Which energy change takes place when gasoline evaporates from a fuel gas can?
a. energy is released.
b. energy is absorbed.
c. energy remains stationary.
d. energy becomes transformed.

B. Energy is absorbed.

Explanation: When gasoline evaporates, it changes from liquid state to gaseous state. Thus energy has to be supplied to break the intermolecular forces of attraction prevailing among liquid particles.

Endothermic reactions are those reactions in which energy is absorbed by the system. Exothermic reactions are those reactions in which energy is released by the system.

As energy is absorbed, this is an example of endothermic reaction.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .