1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
hram777 [196]
2 years ago
7

How to draw Hess' Cycle for this question ?

Chemistry
1 answer:
NISA [10]2 years ago
7 0

Answer : The standard enthalpy of formation of ethylene is, 51.8 kJ/mole

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The formation reaction of C_2H_4 will be,

2C(s)+2H_2(g)\rightarrow C_2H_4(g)    \Delta H_{formation}=?

The intermediate balanced chemical reaction will be,

(1) C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)     \Delta H_1=-1411kJ/mole

(2) C(s)+O_2(g)\rightarrow CO_2(g)    \Delta H_2=-393.7kJ/mole

(3) H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l)    \Delta H_3=-285.9kJ/mole

Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equations, we get :

(1) 2CO_2(g)+2H_2O(l)\rightarrow C_2H_4(g)+3O_2(g)     \Delta H_1=+1411kJ/mole

(2) 2C(s)+2O_2(g)\rightarrow 2CO_2(g)    \Delta H_2=2\times (-393.7kJ/mole)=-787.4kJ/mole

(3) 2H_2(g)+2O_2(g)\rightarrow 2H_2O(l)    \Delta H_3=2\times (-285.9kJ/mole)=-571.8kJ/mole

The expression for enthalpy of formation of C_2H_4 will be,

\Delta H_{formation}=\Delta H_1+\Delta H_2+\Delta H_3

\Delta H=(+1411kJ/mole)+(-787.4kJ/mole)+(-571.8kJ/mole)

\Delta H=51.8kJ/mole

Therefore, the standard enthalpy of formation of ethylene is, 51.8 kJ/mole

You might be interested in
An enclosed vessel contains 2.5g of 9b nitrogen and 13.3g of chlorine at s.T.P. Of What will be the partial pressure of the Il n
kow [346]

Answer:

0.535 atm

Explanation:

Since the volume of the tank is constant, we use Gay- Lussac's law to find the pressure at 180°C.

So, P₁/T₁ = P₂/T₂ where P₁ = pressure at S.T.P = 1 atm, T₁ = temperature at S.T.P = 273.15 K, P₂ = pressure of gas at 180 °C and T₂ = 180 °C = 273.15 + 180 K = 453.15 K

So, P₁/T₁ = P₂/T₂

P₂ = P₁T₂/T₁

Substituting the values of the variables into the equation, we have

P₂ = P₁T₂/T₁

P₂ = 1 atm × 453.15 K/273.15 K

P₂ = 1 atm × 1.66

P₂ = 1.66 atm

We now need to find the total number of moles of each gas present

number of moles of nitrogen = mass of nitrogen, m/molar mass of nitrogen molecule M

n = m/M

m = 2.5 g and M = 2 × atomic mass of nitrogen (since it is diatomic) = 2 × 14 g/mol = 28 g/mol

So, n = 2.5 g/28 g/mol

n = 0.089 mol

number of moles of chlorine, n' = mass of chlorine, m'/molar mass of chlorine molecule M'

n' = m'/M'

m' = 13.3 g and M = 2 × atomic mass of chlorine (since it is diatomic) = 2 × 35.5 g/mol = 71 g/mol

So, n' = 13.3 g/71 g/mol

n' = 0.187 mol

So, the total number of moles of gas present is n" = n + n' = 0.089 mol + 0.187 mol = 0.276 mol

So, the partial pressure due to nitrogen gas, P = mole fraction of nitrogen × pressure of gas at 180 °C

P = n/n" × P₂

P = 0.089 mol/0.276 mol × 1.66 atm

P = 0.322 × 1.66 atm

P = 0.535 atm

8 0
3 years ago
The quantity 0.202 g has _____________________________ significant<br> figures.
andreyandreev [35.5K]
0.202g has 3 sigfigs
7 0
3 years ago
Draw the cis and trans isomers of 2-butene, ch3chchch3. show all hydrogen atoms.
RoseWind [281]
In general chemistry, isomers are two or more elements that have the same number of protons but differ in mass number. In organic chemistry, the compounds are cis or trans isomers if they have the same chemical formula, but differ in the placement of functional groups based on molecular geometry. Cis isomer is when two like functional groups are on the same side of the molecules, while trans isomer is when the like functional groups are on opposite sides. 

The cis-trans isomers are shown in the picture. As you can see, in the cis isomer, the methane functional group are both in the same side. Same as well with the hydrogen atoms. On the other hand, these functional groups are opposite to each other in the trans isomer.

4 0
3 years ago
Read 2 more answers
I need help on this fast plz
algol [13]

Answer:

the answer is 7 which is the atomic number of nitrogen

Explanation:

Al+Na=24

24/Oxygen (8) =3

3x rounded atomic mass of Ne (3x20) = 60

60+ 20 (# of neutrons in K)=80

80-30 (# of electrons in zinc)= 50

50/25 (the atomic number of Mn)=2

2x9 (number of protons in F)= 18

18+24 (atomic mass of Mg)=42

42/6 (number of neutrons in boron)=7

7 is the atomic number of Nitrogen (N)

3 0
3 years ago
Carbon 14 is an example of blank dating
Brilliant_brown [7]

Answer:

Carbon

Explanation:

It's in the name lol

6 0
3 years ago
Other questions:
  • The theoretical yield for CuCO3.Cu(OH)2+2h2SO4 ®2CuSO4+2H2O+3CO2
    11·1 answer
  • Hurry plz
    14·2 answers
  • In general, for a gas at a constant volume, _____.
    14·1 answer
  • What is the difference between intensive &amp; extensive phyiscal properties? ​
    13·1 answer
  • Examples of electromagnetic wave
    5·1 answer
  • Which two compounds are classified as bases by the Brønsted-Lowry definition, but not by the Arrhenius definition, and why?
    8·1 answer
  • In an ionic bond:
    15·2 answers
  • A mole of any atom or molecule has the same number of?
    8·2 answers
  • Pb + Fe(SO4) =Pb(SO4) + Fe what type of reaction is this ?
    9·1 answer
  • A student is investigating acceleration using balls with
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!