Introduction：练习题

What name is given to the change of state when a gas turns directly into a solid without becoming a liquid first?

Which of the following pairs of compounds are structural isomers of each other?

An organic compound has the molecular formula \(C_6H_{12}O_6\) . What is the empirical formula of this compound?

Which of the following terms is used to describe the substance that is dissolved in a solvent to form a solution?

A student has a sample of a pure substance and a sample of a mixture. Which statement correctly describes how to distinguish between them using their melting points?

a) Describe the arrangement and movement of particles in a solid.
b) Describe the arrangement and movement of particles in a liquid.
c) Describe the arrangement and movement of particles in a gas.
d) Explain, in terms of particle movement, why a gas diffuses much faster than a liquid.

A student investigates the thermal behavior of a pure liquid substance, Substance Z, by measuring its temperature while heating it steadily until it completely vaporizes.

a) State the term used to describe the change of state from liquid to gas for Substance Z at a fixed temperature.

b) Explain, in terms of particle energy and forces of attraction, why the temperature of Substance Z remains constant while it is changing from a liquid to a gas, even though the student continues to supply heat energy.