Chapter 14, Problem 12A

Interpretation Introduction

Interpretation: The unusual property of ice floating in liquid water has to be explained.

Concept introduction: The measure of mass per unit volume of a substance is called as density. Density is given by the formula,

  $Density=\frac{Mass}{Volume}$

The density of solids is higher than liquids and gases because the molecules in solids are tightly/closely packed.

An object that has a higher density than the fluid, the object could sink. If the object has lower density, it could float.

Answer to Problem 12A

The density of ice is lesser than that of liquid water and hence, it floats. This is unusual because an object with higher density would sink nevertheless; ice is one of the few exceptions.

Explanation of Solution

The measure of mass per unit volume of a substance is called as density. Density is given by the formula,

  $Density=\frac{Mass}{Volume}$

The density of solids is higher than liquids and gases because the molecules in solids are tightly/closely packed.

An object that has a higher density than the fluid, the object could sink. If it has lower density, it could float.

The ice floats on liquid water because in the solid state (ice), the intermolecular forces lead to a highly ordered structure but loose structure, in which each atom of oxygen is attached to four atoms of hydrogen. Two of these hydrogen atoms are covalently bonded to the atom of oxygen and the remaining two hydrogen (at longer distances) are bonded to the unshared pairs of electrons in the oxygen atom. This open structure of ice cause it to be less dense than that of the liquid state, where the ordered structure is moderately broken down and the molecules of liquid water are closer together. Due to the less density of ice, it would float in liquid water.

Conclusion

Generally, solids have higher density and they would sink but ice is one of the few exemptions because the density of ice is less than that of liquid water and therefore, it would float in liquid water.