Chapter U1.26, Problem 10E

Interpretation Introduction

(a)

Interpretation:

Solubility of calcium has to be predicted and explained.

Concept introduction:

From the periodic table, one can find out the type of bonding present in substances by knowing whether the compound is made of metals or nonmetals or both. Metallic bonding is present between atoms of metals.

Answer to Problem 10E

Calcium, Ca is a metal. It will not dissolve in water.

Explanation of Solution

Calcium has metallic bonding with valence electrons free to move throughout the substance. There is a strong force of attraction between the positively charged atoms and negatively charged sea of electrons. So calcium atoms cannot dissolve in water.

Interpretation Introduction

(b)

Interpretation:

Solubility of NaNO₃has to be predicted and explained.

Concept introduction:

Ionic compounds are formed between metals and nonmetals. These compounds have ionic bonds in them. NaNO₃is an ionic compound as it has sodium metal and nitrogen and oxygen nonmetals.

Answer to Problem 10E

Sodium nitrate, NaNO₃ is an ionic compound so it will dissolve in water.

Explanation of Solution

Sodium nitrate has ionic bonding between sodium ions and nitrate ions. In water, these ions dissociate and so the compound dissolves in water.

(c)

Interpretation Introduction

Interpretation:

Solubility of silicon has to be predicted and explained.

Concept introduction:

In network covalent bonding the charge cannot move as the electrons are stuck between the atoms and are not available to move.

Answer to Problem 10E

Silicon, Si is a nonmetal. It has network covalent bonding so it is not soluble in water.

Explanation of Solution

Silicon has network covalent bonding so it will settle down in water. It will not dissolve in water as the electrons are not free to move.

(d)

Interpretation Introduction

Interpretation:

Solubility of CH₄has to be predicted and explained.

Concept introduction:

Methane is a gas with molecular covalent bonding. This bond allows atoms to share valence electrons between them.

Answer to Problem 10E

Methane, CH₄ has molecular covalent bonding so it is soluble in water.

Explanation of Solution

Methane is a gas made of nonmetals carbon and hydrogen. It has molecular covalent bonding due to which the atoms share valence electrons between them. The molecules of methane scatter amongst the molecules of water and so they are soluble in water.

(e)

Interpretation Introduction

Interpretation:

Solubility of CuSO₄has to be predicted and explained.

Concept introduction:

Ionic compounds are formed between metals and nonmetals. These compounds have ionic bonds in them. NaNO₃is an ionic compound as it has sodium metal and nitrogen and oxygen nonmetals.

Answer to Problem 10E

Copper sulfate, CuSO₄ is an ionic compound so it is soluble in water.

Explanation of Solution

Copper sulfate has ionic bonding between copper ions and sulfate ions. In water, these ions dissociate and so the compound dissolves in water.