Which of the following statements is/are correct?
i.The molar mass of carbon-12 is exactly 12 g.
ii.The phrase "molar mass of chlorine" is ambiguous.
iii.The molar mass of a substance is the mass in grams of 6.02 × 10²³ particles of that substance.
iv.For atoms,molar mass is numerically equal to atomic mass.
v.The molar masses of elements are always greater,numerically,than the atomic masses of those elements.

Question

Quizplus · Accepted Answer

i. is correct, as carbon-12 is the reference isotope for measuring atomic masses and its mass is defined as exactly 12 atomic mass units (or Dalton).
ii. is also correct as chlorine has several isotopes with different atomic masses, so the term "molar mass of chlorine" should specify which isotope or mixture of isotopes is considered.
iii. is correct, as the definition of molar mass is the mass of one mole of particles, which is a fixed number (Avogadro's number) of particles.
iv. is correct, as the molar mass of an element (or molecule) is obtained by summing the atomic masses (or molecular masses) of its component atoms (or molecules), and since the atomic mass unit is defined as 1/12 of the mass of a carbon-12 atom, the molar mass is numerically equal to the atomic (or molecular) mass in g/mol.
v. is incorrect, as the molar masses of elements are numerically equal or slightly lower than their atomic masses, due to isotopic composition and the fact that the atomic mass unit is not exactly 1 g/mol.

Which of the Following Statements Is/are Correct