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3 years ago

Why is acetic anhydride added slowly to a dichloromethane solution of the other reactants?

2 answers:

8 0

Acetic anhydride is the only monocarboxylic acid anhydride which is an acylating agent capable of modifying reactions. The dichloromethane is the reaction solvent.

The acetic anhydride should be added slowly through a separatory funnel to other reactants so as to avoid a runaway reaction, also known as thermal runaway. By doing this the reaction mixture boils as gently as possible while stirring. This phenomenon occurs in situations where an increase in temperature changes the conditions in a way that leads to destructive result brought about by a further increase in temperature.

creativ13 [48]3 years ago

8 0

Acetic Acid is considered one of the excellent source of Acyl (CH₃CO-) group. It is also one of the the most reactive derivative of Carbonyl groups.

As we know that the bond formation is an Exothermic reaction. Greater the rate of formation of new bonds greater will be the amount of heat released.

Hence, Acetic Anhydride being more reactive will produce more heat on reaction with other reactants and generates more heat. In order to prevent the reaction mixture from bursting the reaction is often carried out at lower temperatures and also the rate of addition of Acetic Anhydride is slowed down.

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To find the number of atoms look at the number known as the________. Please help.

Rufina [12.5K]

Answer:

molar mass or AMU

Explanation:

4 0

2 years ago

The ground state electron configuration of Fe is what

Sindrei [870]

Answer:

Iron?

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3 0

2 years ago

The lattice energy of a salt is related to the energy required to separate the ions. For which of the following pairs of ions is

Kay [80]

Answer: The Lattice energy is the energy required to separate an ionic solid into its component gaseous ions or

It is the energy released when gaseous ions combine to form an ionic solid.

Explanation:

The lattice energy depends on the ionization energies and electron affinities of atoms involved in the formation of the compound. The ionization energies and electron affinities also depends on the ionic radius and charges of the ions involved. As the ionic radius for cations increases down the groups, ionization energy decreases, whereas, as ionic radii decreases across the periods , ionization energy increases. The trend observed for anions is that as ionic radii increase down the groups, electron affinity decreases. Across the period, as ionic radii increases electron affinity increases. Also, as the charge on the ion increases, it leads to an increase in energy requirement/content.

Therefore, for compounds formed from cations and anions in the same period, the highest charged cation and anion will have the highest lattice energy. For example, among the following compounds: Al2O3 (aluminium oxide), AlCl3 (aluminium chloride), MgO, MgCl2 (magnesium chloride), NaCl, Na2O (sodium oxide); Al2O3(aluminium oxide) will have the highest lattice energy, thus will be hardest to break apart because its ions have the highest charge.

5 0

3 years ago

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

Fittoniya [83]

Answer:

a) Pf = 689.4 bar

b) P = 226.6 bar

c) T = 269.99 K

Explanation:

The molar volume of ice is equal to:

Vi = m/p = (18.02x10^-3 kg H2O/1 mol H2O)*(1 m^3/920 kg) = 1.96x10^-5 m^3 mol^-1

The molar volume of liquid water is equal to:

Vl = (18.02x10^-3 kg/1 mol)*(1 m^3/997 kg) = 1.8x10^-5 m^3 mol^-1

The change in volume is equal to:

ΔVchange = Vi-Vl = 1.96x10^-5 - 1.8x10^-5 = 1.5x10^-6 m^3 mol^-1

using the Clapeyron equation:

Pf = Pi + ((ΔHf*ΔT)/(ΔVf*Ti)) = 1.013x10^5 Pa + ((6010 J mol^-1 * 4.7 K)/(1.5x10^-6 * 273.15 K)) = 6.89x10^7 Pa = 689.4 bar

For the pressure we will use the equation:

P = (m*g)/A, where m is the mass, g is the acceleration of gravity and A is the area. Replacing values:

P = (79 kg * 9.81 m s^-2)/(1.9x10^-4 m * 0.18 m) = 2.26x10^7 Pa = 226.6 bar

From Clapeyron´s expression we need to clear ΔT:

ΔT = ((Pf-Pi)*ΔV*Ti)/ΔHf = ((2.26x10^7 - 6.89x10^7)*1.5x10^-6*273.15)/6010 = -3.16 K

you can evaluate the new melting point of ice:

T = Ti + ΔT = 273.15 K - 3.16 K = 269.99 K

4 0

3 years ago

To what temperature in kelvin will a 2.3 L balloon have to be heated to expand to a volume of 400 L Assume the initial temperatu

olchik [2.2K]

Answer:

T₂ = 51826.1 K

Explanation:

Given data:

Initial Volume = 2.3 L

Final volume = 400 L

Initial temperature = 25 °C (25+ 273 = 298 K)

Final temperature = ?

Solution:

V₁/T₁ = V₂/T₂

T₂ = V₂ T₁/V₁

T₂ = 400 L . 298 K / 2.3 L

T₂ = 119200 K. L / 2.3 L

T₂ = 51826.1 K

7 0

3 years ago