0.07g of a hydride of carbon occupies 56.0cm\(^3\) at S.T.P. When vaporized and contains 14.29% by mass of hydrogen. The formula of the hydrocarbon is(C = 12, H = 1)

olyezema

4 years ago

If the explaination was not clear let me explain it better.
first you have to look for the empirical formula......
H C
14.29/1 100 - 14.29/12
14.29 7.14
divide by the lowest value
14.29/7.14 7.14/7.14
2 1
the empirical formula = CH2
then look for the molecular formula......... but first look for the relative molecular mass
56/1000dm³ --------- 0.07g
22.4dm³. --------- 28g
or you can as well solve it in cm³
56cm³ ---------- 0.07g
22.4×1000cm³. ------- 28g
n(CH2)= 28
n(12 +1)= 28
13n= 28
n=28/13
n=2
C2H4

s.samuel

3 years ago

1 Mole of gas at stp = 22400cm³
The question says gas occupies 56cm³ at 0.07g
So we know
X = 22400cm³
0.07 = 56cm³
Cross multiply
X = 28g
I.e the molar mass = 28g
Look in the option for the one with molar mass of 28g

Which is C

Thank you

EmmanuelOlaposi061

2 years ago

A faster and better way to solve it(using stoichiometry)
mass given =0.07g
Molar mass=?
moles(n) =?
n=volume (in dm3)/molar vol
56/1000=0.056dm3
n=0.056/22.4=2.5×10^-3moles
molar mass =mass/amount
M=0.07/2.5×10^-3=28g/mol
then from the question d molar mass of option C=28

Donttouchme

1 year ago

answer typing is too closely packed.

Anela

1 year ago

Using Stoichiometry;

x g _____ 22400
0.07g____ 56
CROSS MULTIPLY ✖️

56x = 1568
DBS BY 56

x= 1568/56
= 28

( CH )n = 28
(12+2)n = 28
14n = 28

n=28/14
= 2

( CH2 )2 = C2H4

Queennette2

3 years ago

Where do you get ur 85.7 from?

xxxsurgery

7 years ago

can somebody solve this in 2min

darkypearl

11 years ago

WHERE IS 22400 GOTEN4RM

Ismaeel12345

2 years ago

the explanation is not that clear

Omobolanle234

3 years ago

its supposed to be n(12+2)=28
14n=28
n=28/14
n=2
C2H4

mercy12345678ush

2 years ago

J