What is the heat of combustion of ethane, c2h6, in kilojoules per mole of ethane?

it's all four options.

there is none because earth is stationary and flat.

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

it's c (engineer's do their work with mechanical stuff not on any living being)