<span>the molar mass of a compound is the sum of the products of the atomic masses by the number of atoms of the element.
molar mass of Na</span>₂SO₄<span> is - 142 g/mol.
1 mol of </span>Na₂SO₄<span> has a mass of 142 g.
In 1 mol of </span>Na₂SO₄<span> the mass of Na is 23 g/mol x 2 = 46 g.
Mass of Na in 1 mol of </span>Na₂SO₄ is - 46 g
mass of Na in 0.820 mol of Na₂SO₄ - 46 g /1 mol x 0.820 mol = 37.72 g.
mass of Na is 37.72 g
<u><em>on the basis of the reaction of heat in plastic , their are two types of plastics : </em></u>
<h2><u>
<em>Thermoplastic & Thermosetting plastics </em></u></h2>
<u><em>Thermoplastics : Plastics which easily get deformed (become soft )on heating and also get bend easily are known as thermoplastics . </em></u>
<u><em>examples : polythene , polyvinyl chloride and polystyrene .</em></u>
<u><em>thermosetting plastics : plastics which once moulded into a shape do not become soft on heating and cannot be moulded again are called thermosetting plastics .</em></u>
<u><em>examples : bakelite , melamine and formica</em></u>
The atom that is made up of two protons is He. The number of neutrons is also two. The number of electrons matters in the charge. So to make 10 electrons, we add 8 more. hence, 4/2 He 8-.
