Help pleaseee find the molecular formula of a compound with a molar mass of 70.0 g/mol and an empirical formula of CH2.

In order to find the molecular formula from an empirical formula you must find the ratio of their molecular masses.

We know that the molecular mass of the molecule is 70

gmol-1

. We can calculate the molar mass of

CH2

from the periodic table:

C=12.01

gmol−1

H=1.01

gmol−1

CH2 =14.03

gmol−1

Hence we can find the ratio:

14.03

70

≈

0.2

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.