Question

What is the molar mass of helium in kg/mol?

Answer 1

Hint: We know that the mass of $1mole$ of helium gas can be calculated by the relation between mass, moles and Atomic mass of Helium gas. We should remember the relation between these quantities moles is equal to the mass divided by molar mass. The formula used here is: $Moles=\dfrac{Mass}{MolarMass}.$

Complete answer:
In the given question we have given the moles of helium gas and Atomic mass of helium gas that is one and four u respectively. We have to calculate the mass of helium gas. By using the above formula we can calculate the mass of Helium gas. We have to calculate the mass of helium gas. By using the above formula we can calculate the mass of Helium gas in $kg/mol.$
Atomic mass: It is defined as the mass of an atom of a particular substance. It is also defined as the total number of neutrons and protons present in an atom known as atomic mass. Helium is a chemical element; it is an inert gas or also known as noble gas. It is a colorless, odorless and tasteless gas. Helium gas is used to insert shield or arc welding to pressurize the fuel tanks of liquid-fueled rock and in supersonic wind tunnels.
$Moles=\dfrac{Mass}{MolarMass}.$
By putting the value of given quantity we get the value of mass; $1=\dfrac{Mass}{4}.$
Therefore, mass of helium gas is $4g/mol.$
Now we have to convert grams into kilograms; So the molar mass of helium is \[~\left( 4g/mol \right)\times \left( {{10}^{-3}}kg/g~ \right)=~4\times {{10}^{-3}}\cdot kg\cdot mo{{l}^{-1}}\]

Note:
Remember that the mole is defined as of some chemical unit, be it atoms, molecules, ions, or other. The mole is a convenient unit to use because of the great number of atoms, molecules or other in any substance. The mole was originally defined as the number of atoms.