Mole, molar mass, Avogadro number and molar volume

37 questions on Mole, molar mass, Avogadro number and molar volume from the Mole Concept chapter: 8 NEET level, 14 JEE Main, 15 JEE Advanced. Each one opens with its answer and solution.

• The number of molecules present in 3.6 g of water (H2O, M = 18 g mol^-1) is (use N_A = 6.02x10^23 mol^-1): NEET level
• What is the mass of 0.25 mol of calcium carbonate, CaCO3? (Ca = 40, C = 12, O = 16) NEET level
• The volume occupied at STP by 8.8 g of carbon dioxide is (C = 12, O = 16; molar volume at STP = 22.4 L mol^-1): NEET level
• The total number of atoms in 0.5 mol of ammonia, NH3, is (use N_A = 6.02x10^23 mol^-1): NEET level
• Which of the following samples contains the largest number of atoms? (H = 1, C = 12, O = 16) JEE Main level
• A gas has a density of 2.857 g L^-1 at STP (molar volume 22.4 L mol^-1). Which gas is it? (C = 12, N = 14, O = 16, S = 32, Cl = 35.5) JEE Main level
• The mass of a single copper atom (Cu = 63.5) in grams is (use N_A = 6.02x10^23 mol^-1): JEE Main level
• The total number of electrons in 1.8 g of water (H = 1, O = 16; use N_A = 6.02x10^23 mol^-1) is: JEE Main level
• How many grams of sodium contain the same number of atoms as 4.8 g of magnesium? (Na = 23, Mg = 24). Give the answer to one decimal place. JEE Main level
• A gas mixture contains 1.204x10^23 molecules of H2 and 7.1 g of Cl2 (Cl = 35.5). Using N_A = 6.02x10^23 mol^-1 and 22.4 L mol^-1 at STP, find the volume of the ... JEE Main level
• Consider 16 g of O2 and 16 g of O3 (O = 16). Which of the following statements is/are correct? JEE Main level
• A gold foil has area 2.0 cm^2 and thickness 1.0x10^-4 cm. The density of gold is 19.7 g cm^-3 (Au = 197, N_A = 6.02x10^23 mol^-1). The number of gold atoms in t... JEE Advanced level
• A mixture of methane (CH4) and ethane (C2H6) occupies 5.6 L at STP and has a mass of 5.4 g (C = 12, H = 1; molar volume 22.4 L mol^-1). The number of hydrogen a... JEE Advanced level
• Rock salt has density 2.16 g cm^-3 (Na = 23, Cl = 35.5, N_A = 6.02x10^23 mol^-1). Treat the crystal as built of independent NaCl formula units. The average volu... JEE Advanced level
• Element X has two isotopes, of atomic masses 69 and 71, and its average atomic mass is 69.8. What mass (in g) of the heavier isotope is present in a 34.9 g samp... JEE Advanced level
• A gas mixture of total mass 24 g contains equal masses of CH4 and SO2 (C = 12, H = 1, S = 32, O = 16). Using 22.4 L mol^-1 at STP, find the volume of the mixtur... JEE Advanced level
• Sample P is 4.4 g of CO2 and sample Q is 2.24 L of N2O at STP (C = 12, N = 14, O = 16; 22.4 L mol^-1 at STP). Which of the following statements is/are correct? JEE Advanced level
• Consider 0.5 mol of aluminium sulfate, Al2(SO4)3 (Al = 27, S = 32, O = 16). Which of the following statements is/are correct? JEE Advanced level
• The number of water molecules in 3.6 g of water (H2O = 18 g mol^-1) is (take N_A = 6.02x10^23 mol^-1) NEET level
• What is the mass of 6.72 L of methane (CH4, M = 16 g mol^-1) measured at STP? Use 22.4 L/mol at STP. NEET level
• The total number of atoms in 0.5 mol of ammonia, NH3, is (take N_A = 6.02x10^23 mol^-1) NEET level
• The molar mass of CuSO4.5H2O is (Cu = 63.5, S = 32, O = 16, H = 1; in g mol^-1) NEET level
• The mass of a single glucose molecule (C6H12O6, M = 180 g mol^-1) in grams is (take N_A = 6.02x10^23 mol^-1) JEE Main level
• A gas mixture contains 4.4 g of CO2 and 2.8 g of N2 (C=12, N=14, O=16). Its volume at STP is JEE Main level
• An iron ore sample of mass 50 g contains 80% by mass Fe2O3 (rest has no iron). The mass of iron in the sample is (Fe=56, O=16) JEE Main level
• A hydrocarbon contains 85.7% carbon and 14.3% hydrogen by mass and has a molar mass of 56 g mol^-1. Its molecular formula is (C=12, H=1) JEE Main level
• How many electrons are present in 3.6 g of water (H2O, M = 18)? Take N_A = 6.02x10^23 mol^-1. Give the answer in units of 10^23, to two decimal places. JEE Main level
• The density of nitrous oxide, N2O (N=14, O=16), at STP in g L^-1 (molar volume 22.4 L/mol) is? Give the answer to two decimal places. JEE Main level
• Which of the following contain the same number of atoms as 4 g of helium (He=4, monatomic)? Use 22.4 L/mol at STP. JEE Main level
• 2.86 g of a crystalline hydrate Na2CO3.xH2O loses all its water of crystallisation on heating and leaves 1.06 g of anhydrous Na2CO3 (Na=23, C=12, O=16, H=1). Th... JEE Advanced level
• A gold leaf of area 1.0 cm^2 and thickness 1.0x10^-5 cm is made from gold of density 19.7 g cm^-3 (Au=197). The number of gold atoms in the leaf is (take N_A = ... JEE Advanced level
• A gas mixture contains methane (CH4, 16) and oxygen (O2, 32) in a mass ratio 1 : 4. The density of the mixture at STP (22.4 L/mol) is JEE Advanced level
• A compound contains 40% C, 6.67% H and 53.33% O by mass. 0.90 g of its vapour occupies 224 mL at STP (22.4 L/mol). Its molecular formula is (C=12, H=1, O=16) JEE Advanced level
• Natural copper has two isotopes, ^63Cu and ^65Cu (take their masses as 63 and 65), and an average atomic mass of 63.62. How many ^65Cu atoms are present in 12.7... JEE Advanced level
• A mixture of hydrogen (M=2) and helium (M=4) has total mass 5.0 g and occupies 33.6 L at STP (22.4 L/mol). Find the mole percent of helium, to the nearest integ... JEE Advanced level
• Consider 0.1 mol of Al2(SO4)3 (Al=27, S=32, O=16) treated as fully ionised in solution. Which statements are correct? JEE Advanced level
• In which of the following pairs do the two samples contain the same total number of atoms? (H=1, C=12, N=14, O=16; 22.4 L/mol at STP) JEE Advanced level