem 42
The law of multiple proportion is illustrated by the two compounds: (a) Sodium chloride and sodium bromide (b) Ordinary water and heavy water (c) Caustic soda and caustic potash (d) Sulphur dioxide and sulphur trioxide
Problem 44
One mole of element \(X\) has \(0.444\) times the mass of one mole of element \(Y .\) One atom of element \(X\) has \(2.96\) times the mass of one atom of \({ }^{12} \mathrm{C}\). What is the atomic weight of \(Y ?\) (a) 80 (b) \(15.77\) (c) \(46.67\) (d) \(40.0\)
Problem 45
A given sample of pure compound contains \(9.81 \mathrm{gm}\) of \(\mathrm{Zn}, 1.8 \times 10^{23}\) atoms of chromium and \(0.60\) mole of oxygen atoms. What is the simplest formula ? (a) \(\mathrm{ZnCr}_{2} \mathrm{O}_{7}\) (b) \(\mathrm{ZnCr}_{2} \mathrm{O}_{4}\) (c) \(\mathrm{ZnCrO}_{4}\) (d) \(\mathrm{ZnCrO}_{6}\)
Problem 46
The formula of an acid is \(\mathrm{H} X \mathrm{O}_{2}\). The mass of \(0.0242\) moles of the acid is \(1.657 \mathrm{~g}\). What is the atomic weight of \(X ?\) (a) \(35.5\) (b) \(28.1\) (c) 128 (d) \(19.0\)
Problem 47
What is the empirical formula of vanadium oxide, if \(2.74 \mathrm{~g}\) of the metal oxide contains \(1.53 \mathrm{~g}\) of metal ? (a) \(\mathrm{V}_{2} \mathrm{O}_{3}\) (b) VO (c) \(\mathrm{V}_{2} \mathrm{O}_{5}\) (d) \(\mathrm{V}_{2} \mathrm{O}_{7}\)
Problem 48
Determine the empirical formula of Kelvar, used in making bullet proof vests, is \(70.6 \% \mathrm{C}, 4.2 \%\) \(\mathrm{H}, 11.8 \% \mathrm{~N}\) and \(13.4 \% \mathrm{O}\) : (a) \(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{NO}_{2}\) (b) \(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{~N}_{2} \mathrm{O}\) (c) \(\mathrm{C}_{7} \mathrm{H}_{9} \mathrm{NO}\) (d) \(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{NO}\)
