Change of State - Jamb Physics Past Questions and Answers

Question 51:

• JAMB 2019

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because

A. All the heat is used to break the bonds holding the molecules of the solid together
B. The heat capacity has become very large as the substance melts
C. The heat energy is quickly conducted away
D. The heat gained is equal to the heat lost by the substance

Question 52:

• JAMB 2019

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because

A. The heat energy is quickly conducted away
B. The heat capacity has become very large as the substance melts
C. The heat gained is equal to the heat lost by the substance
D. All the heat is used to break the bonds holding the molecules of the solid together

Question 53:

• JAMB 2019

When water is boiling, it

A. Gets hotter
B. Increase is mass
C. Decreases in mass
D. Changes to steam

Question 54:

• JAMB 2020

In an experiment in which molten naphthalene is allowed to cool, the cooling curve i n the figure was obtained. The temperature 80\(^o\)C is known as the

A. Cooling temperature
B. Boiling point
C. Melting point
D. Vaporization point

Question 55:

• JAMB 2021

I. A liquid boils when its saturated vapor pressure is equal to the external pressure
II. Dissolved substances in pure water lead to an increase in the boiling point.
III. When the external pressure is increased, the boiling point increases.
IV. Dissolved substances in pure water decreases the boiling point

Which of the above combinations are peculiarities of the boiling point of a liquid?

A. I, II and III only
B. I, II, III, and IV
C. I, II, and IV
D. II, III, and IV