Chapter 2, Problem 66E

Interpretation Introduction

(a)

Interpretation:

Whether the statement, “The fact that paper burns is a physical property” is true or false is to be stated.

Concept introduction:

Physical change is the change in the shape or size of a substance, without causing the change in its chemical identity. Chemical change is the change when a substance loses its chemical identity and forms a new substance.

Answer to Problem 66E

The statement, “The fact that paper burns is a physical property” is false.

Explanation of Solution

Burning of a paper is a chemical change and the process is known as combustion. On burning, paper loses its identity and changes into ash.

Therefore, the statement, “The fact that paper burns is a physical property” is false.

Conclusion

The statement, “The fact that paper burns is a physical property” is false.

Interpretation Introduction

(b)

Interpretation:

Whether the statement, “Particles of matter are moving in gases and liquids, but not solids” is true or false is to be stated.

Concept introduction:

Solids, liquids and gases are made up of particles that move around their fixed positions or among one another. Particles in solid are tightly packed, so they have restricted movement.

Answer to Problem 66E

The statement, “Particles of matter are moving in gases and liquids, but not solids” is false.

Explanation of Solution

In solids, the particles move by shaking or vibrating at fixed positions relative to one another. The movement of the particles among one another is restricted.

Therefore, the statement “Particles of matter are moving in gases and liquids, but not solids” is false.

Conclusion

The statement, “Particles of matter are moving in gases and liquids, but not solids” is false.

Interpretation Introduction

(c)

Interpretation:

Whether the statement, “A heterogeneous substance has a uniform appearance throughout” is true or false is to be stated.

Concept introduction:

Homogeneous substance is a mixture of two or more pure substances which mix completely with one another and has uniform composition and appearance throughout. Heterogeneous substance is a mixture of two or more substances which do not mix completely with one another and do not have uniform composition or appearance throughout.

Answer to Problem 66E

The statement, “A heterogeneous substance has a uniform appearance throughout” is false.

Explanation of Solution

Heterogeneous substance is a mixture of two or more substances which do not mix completely with one another and do not have uniform composition or appearance throughout.

Therefore, the statement, “A heterogeneous substance has a uniform appearance throughout” is false.

Conclusion

The statement, “A heterogeneous substance has a uniform appearance throughout” is false.

Interpretation Introduction

(d)

Interpretation:

Whether the statement, “Compounds are impure substances” is true or false is to be stated.

Concept introduction:

Compounds are made up of two or more elements which are chemically bonded. A compound has a pattern of repeating units of two or more elements which have same fixed composition throughout. Such compounds are known as pure compounds.

Answer to Problem 66E

The statement, “Compounds are impure substances” is false.

Explanation of Solution

Compounds can be pure substances like water, the composition of hydrogen and oxygen is same throughout.

Therefore, the statement, “Compounds are impure substances” is false.

Conclusion

The statement, “Compounds are impure substances” is false.

Interpretation Introduction

(e)

Interpretation:

Whether the statement, “If one sample of sulfur dioxide is $50\%$ sulfur and $50\%$ oxygen, then all samples of sulfur dioxide are $50\%$ sulfur and $50\%$ oxygen” is true or false is to be stated.

Concept introduction:

Law of Definite Composition states that, “Any compound is made up of elements in the same proportion by mass (weight).” Compounds have definite composition throughout.

Answer to Problem 66E

The statement, “If one sample of sulfur dioxide is $50\%$ sulfur and $50\%$ oxygen, then all samples of sulfur dioxide are $50\%$ sulfur and $50\%$ oxygen” is true.

Explanation of Solution

Sulfur and oxygen combines in a definite proportion by mass, according to Law of Definite Composition. Sulfur dioxide is made up of one atom of sulfur and two atoms of oxygen. This atom ratio is fixed and the atoms have fixed weight, so the ratio of weights in a compound is also fixed.

Therefore, the statement, “If one sample of sulfur dioxide is $50\%$ sulfur and $50\%$ oxygen, then all samples of sulfur dioxide are $50\%$ sulfur and $50\%$ oxygen” is true.

Conclusion

The statement, “If one sample of sulfur dioxide is $50\%$ sulfur and $50\%$ oxygen, then all samples of sulfur dioxide are $50\%$ sulfur and $50\%$ oxygen” is true.

Interpretation Introduction

(f)

Interpretation:

Whether the statement, “A solution is a homogeneous mixture” is true or false is to be stated.

Concept introduction:

Solution is a mixture of a solute and a solvent which dissolve in each other in uniform composition and appearance. A solute is the substance which is present in a small quantity. A solvent is the substance in which the solute dissolves. Alcohol and water is a solution which appears same throughout and has same composition throughout.

Answer to Problem 66E

The statement, “A solution is a homogeneous mixture” is true.

Explanation of Solution

Mixtures are classified as homogeneous mixtures and heterogeneous mixtures. Homogeneous mixtures have uniform composition throughout. Heterogeneous mixtures do not have uniform composition and appearance.

Therefore, the statement, “A solution is a homogeneous mixture” is true.

Conclusion

The statement, “A solution is a homogeneous mixture” is true.

Interpretation Introduction

(g)

Interpretation:

Whether the statement, “Two positively charged objects attract each other, but two negatively charged objects repel each other” is true or false is to be stated.

Concept introduction:

Matter has a physical property known as electric charge. It is of two types: positive and negative charges. Like charges repel each other while opposite charges attracts each other.

Answer to Problem 66E

The statement, “Two positively charged objects attract each other, but two negatively charged objects repel each other” is false.

Explanation of Solution

Two positively or negatively charged objects always repel each other, which means, like charges repel reach other.

Therefore, the statement, “Two positively charged objects attract each other, but two negatively charged objects repel each other” is false.

Conclusion

The statement, “Two positively charged objects attract each other, but two negatively charged objects repel each other” is false.

Interpretation Introduction

(h)

Interpretation:

Whether the statement, “Mass is conserved in an endothermic chemical change but not in an exothermic chemical change” is true or false is to be stated.

Concept introduction:

Albert Einstein gave the relation between mass and energy of the system. The expression is, $\text{E}={\text{mc}}^{\text{2}}$. This expression is known as Law of Conservation of Mass and Energy. Law of Conservation of Mass states that, “The total mass of the reactants in a chemical change is equal to the total mass of the products.”

Answer to Problem 66E

The statement, “Mass is conserved in an endothermic chemical change but not in an exothermic chemical change” is false.

Explanation of Solution

According to the Law of mass, “The total mass of the reactants in a chemical change is equal to the total mass of the products.” It is irrespective of the type of chemical change taken place.

Therefore, the statement, “Mass is conserved in an endothermic chemical change but not in an exothermic chemical change” is false.

Conclusion

The statement, “Mass is conserved in an endothermic chemical change but not in an exothermic chemical change” is false

Interpretation Introduction

(i)

Interpretation:

Whether the statement, “Potential energy can be related to positions in an electrical field” is true or false is to be stated.

Concept introduction:

Potential energy is the energy of the system due to the arrangement of negatively and positively charged particles in a system Each atom consists of several small charged particles: positive and negative which when brought closer, increases the potential energy of the system.

Answer to Problem 66E

The statement, “Potential energy can be related to positions in an electrical field” is true.

Explanation of Solution

Potential energy is related to the position of charged particles in a system. When like charge particles are brought closer to each other and unlike charge particles are taken away from each other, then the potential energy of the system increases.

Therefore, the statement, “Potential energy can be related to positions in an electrical field” is true.

Conclusion

The statement, “Potential energy can be related to positions in an electrical field” is true.

Interpretation Introduction

(j)

Interpretation:

Whether the statement, “Chemical energy can be converted to kinetic energy” is true or false is to be stated.

Concept introduction:

Law of Conservation of Energy states that, “Energy of the system remains conserved in a chemical reaction. It can neither be created nor be destroyed.”

Answer to Problem 66E

The statement, “Chemical energy can be converted to kinetic energy” is true.

Explanation of Solution

In a chemical reaction, the energy of the system remains conserved. It can be transformed from one form of energy to another.

Therefore, the statement, “Chemical energy can be converted to kinetic energy” is true.

Conclusion

The statement, “Chemical energy can be converted to kinetic energy” is true.

Interpretation Introduction

(k)

Interpretation:

Whether the statement, “Potential energy is more powerful than kinetic energy” is true or false is to be stated.

Concept introduction:

Potential energy is the energy related to the arrangement of positively and negatively charged particles in a system. Kinetic energy is the energy because of the movement of charges.

Answer to Problem 66E

The statement, “Potential energy is more powerful than kinetic energy” is false.

Explanation of Solution

Potential energy and Kinetic energy are independent of each other. Kinetic energy depends upon the motion of the charges and the Potential energy depends upon the relative position of the charges to one another.

Therefore, the statement, “Potential energy is more powerful than kinetic energy” is false.

Conclusion

The statement, “Potential energy is more powerful than kinetic energy” is false.

Interpretation Introduction

(l)

Interpretation:

Whether the statement, “A chemical change always destroys something and always creates something” is true or false is to be stated.

Concept introduction:

A chemical change is the change that brings the change in the substance chemically. The properties of the substances are completely changed before and after the chemical changes takes place.

Answer to Problem 66E

The statement, “A chemical change always destroys something and always creates something” is true.

Explanation of Solution

For a chemical change to take place, the properties of a substance has to be changed before and after the change. A substance loses its chemical properties, that is, it is destroyed and a new substance is created with different chemical properties.

Therefore, the statement, “A chemical change always destroys something and always creates something” is true.

Conclusion

The statement, “A chemical change always destroys something and always creates something” is true.