Which of the following examples illustrates an object with kinetic energy?

What change would you expect on the rate of theSN2 reaction of 1-iodo-2-methylbutane withcyanide ion if the nucleophile concentr

Ivenika [448]

Answer:

The reaction rate of the both questions remain unchanged.

Explanation:

For question 1: The reaction 1-iodo -2- methylbutane with cyanide ion is an SN2 reaction because the Alkyl halide is a primary alkyl halide. The rate of reaction is dependent on concentration of the nucleophile and the alkyl halide at the same. For the rate of reaction to be affected (increased or decreased), the concentration of nucleophile and the alkyl halide have to be altered.

For question 2: The reaction of 2-iodo -2- methylbutane with ethanol is an SN1 reaction because the Alkyl halide is a tertiary alkyl halide. There are two-step reaction mechanism in this reaction. The first step is the rate determining step which determines the extent of the reaction and hence the rate of reaction. For the rate of reaction to be affected (increased or decreased), the concentration of the Alkyl halide alone will be altered. The rate of reaction is independent of the concentration of the nucleophile.

6 0

3 years ago

Calculate the heat change in calories for melting 65 g of ice at 0 ∘c.

Genrish500 [490]

When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:

q = m * ΔHf

the mass of ice m = 65 g

the heat of fusion of water at 0C = ΔHf = 334 J/g

Therefore: q = 65 g * 334 J/g = 21710 J

Now:

4.184 J = 1 cal

which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal

Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)

5 0

3 years ago

Calculate the osmotic pressure associated with 50.0 g of an enzyme of molecular weight 98 g/mol dissolved in water to give 2600

andrew-mc [135]

Answer:

π = 4,882 atm

Explanation:

To calculate the osmotic pressure (π), the Van´t Hoff equation must be used, which is:

π x V = n x R x T

Where:

• π: Osmotic pressure, which is the difference between the levels of the solution and the pure solvent through a semipermeable membrane, which allows the passage of the solvent but not the solute

• V: Volume of the solution, in liters unit

• n: Number of moles of solute

• R: Constant of ideal gases, equal to 0.08206 L.atm / mol.K

• T: Absolute temperature, in Kelvin degrees

With the data you provide you can calculate the osmotic pressure by clearing it from the equation, we would be equal to:

π = (n x R x T) / V

However, all data must first be converted to the corresponding units in order to replace the values in the equation.

Solution volume ⇒ go from mL to L: 

1000 mL of solution ____ 1 L

2600 mL of solution _____ X = 2.6 L

Calculation: 2600 mL x 1 L / 1000 mL = 2.6 L

Temperature ⇒ Go from ° C to K 

T (K) = t (° C) + 273.15 = 30.0 ° C + 273.15 = 303.15 K

Number of moles of solute ⇒ It can be calculated since we have the mass of the enzyme and its molecular mass:

98.0 g of enzyme ____ 1 mol

50.0 g of enzyme _____ X = 0.510 moles

Calculation: 50.0 g x 1 mol / 98.0 g = 0.510 moles

Now, you can replace the values in the Van´t Hoff equation and you will get the result:

π = (n x R x T) / V

π = (0.510 mol x 0.08206 L.atm / mol.K x 303.15 K) / 2.6 L = 4.882 atm

Therefore, the osmotic pressure will be 4,882 atm

3 0

3 years ago

The variables _______ and ________ affect the gravitational force between objects.

anastassius [24]

I think the answer is A

5 0

3 years ago

Read 2 more answers

Which of the following actions would cause the volume of the chamber below to increase to 36.0 L?

Orlov [11]

Answer:

Option C. Triple the number of moles

Explanation:

From the ideal gas equation:

PV = nRT

Where:

P is the pressure

V is the volume

n is the number of mole

R is the gas constant

T is the absolute temperature.

Making V the subject of the above equation, we have:

PV = nRT

Divide both side by P

V = nRT / P

Thus, we can say that the volume (V) is directly proportional to both the number of mole (n) and absolute temperature (T) and inversely proportional to the pressure (P). This implies that and increase in either the number of mole, the absolute temperature and a decrease in the presence will cause the volume to increase.

Thus, the correct option is option C triple the number of moles. This can further be seen as illustrated below:

Initial volume (V1) = 12 L

Initial mole (n1) = 0.5 mole

Final mole (n2) = triple the initial mole = 3 × 0.5 = 1.5 mole

Final volume (V2) =?

From:

V = nRT / P, keeping T and P constant, we have:

V1/n1 = V2/n2

12/0.5 = V2/1.5

24 = V2/1.5

Cross multiply

V2 = 24 × 1.5

V2 = 36 L.

Thus Option C gives the correct answer to the question.

5 0

3 years ago