Question

Determine the molar mass for the following elements: Ca Xe Fe Au

Answer 1

Answer:

Molar mass of the following elements are :

Ca = 40.078 g/mol

Xe = 131.293 g/mol

Fe = 55.8455 g/mol

Au = 196.966 g/mol

Explanation:

Molar Mass  = It is the mass of 1 mole of a particular atom.

• Mass of 1 mole of substance measured in grams is called molar mass.

• It is calculated by adding atomic masses of the constituent atoms(g/mol)
• In given elements only 1 atom is present so atomic mass = molar mass
• Atomic mass of Ca = 40.078 amu , molar mass 40.078 g/mol
• Atomic mass of Xe = 131.29 amu, molar mass = 131.29 g/mol
• Atomic mass of Fe = 55.84 amu , molar mass = 55.84 g/mol

Look at the following point :

Atomic mass : It is the mass of single atom . It is the sum of masses of the subatomic particles(proton , neutron and electron) present in the atom. It is exactly equal to 1/12 of mass of C-12 atom.

Atomic mass is expressed in amu.

Mole =  It is the quantity which represent the amount of particle present in 12 gram of C-12.

Atomic mass(amu) into grams:

1 gram of C-12 = 12 atoms of C

$= 1.9929\times 10^{-23}$

mass of 1 atom of C =

$=\frac{1}{12}1.9929\times 10^{-23}$

$= 1.66\times 10^{-24}$ gram

So , 1 amu =  

$= 1.66\times 10^{-24}$ gram