2. An alkane has a relative molecular mass of 58, determine its molecular formula.

C4H10.

Explanation:

The general formula for an alkane is CnH(2n+2).

C = 12 and H = 1  (Molecular masses).

So we have the equation:

12n + 2n + 2 = 58

14n = 56

n = 4.

So the formula is  

C4H(2*4+2)

= C4H10.

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