C3H8 → CH4 + C2H4

1. Composition of substances in the reaction:

1.1. What is propane?

C3H8 is the chemical formula of Propane or gas propane. This is an open-chain, saturated hydrocarbon compound with a molar mass of 44g/mol.

At standard temperature and pressure conditions, propane exists as a gas. Furthermore, it can be compressed into liquid propane for easy transportation and storage.

Propane is a by-product of natural gas processing and oil refining. They are therefore often used as fuels for thermal applications.

C3H8 is stored and stored at the same pressure as the liquid in propane cylinders. Therefore, it is easy to return to vapor form when you release the pressure level in the air tank.

The equation to make C3H8 (Propane):

2H₂ + OLD₃H₄ → OLD₃H₈

H₂ + OLD₃H₆ → OLD₃H₈

ONLY₃Cl + 2Na + OLD₂H₅Cl → 2NaCl + OLD₃H₈

1.2. What is methane?

– In nature, methane is abundant in gas fields (natural gas), in oil fields (oil field gas), in coal mines (coal mine gas).

Methane has a molecular formula of CH₄ and molecular mass is 16 units.

Methane is a colorless, odorless, tasteless gas that is lighter than air. The density of methane to air is d_CH4/kk = 16/29. Methane is very slightly soluble in water. It liquefies at −162 °C, solidifies at −183 °C, and is highly flammable.

– Methane is an important material in life and production because when it burns it produces a large amount of heat. As the raw material to make H_2: ONLY₄ + FRIENDS₂O (t°, xt) → CO₂ + FRIENDS₂

– Methane is a raw material for the preparation of coal powder and many other substances such as methanol, acetic acid, acetic anhydride…

Equation to generate ONLY₄ (methane):

OLD + 2H₂ → ONLY₄

2NaOH + ONLY₂(COONa)₂ → ONLY₄ + 2Na₂CO₃

Catalysis: High Other conditions: high temperature

ONLY₃COONa + NaOH → ONLY₄ + Na₂CO₃

Temperature: temperature Catalysis: High

1.3. What is ethylene?

Ethylene has the molecular formula: C₂H₄ and has molecular mass: 28 unitsC

Ethylene is a gas, colorless, odorless, lighter than air and sparingly soluble in water.

Similar to methane, when burning ethylene gas, it produces CO . gas₂steam and give off a lot of heat.

– Ethylene is used to prepare acetic acid, ethyl alcohol, poly (vinyl chloride), …

– Ethylene is used to stimulate fruit ripening.

Equation to generate OLD₂H₄ (ethylene):

OLD₂H₆ → OLD₂H₄ + H₂

Temperature: 500°C Catalysis: catalysis

OLD₂H₅OH → OLD₂H₄ + H₂O

Temperature: 170°C Catalysis: H2SO4

OLD₂H₅Cl → OLD₂H₄ + HCl

Solvent: dd NaOH / C2H5OH

2. Conditions for the reaction to occur:

– High temperature.

– Catalyst: Ni, Fe, Cr₂O₃PT…

Under the effect of high heat and suitable catalyst C₃H₈ can be decomposed into ONLY₄ and C₂H₄

– Identification: Lead the product mixture obtained through the container of Bromine solution to see that the Bromine solution is pale.

3. Cracking reaction:

– The above reaction is called cracking reaction₄ and C₂H₄ The resulting product may have both₂ and C₃H₆.

– Under conditions of high temperature, pressure and catalysis, alkanes can break the C chain to form smaller alkanes and alkenes called cracking.

– Regardless of which direction the reaction takes place, the reaction does not change the mass of the mixture: m_{before reaction} = m_{after reaction}.

– The reaction always increases the number of moles of gas: n_after > n_before

– Some common cracking reactions

Butane cracking reaction C₄H_ten

When performing butane cracking reaction, a mixture of alkanes and alkenes will be obtained such as: C₄H₈H₂ONLY₄,₃H₆,₂H₆,₂H₄…

Reaction Equation:

OLD₄H_ten → OLD₄H₈+ FRIENDS₂

OLD₄H_ten→ ONLY₄ + OLD₃H₆

OLD₄H_ten → OLD₂H₆+ OLD₂H₄

OLD₄H_ten → OLD₃H₈ + ONLY₂

– Method of solving the Cracking Ankan exercise:

Under the effect of temperature, catalyst, alkanes can react in many directions:

Cracking reaction: ANKAN −^{tº, xt}→ OTHER ANKAN + ANKEN (discolors dd bromine)

Dehydrogenation reaction: ANKAN −^{tº, xt}→ ANKEN + FAMILY₂

For example:

OLD₃H₈ −^{tº, xt}→ ONLY₄ + OLD₂H₄ (ONLY₂= ONLY₂)

OLD₃H₈ −^{tº, xt}→ OLD₃H₆ (ONLY₂=CH–JUST₃) + FAMILY₂

In particular, under the right conditions, the reaction can also:

+ Generate alkines: For example: 2CH₄ −^{1500ºC, lln}→ ONLY + 3 HOURS₂

+ Generate carbon and hydrogen: Example: ONLY₄ −^{tº, xt}→ C (solid) + 2H₂

The reaction does not change the mass of the mixture:

m_{before reaction} = m_{after reaction} MOTHER_D/MOTHER_S = n_S/n_D

the content of C and H before and after the reaction is the same ⇒ the combustion of the mixture after the reaction is referred to as the combustion of the mixture before the reaction.

– The reaction always increases the number of moles of gas: n_after > n_before P_after > P_head MOTHER_tb after < CODE_tb head (because m_head = m_after)

Example:₃H₈ −^{tº, xt}→ ONLY₄ + OLD₂H₄ nsau = 2. First

– Number of moles of alkenes produced: n_alkenes = n_S – n_D; Reaction efficiency: H = (n_S– n_D)/n_D .100%

4. Related exercises and instructions:

1. Cracking₃H₈ obtain a mixture X consisting of H₂,₂H₄ONLY₄,₃H₆,₃H₈ has dX/He = 10. The reaction efficiency is:

A. 10%

B. 80%.

C. 70%.

D. 60%

Instruct.

Cracking C3H8:

C3H8

CH4 + C2H4

x x x mole

C3H8

H₂ + OLD₃H₆

y y y mol

We see in X remaining 1 part C₃H₈ not cracked yet.

USA_X = US_He.10 = 4.10 = 40 g/mol

Assume there is 1 mole of C₃H₈.

Conservation of mass has: m_before = m_after or 1.44 = nx.40 → nx = 1.1 mol

According to the high school with n_C3H8p = n_after – n_before = 1.1 – 1 = 0.1 mol

So

Answer: A

2. ONLY₄,₂H₄,₃H₆ and partially uncracked propane. Know the reaction efficiency is 90%. The average molecular mass of A is:

A. 39.6

B. 23.16

C. 2,315

D. 3.96

Instruct.

Cracking C₃H₈:

OLD₃H₈ → ONLY₄ + OLD₂H₄

OLD₃H₈ → FRIENDS₂ + OLD₃H₆

It can be seen that for every 1 mol C . loss₃H₈ will form 2 moles of product. Screen_C3H8 = 0.2 mol

Efficiency H = 90%

⇒ number of moles sp formed is: 0.2.90%.2 = 0.36 mol;

3. ONLY₄,₂H₄,₂H₆ and partially uncracked propane. Complete combustion of A yields 9 grams of H₂O and 17.6 grams of CO₂. The value of m is:

A. 4.4g

B. 6.6g

C. 8.8g

D. 11g

Instruct

The product of combustion of A is similar to that of propane

n_propane = n_H2O – n_CO2 = 9/18 – 17.6/44 = 0.1 mol

m_propane = m = 0.1.44 = 4.4 grams

Answer A.

4. The general formula of alkanes is

A. OLD_nH_n+2

B. OLD_nH_2n+2

C. OLD_nH_2n

D. OLD_nH_2n-2

_{The answer is NO}

5. Number of structural isomers corresponding to the molecular formula C₅H_twelfthTo be

A. 6

B. 4

C. 5

D. 3

Instruct:

Alkane isomers with CTPT C₅H_twelfth To be:

ONLY₃– ONLY₂– ONLY₂– ONLY₂– ONLY₃

ONLY₃-CH(ONLY₃)-ONLY₂– ONLY₃

C(ONLY₃)₄

So there are 3 isomers in all.

_{EASY ANSWER}

6. Number of structural isomers corresponding to the molecular formula C₆H₁₄ To be

A. 3

B. 4

C. 5

D. 6.

Instruct:

Write structural isomers of C₆H₁₄

ONLY₃– ONLY₂– ONLY₂– ONLY₂– ONLY₂– ONLY₃

ONLY₃-CH(ONLY₃)-ONLY₂– ONLY₂– ONLY₃

ONLY₃– ONLY₂-CH(ONLY₃)-ONLY₂– ONLY₃

(ONLY₃)₂-CH-CH(ONLY₃)₂

(ONLY₃)₃-C-ONLY₂– ONLY₃

Thus c₆H₁₄ There are 5 structural isomers.

Answer:

7. Compounds (ONLY₃)₂ONLY₂ONLY₂ONLY₃ whose name is

A. neopentan

B. 2- methylpentane

C. isopentan

D. 1,1- dimethylbutane.

Answer: REMOVE

8. Alkanes (ONLY₃)₂ONLY₂C(ONLY₃)₃ whose name is

A. 2,2,4-trimethylpentane

B. 2,2,4,4-tetramethylbutane

C. 2,4,4-trimethylpentane

D. 2,4,4,4-tetramethylbutane

Answer: A

9. Alkanes X has the molecular formula C₅H_twelfth. Chlorination of X yields 4 monochlorine derivatives. X’s name is

A. 2,2-dimethylpropane

B. 2- methylbutane

C. pentan

D. 2- dimethylpropane

Answer: REMOVE

10. Complete the following reaction diagram (write the condition of the reaction)

C3H8 -> CH4 -> C2H2 -> C2H4 -> C2H6 -> C2H5Cl

Answer:

(1) C3H8 -> C2H4 + CH4

(2) 2CH4 -> C2H2 + 2H2

(3) C2H2 + H2 -> C2H4

(4) C2H4 + H2 -> C2H6

(5) C2H6 + Cl2 -> HCl + C2H5Cl

11. Cracking butane yields 35 mol hh A consisting of ONLY₄,₂H₆H₂,₂H₄,₃H₆,₄H₈ and C₄H_ten residual. Walk A through a flask of excess bromine water and see that 20 moles of gas come out of the flask (knowing that only C₂H₄,₃H₆,₄H₈ Reaction with Br₂ and in a 1:1 molar ratio). If A is completely burned, a mole of CO . is obtained₂.