All categories

3 years ago

What would you expect to observe when Br2 reacts with 2-butyne?

Chemistry

1 answer:

Nookie1986 [14]3 years ago

6 0

Answer:

I expect to observe a change in colour from reddish brown to a colourless solution

Explanation:

Bromine (Br2) attacks the electron rich carbon-carbon triple bond in but-2-yne, an alkyne to form an initial product 2, 3 dibromobut-2-ene; which reacts with excess bromine to form a final product 2,2,3,3 -tetrabromobutane.

The reaction occurs in two steps. On approaching but-2-yne, bromine molecule becomes polarised forming an induced dipole containing a bromonium ion.

Br - Br → Br+ - Br-

The bromonium ion (Br+) formed then attacks the carbon - carbon triple bond to form the initial product

2,3- dibromobut-2-ene

CH2-C≡C-CH2 + Br+ →

CH2 - CBr =CBr-CH2

(2,3- dibromobut-2-ene)

Which in the presence of excess bromine gives the final product

2,2,3,3 - tetrabromobutane.

CH2 - CBr =CBr-CH2 + Br2 →

CH3 -CBr2-CBr2 - CH3

2,2,3,3 - tetrabromobutane.

A visible change in colour from the reddish-brown colour of Bromine to a colourless solution is observed during the reaction.

You might be interested in

Indicate how the concentration of each species in the chemical equation will change to reestablish equilibrium after changing th

Viktor [21]

Explanation:

Since this is an equilibrium problem, we apply le chatelier principle. This principle states that whenever a system at equilibrium is disturbed due to change in several factors, it would move in a way to annul such change.

C2H4(g) + Cl2 ⇔ 2C2H4Cl2(g)

When the concentration of C2H4 is increased, there is more reactant sin the system. In order to annul this change, the equilibrium position will shift to the right favoring product formation.

When the concentration of C2H4Cl2 is increased, there is more product in the system. To annul this change, the equilibrium position will shift to the left, favoring reactant formation.

7 0

3 years ago

A large balloon contains 233 L of neon at 22.0C and 760. Torr. If the balloon ascends to an altitude where the temperature is -

shepuryov [24]

Answer: The volume in the balloon at the higher altitude is 260 L

Explanation:

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 760 torr

$P_2$ = final pressure of gas = 511 torr

$V_1$ = initial volume of gas = 233 L

$V_2$ = final volume of gas = ?

$T_1$ = initial temperature of gas = $22.0^0C=(22.0+273)K=295K$

$T_2$ = final temperature of gas = $-52.0^0C=(-52.0+273)K=221K$

Now put all the given values in the above equation, we get:

$\frac{760\times 233}{295}=\frac{511\times V_2}{221}$

$V_2=260L$

The volume in the balloon at the higher altitude is 260 L

3 0

3 years ago

Elements in group 1 will (lose or gain) electrons to obtain a noble gas structure. How many electrons will the element gain or l

Whitepunk [10]

Answer is: elements in group 1 will lose electrons to obtain a noble gas structure. They will lose 1 electron.
For example ₃Li 1s²2s¹ will lose one electron from 2s oribtal to obtain helium structure ₂He 1s².
Or sodium ₁₁Na 1s²2s²2p⁶3s¹ will also lose one electron to obtain neon structure ₁₀Ne 1s²2s²2p⁶.

3 0

3 years ago

Recall all the models you described in task 1. Think about the results each model would predict for Thomson’s experiment. Which

Bumek [7]

Answer:

J.J. Thomson’s experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged “soup.”

4 0

3 years ago

Please select the best answer and click "submit."

vladimir1956 [14]

When it comes to physical changes like phase changes, there are two types of heat energy: sensible heat and latent heat. Sensible heat is the heat absorbed/released when you heat the substance but it doesn't change phase. An example would be heating lukewarm water. The substance is liquid all throughout. Latent heat, on the other hand, is the heat absorbed/released when there is a phase change. An example would be boiling water, because it changes liquid to vapor.

Hence, for freezing liquid, you use the latent heat, specifically the heat of fusion. The answer should be

2.5 g * (1 mol/18.02 g) * 6.03 kJ/mol = 0.84 kJ/mol

The answer is not in the choices. You only use Hvap if you boil water.

5 0

4 years ago