A certain first-order reaction has a rate constant of 2.75 10-2 s−1 at 20.°c. what is the value of k at 45°c if ea = 75.5 kj/mol? webassign will check your answer for the correct number of significant figures. 0.0352 incorrect: your answer is incorrect.

Answers

Answer 1

Answer:

With an activation energy $($E_a$)$ of 75.5 kJ/mol, the rate constant k for a first-order reaction at 20°C is 2.75 × 10⁻² s⁻¹. At 45°C, k is approximately 0.095 s⁻¹, determined using the Arrhenius equation.

The Arrhenius equation relates the rate constant k, temperature T, activation energy $($E_a$)$ , and the gas constant R:

$k = Ae^{-(E_a)/(RT)}$

Given that $k_1 = 2.75 * 10^(-2) \, \text{s}^(-1)$ at $T_1 = 20^\circ \text{C} = 293.15 \, \text{K}$ and $E_a = 75.5 \, \text{kJ/mol}$ , we want to find $k_2$ at $T_2 = 45^\circ \text{C} = 318.15 \, \text{K}$ .

First, let's find the value of A using the Arrhenius equation at T_1:

$2.75 * 10^(-2) = A e^{-((75.5 * 10^3))/((8.314)(293.15))}$

Solving for A:

$A \approx 3.65 \, \text{s}^(-1)$

Now, use the Arrhenius equation at $T_2$ to find $k_2$ :

$k_2 = (3.65) e^{-((75.5 * 10^3))/((8.314)(318.15))}$

Calculate $k_2$ .

$k_2 \approx 0.095 \, \text{s}^(-1)$

Therefore, the value of k at $45^\circ \text{C}$ is approximately $0.095 \, \text{s}^(-1)$ .

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Answer 2

Answer:

Final answer:

To find the new rate constant of a first-order reaction under different temperature conditions, we can use the Arrhenius equation, which relates the rate constant, activation energy, and temperature of a reaction.

Explanation:

The student is interested in finding the value of the rate constant (k) at a different temperature for a first-order reaction. The answer can be found using the Arrhenius equation, which defines the relationship between the rate constant (k) of a reaction and the temperature at which the reaction occurs. The activation energy (Ea) is also necessary.

The Arrhenius equation is: k = A * exp(-Ea/(R*T)), where A is the pre-exponential factor, R is the universal gas constant (the value of R should be 8.314 J/mol.K to match the Ea units), and T is the temperature in Kelvin.

At the first condition, you have the value of k and the corresponding T (convert Celsius to Kelvin by adding 273.15). With these values and the known Ea, you can solve for A. Then, using the value of A, Ea, and the second T (also converted to Kelvin), you can solve for the new k.

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What is the mass of 0.73 moles of AgNO3?

Answers

Answer:

124 g (3 sig figs)

124.011 g (6 sig figs

Explanation:

Step 1: Calculate g/mol for AgNO₃

Ag - 107.868 g/mol

N - 14.01 g/mol

O - 16.00 g/mol

107.868 + 14.01 + 16.00(3) = 169.878 g/mol

Step 2: Multiply 0.73 moles by molar mass

0.73 mol (169.979 g/mol)

124 grams of AgNO₃

How many moles of carbondioxide are produced when 0.2mol of sodium carbonate react with excess hydrovhloric acid

Answers

Answer:

0.2 moles of CO₂ are produced

Explanation:

Given data:

Moles of CO₂ produced = ?

Moles of Na₂CO₃ react = 0.2 mol

Solution:

Chemical equation:

Na₂CO₃ + 2HCl → 2NaCl + CO₂ + H₂O

Now we will compare the moles of CO₂ with Na₂CO₃ .

Na₂CO₃ : CO₂

1 : 1

0.2 : 0.2

Thus, 0.2 moles of CO₂ are produced.

Which of the following required Bohr's model of the atom to need modification ? A. Energies of electrons are quantized. B. Quantized electron energies are responsible for emission spectra lines. C. An electron's energy increases the farther it moves from the nucleus. D. Electrons do not follow circular orbits around the nucleus..

Answers

Answer:

Electrons do not follow circular orbits around the nucleus

Explanation:

Bohr's model of the atom is a combination of elements of quantum theory and classical physics in approaching the problem of the hydrogen atom. According to Neils Bohr, stationary states exist in which the energy of the electron is constant. These stationary states were referred to as circular orbits which encompasses the nucleus of the atom. Each orbit is characterized by a principal quantum number (n). Energy is absorbed or emitted when an electron transits between stationary states in the atom.

Sommerfeld improved on Bohr's proposal by postulating that instead of considering the electron in circular orbits, electrons actually orbited around the nucleus in elliptical orbits, this became a significant improvement on Bohr's model of the atom until the wave mechanical model of Erwin Schrödinger was proposed.

Answer:

Electrons do not follow circular orbits around the nucleus

Explanation:

5. The partition coefficient of Compound A is 7.5 in dichloromethane (a.k.a. methylene chloride) with respect to water. a. If 5 grams of Compound A were dissolved in 100 mL of water, how much of Compound A would be extracted with four 25-mL portions of dichloromethane

Answers

Answer:

4.93g are extracted

Explanation:

Partition coefficient (P) is defined as the ratio of solute dissolved in the organic solvent and the solute dissolved in the aqueous phase.

That is:

P = 7.5 = Concentration in dichloromethane / Concentration in water.

Knowing this, in the first extraction with 25mL of dichloromethane you will extract:

7.5 = (X/25mL) / (5g - X) / 100mL

Where X is the amount of compound A that is extracted.

7.5 = 100X / (125 - 25X)

937.5 - 187.5X = 100X

937.5 = 287.5X

3.26g of A are extracted in the first extraction.

In water will remain 5g - 3.26g = 1.74g

In the second extraction you will extract:

7.5 = (X/25mL) / (1.74g - X) / 100mL

7.5 = 100X / (43.5 - 25X)

326.25 - 187.5X = 100X

326.25 = 287.5X

1.13g are extracted in the second extraction.

And remain: 1.74g - 1.13g = 0.61g

In the third extraction you will extract:

7.5 = (X/25mL) / (0.61g - X) / 100mL

7.5 = 100X / (15.25 - 25X)

114.375 - 187.5X = 100X

114.375 = 287.5X

0.40g are extracted in the third extraction.

And remain: 0.61g - 0.40g = 0.21g

In the second extraction you will extract:

7.5 = (X/25mL) / (0.21g - X) / 100mL

7.5 = 100X / (5.25 - 25X)

39.375 - 187.5X = 100X

39.375 = 287.5X

0.14g are extracted in the fourth extraction.

Thus, after the three extractions you will extract: 0.14g + 0.40g + 1.13g + 3.26g = 4.93g are extracted

Final answer:

The process involves using the partitioncoefficient to determine how much of Compound A will prefer the dichloromethane solvent over the water. Following a calculation process through four rounds of extraction, it is concluded that approximately 4.999g of Compound A will be extracted using four 25mL portions of dichloromethane.

Explanation:

The partition coefficient of a compound is a measure of how much it prefers one solvent over another. Given that the partition coefficient of Compound A is 7.5 in dichloromethane with respect to water, we can predict how much of this compound could be extracted using four separate 25 mL portions of dichloromethane.

Here's the step-by-step calculation process:

We start with 5 grams of Compound A in 100 mL of water. Given the partition coefficient, in the initial phase, 5/(7.5+1)=0.625g remains in water and 7.5/8.5*5=4.375g goes into the dichloromethane.
After one extraction with 25ml of dichloromethane, the amount left in the water will be 0.625g*1/(7.5+1)=0.069g.
After the second extraction: 0.069g*1/(7.5+1) = 0.008g.
After the third extraction: 0.008g*1/(7.5+1) = 0.0009g.
After the fourth extraction: 0.0009g*1/(7.5+1) = 0.0001g.

In total, around 4.999g of compound A will be extracted using four 25mL portions of dichloromethane.

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When a polar bond is formed between 2 atoms which atom receives a partial positive charge

Answers

Answer:

The less electronegative atom

Explanation:

Water contains polar bonds. Water is made up of oxygen and hydrogen. Oxygen is more electronegative then hydrogen so it is partial negative (because electron spend more time around oxygen in the polar bond), whereas, hydrogen has a partial positive charge as it is less electronegative (electrons spend less time around hydrogen in this polar bond).

What may happen to the human body when exposed to an infectious agent? A. When infectious agents get into the human body, your body responds by functioning normally.

B. When infectious agents get into the human body, the body gets a surge of energy, causing a slight increase in body temperature, and you feel great.

C. When infectious agents get into the human body, your body responds by raising the core body temperature, causing a fever.

D.Nothing happens when the human body is exposed to an infectious agent.

Answers

Answer:

when infectious agents get into the human body your body responds by raising the core body temperature causing a fever

The answer is C it will raise your body temp and cause a fever

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