Mole Concept and Stoichiometry

Ozone is a molecule made of three oxygen atoms, giving it the chemical formula O3. This distinguishes it from regular oxygen which has only two oxygen atoms (O2). Ozone forms the ozone layer in the upper atmosphere.

The melting point of gallium is 27 ^oC.

The melting point of wax is 63^oC.

A molecular formula represents the actual number of atoms of each element present in one molecule of a compound, unlike an empirical formula which only shows the simplest ratio.

Pure gold is defined as 24 carats, meaning it is 100% gold by mass.

Correct answer. Among given options, 36 g of H₂O has highest number of molecules. 34 g of H₂O = 2 moles of H₂O = 2 x 6.022 x 10²³ molecules of H₂O  

54 g of H₂O = 3 moles of H₂O = 3 x 6.023 x 10²³ molecules of H₂O

Ozone is an allotrope of oxygen consisting of three oxygen atoms, hence its chemical formula is O3.

Urea is an organic compound with the chemical formula (NH2)2CO, commonly produced by the liver and excreted in urine.

The dipole moment of carbon dioxide is zero. This is because CO2 is a linear molecule in which the two C=O (m=2.3D) bonds are oriented in opposite directions at an angle of 180°. Due to the linear geometry the dipole moment of one C = O bond cancels that of another. Therefore, the resultant dipole moment of the molecule is zero and it is a non-polar molecule.

Wrought iron is a very pure form of iron with a very low carbon content, typically less than 0.08 percent, fitting within the 0.05-1 percent range.

Ans : 3.

Ans : 1.

Option 2 is correct.

Ans : 4.