The graph below compares the motion of particles in two substances. one substance is a gas and the other is a solid. a bar graph is shown with the title particle motion. the y axis title is particle speed. the x axis title is substance. there are two markings on the x axis. one is marked a and the other is marked b. the bar above a is lower than the bar above b. which statement best describes the two substances? particles are closer together in solids so substance b is a solid. particles are farther apart in solids so substance a is a solid. particles are farther apart in gases so substance b is a gas. particles are closer together in gases so substance a is a gas.

Answer is: Particles are farther apart in gases so Substance B is a gas.

For example, nitrogen molecules have weakest intermolecular bonds in gas phase and move fast and without order.  

Cooling is change from gas to solids. In solid state (for example ice) movement of molecules is more slow than movement of molecules in the gas (for example water vapor).

The process by which a solid changes directly to a gas without first becoming a liquid is called c. sublimation.

Sublimation is an endothermic process. For example dry ice (carbon(IV) oxide in solid state) is used because of sublimation in nightclubs, fog machines, at theaters, haunted house attractions.

Particles are farther apart in gases so Substance B is a gas.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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