(i) 28.7 pm $1 pm = 10^{ -12 } \; m$ $28.7 pm = 28.7 \times 10^{ -12 } \; m$ $= 2.87 \times 10^{ -11 } \; m$ (ii) 15.15 pm $1 pm = 10^{ -12 } \; m$ $15.15 pm = 15.15 \times 10^{ -12 } \; m$...
(i) Empirical formula 1 mole of $CO_{ 2 }$ contains 12 g of carbon Therefore, 3.38 g of $CO_{ 2 }$ will contain carbon = $\frac{ 12 \; g }{ 44 \; g } \; \times 3.38 \; g$ = 0.9217 g 18 g of...
Mass percent of HNO3 in sample is 69 % Thus, 100 g of HNO3 contains 69 g of HNO3 by mass. Molar mass of HNO3 = { 1 + 14 + 3(16)} g.mol^{-1}g.mol−1 = 1 + 14 + 48 = 63g mol^{-1}=63gmol−1 Now,...
When two elements combine to form two or more chemical compounds, then the mass of one of the compounds in a fixed mass of the other holds a simple measure of each other is the law of equality....
CaCO3 (s) + 2HCl (aq) → CaCl2(aq) + CO2(g) + H2O(l) What mass of CaCl2 will be formed when 250 mL of 0.76 M HCl reacts with 1000 g of CaCO3? Name the limiting reagent. Calculate the number of moles...
(i) Calculation: Moles of oxygen = 1.6/32 Moles of oxygen = 0.05mol 1 mol of oxygen= 22.4L (at STP) Volume of Oxygen (V1) = 22.4 × 0.05 Volume of Oxygen (V1) = 1.12L V2 =? P1 = 1atm P2 = ½ P2 =...
Correct Answer: (ii) Both A and R are true but R is not the correct explanation of A Explanation: The carbon 12 isotope defines the mass of atoms and molecules.
Correct Answer: (i) Both A and R are true and R is the correct explanation of A Explanation: The empirical formula represents the simplest whole-number the ratio of various atoms present in a...
Physical quantity Unit (i) Molarity (a) g mL–1 (ii) Mole fraction (b) mol (iii) Mole (c) Pascal (iv) Molality (d) Unitless (v) Pressure (e) mol L–1 (vi) Luminous intensity (e) mol L–1 (vii) Density...
(i) 88 g of CO2 (a) 0.25 mol (ii) 6.022 ×1023 molecules of H2O (b) 2 mol (iii) 5.6 litres of O2 at STP (c) 1 mol (iv) 96 g of O2 (d) 6.022 × 1023 molecules (v) 1 mol of any gas (e) 3 mol ...
Calculation: Mole fraction of H2O = Number of moles of H2O / Total number of moles (H2O +NaOH) Number of moles of H2O = 36/18 Number of moles of H2O =2 moles Number of moles of NaOH = 4/40 Number of...
The Mass do not change when the temperature changes and so the molality of a solution do not change as well. Molality of a substance is defined as the number of mass of solute per mass of the...
Zn + 2HCl → ZnCl2 + H2 Calculate the volume of hydrogen gas liberated at STP when 32.65 g of zinc reacts with HCl. 1 mol of a gas occupies 22.7 L volume at STP; atomic mass of Zn = 65.3 u. ...
(a) If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in whole-number ratio and this statement is true....
Calculation: Molecular mass of Ca3(PO4) = (3 X 40) + (2 X 31) + (8 X 16) Molecular mass of Ca3(PO4) = 310 Mass percentage of Ca = \[\frac{3\times 40}{310\times 100}\] Mass percentage of Ca = 38.71%...
Molarity Molality Number of moles per volume of the solution in litres Number of mass of solute per mass of the solvent in liters Unit - M Unit - m
Mole is the amount of substance containing more entities because there are atoms in 12 g of carbon. SI unit symbol – mol
Number Significant figures 2.5 2 1.25 3 3.5 2 2.01 3 In the given calculation, involving both the multiplication and division, the significant figures present is 2. Hence, the result cannot have...
1 mole of carbon atom = 12g Therefore, Mass of one atom of C-12 in grams= 1.99 × 1023 grams.
Correct Answers: (i) Law of conservation of mass; (iv) Avogadro's law Explanation: According to the Dalton's atomic theory, The Chemical compounds are formed when atoms of various elements join in a...
(i) 20 g of NaOH in 200 mL of solution (ii) 0.5 mol of KCl in 200 mL of solution (iii) 40 g of NaOH in 100 mL of solution (iv) 20 g of KOH in 200 mL of solution Answer: Correct Answers: (i)...
(i) 16 g of O2(g) and 4 g of H2(g) (ii) 16 g of O2 and 44 g of CO2 (iii) 28 g of N2 and 32 g of O2 (iv) 12 g of C(s) and 23 g of Na(s) Answer: Correct Answers: (iii) 28 g of N2 and 32 g of...
H2SO4 + 2NaOH → Na2SO4+ 2H2O When 1L of 0.1M sulphuric acid solution is allowed to react with 1L of 0.1M sodium hydroxide solution, the amount of sodium sulphate formed and its molarity in the...
(i) 6.022 × 1023 molecules of oxygen (ii) 6.022 × 1023 atoms of oxygen (iii) 16 g of oxygen (iv) 32 g of oxygen Answer: Correct Answers: (i) 6.022 × 1023 molecules of oxygen; (iv) 32 g of...
(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 a...
(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) Answer: Correct Answer: (ii) C3H8(g) + O2(g) →...
Correct Answer: (i) The total mass of iron and oxygen in reactants = total mass of iron and oxygen in product therefore it follows the law of conservation of mass. Explanation: From the reaction,...
Correct Answer: (iii) A compound retains the physical properties of its constituent elements Explanation: Molecule of a compound is made up of atoms of various elements which cannot be separated...
Correct Answer: (i) 4.7g Explanation: Given, Density of solution = 3.12 g mL-1 Volume of solution = 1.5 mL Formula for Mass = Volume × Density Hence, Mass = 4.7 g
Correct Answer: (iii) C6H12O6 Explanation: Given, Molar mass of Carbon=12 Molar mass of Hydrogen=1 Molar mass of Oxygen=16 So, The molecular weight of compound is 6 and so the molecular formula of...
Correct Answer: (ii) 27.27% Explanation: Carbon dioxide is a gas with a density of about 53% higher than that of dry air. Carbon dioxide molecules consist of a double carbon atom combined with two...
Correct Answer: (i) 12.044 × 1020 molecules Explanation: Moles of H2SO4= Molarity of H2SO4×Volume of solution (L) Hence, the number of molecules of H2SO4 present in 100 mL of 0.02M H2SO4 solution...