Mr(CH4) = 12 + 1*4 = 16
Mr(C2H6) = 12*2 + 1*6 = 30
Mr(C3H8) = 12*3 + 1*8 = 44
Mr(C4H10) = 12*4 + 1*10 = 58
Mr(C5H12) = 12 *5 + 1*12 = 72
Mr(C6H14) = 12*6 + 1*14 = 86
Mr(C7H16) = 12*7 + 1*16 = 100
Mr(C8H18) = 12*8 + 1*18 = 114
Mr(C9H20) = 12*9 + 1*20 =128
Mr(C10H22) = 12*10 + 1*22 = 142
Mr(CH4) = 12 + 1*4 = 16
Mr(C2H6) = 12*2 + 1*6 = 30
Mr(C3H8) = 12*3 + 1*8 = 44
Mr(C4H10) = 12*4 + 1*10 = 58
Mr(C5H12) = 12 *5 + 1*12 = 72
Mr(C6H14) = 12*6 + 1*14 = 86
Mr(C7H16) = 12*7 + 1*16 = 100
Mr(C8H18) = 12*8 + 1*18 = 114
Mr(C9H20) = 12*9 + 1*20 =128
Mr(C10H22) = 12*10 + 1*22 = 142