Atomic and Molecular Masses

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of  $\text{PbO}$ and 3.2 g of  $\mathrm{HCl}$? Molar mass of $\mathrm{PbO}$ is equal to 223 g/mol.

In the nineteenth century, scientists could determine mass of one atom relative to another by experimental methods using Avogadro's hypothesis. Earlier, hydrogen was used as the reference element being the lightest atom, but the present system of atomic masses is based on carbon-$12$ as the standard and has been agreed upon in the year _____.

In the nineteenth century, scientists used to determine the absolute mass of an atom using technique called mass spectrometry.

Discuss the need of reference element in the calculation of atomic masses.

Which element is used as a reference element in the present system of atomic masses?

What is the difference between mass number and relative atomic mass?

Carbon- _____ is the reference for all atomic mass calculations. ($10/11/12$)

Is hydrogen the standard for atomic mass?

A gas mixture contains $50\raisebox{1ex}{$ o$}\!\left/ \!\raisebox{-1ex}{$o$}\right.$ helium and $50 \raisebox{1ex}{$o$}\!\left/ \!\raisebox{-1ex}{$o$}\right.$ methane by volume. What is the percentage by weight of methane in the mixture?

$0.304 \mathrm{g}$ of a silver salt of a dibasic acid left $0.216 \mathrm{g}$ of silver on ignition. Calculate its molecular weight of the dibasic acid.

A gas mixture contains $50\%$ helium and $50\%$ methane by volume. What is the percentage by weight of methane in the mixture?

An element X has the following isotopic composition:
${}^{200}\mathrm{X}:90\raisebox{1ex}{$ \mathrm{o}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{o}$}\right.$ ,  ${}^{199}\mathrm{X}:8.0 \raisebox{1ex}{$\mathrm{o}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{o}$}\right.$ ,   ${}^{202}\mathrm{X}:2 \raisebox{1ex}{$\mathrm{o}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{o}$}\right.$
The weighted average atomic mass of the naturally occurring element X is close to

A welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives $3.38 \mathrm{g}$ carbon dioxide. $0.690 \mathrm{g}$ of water and no other products. A volume of $10.0 \mathrm{L}$ (measured at STP) of this welding gas is found to weight $11.6 \mathrm{g}$. Calculate the empirical formula.

Gram atomic mass is the mass of _____$\times {10}^{23}$ atoms of an element.

The gram atomic mass of zinc is:

Atomic mass is the number dealing with an atom, while gram atomic mass is the mass of one _____ of an atom.

Which is the correct gram molecular mass of ammonia?

Define gram molecular mass?

An _____ is the smallest unit of matter that contains all its properties.

Atomic mass of an element expressed in _____ is called its gram atomic mass or gram atoms.