The phase change that is the reverse of sublimation is
a. condensation.
b. melting.
c. vaporization.
d. deposition

Sublimation is the direct transition of a solid to a gas. The opposite of that is deposition which is a gas cooling an becoming a solid. D) is the correct answer.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

About 8 gallons of fuel will be used. (8.08)