Answer:
4. False
5. False.
6. (b) One mole of a substance contains 6.022 x 10²³ particles of that substance
(c) There are 6.022 x 10²³ carbon atoms in 12.00 g of carbon-12.
7. The correct option is (A) 3H₂SO₄
8. (b) 1.71 * 10³⁷ atoms of hydrogen
Explanation:
4. 1.00 mole of Ca(NO3)2 contains the same mass of N as 1.00 mole of NaNO3 is False because 1 mole of Ca(NO3)2 contains 2 moles (28 g) of N atoms whereas 1 mole of NaNO3 contains 1 mole (14 g) of N atoms
5. The theoretical yield of a reaction is generally less than the actual yield is False because it is the actual yield of a reaction that is always less than the theoretical yield due to some incomplete reactions.
The actual yield is obtained from carrying out the actual reaction while the theoretical yield is calculated from the equation of the reaction.
6. A mole of a substance is defined as the amount of that substance which contains as many elementary particles as there are in 12 g of carbon-12.
From experiments, it was discovered that 12 g of carbon -12 contains 6.02 * 10²³ atoms, therefore, a mole of a substance can also be defined as the amount of that substance which contains 6.02 * 10²³ particles of that substance.
(a) One mole of a substance contains as many particles as exactly 12 amu of carbon-12 is false because 12 amu is the mass of 1 atom of carbon-12 and not a mole of carbon-12.
(b) One mole of a substance contains 6.022 x 1023 particles of that substance is true from the definitions above
(c) There are 6.022 x 1023 carbon atoms in 12.00 g of carbon-12 is true from the definitions above.
(d) Because it is heavier, a mole of iodine atoms contains more particles than a mole of bromine atoms is false because, irrespective of difference in their masses, a mole of all substances contain the same number of particles- 6.02 * 10²³.
7. The balanced chemical equation of the reaction of sulfuric acid with hematite (Fe2O3) to produce iron (III) sulfate and water is as follows: .
Fe₂O₃ + 3H₂SO₄ -----> Fe₂(SO₄)₃ + 3H2O
The correct option is (A) 3H₂SO₄
8. Mass of natural gas = 1.14 * 10¹¹ Kg.
Mass of natural gas in grams = 1.14 * 10¹¹ * 10³ g = 1.14 * 10¹⁴ g
Molar mass of CH₄ = 16g/mol
Number of moles of CH₄ in 1.14 * 10¹⁴ g = 1.14 * 10¹⁴ g/ 16 gmol⁻¹ = 7.125 * 10¹² moles
1 mole of CH₄ contains 4 moles of hydrogen atoms.
7.125 * 10¹² moles of CH₄ will contain 4 * 7.125 * 10¹² moles of hydrogen atoms = 2.85 * 10¹³ moles of hydrogen atoms
1 mole of hydrogen atoms contain 6.02 * 10²³ atoms of hydrogen
2.85 * 10¹³ moles of hydrogen atoms will contain 2.85 * 10¹³ * 6.02 * 10²³ atoms of hydrogen = 1.71 * 10³⁷ atoms of hydrogen
