Question

What is the mass of 0.5 mole of water molecule?

Answer 1

Hint: Water is an inorganic substance which is a necessity for all living organisms. The molecular mass is the mass of a molecule and water is made up of two atoms of hydrogen and one atom of oxygen so to calculate the mass of the water molecule we need to sum up the atomic masses of the atoms present. Mass of 1 mole of water is 18g.

Complete step by step answer:
Molecular mass is the mass of a given molecule. The mass of a molecule can be calculated by first determining the molecular formula of the molecule, then atomic mass of each element of the molecule is calculated and then we multiply the answer with the number of atoms of the element if given. A mole is the unit of measurement of amount of substance. It is said that a mole of a particle is given as $6.022 \times {10^{23}}$ which is the Avogadro number.

${H_2}O$ is the chemical formula for water. One molecule of water contains one oxygen and two hydrogen atoms. These atoms are connected to each other with covalent bonding. Water is an inorganic substance that is transparent, colourless and odourless. It is polar and known as the universal solvent. Water has both cohesive and adhesive properties. As we know that water is the basic necessity for living organisms, it is also used as a cooling agent in many industries. It has high heat capacity. It has applications in all three states- solid, liquid and vapour. The molecules of water have hydrogen bonding and thus, for another substance to be soluble in water molecules shall form hydrogen bond with water.

For the above given question,
We know that mass of 1 molecule of water,
${H_2}O$ with 1 oxygen and 2 hydrogen atoms is
Atomic mass of hydrogen x 2 + Atomic mass of oxygen
$ \Rightarrow 1 \times 2 + 16$
thus, mass of 1 mole of water = 18g
So, mass of 0.5 mole of water is given as
$ \Rightarrow m = 0.5 \times 18$
$ \Rightarrow m = 9g$

Mass of 0.5 mole of water is 9g.

Note:
Molecular mass is the mass of the molecule and molar mass is the mass of a mole of a substance. Water is good for healthy functioning of the human body but excessive consumption of water can lead to fluid overload in the human body which results in imbalance in the body. Also it may cause lower sodium levels in the body which may lead to vomiting and fatigue.