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2.67 grams of butane (C4H10) is combusted in a bomb calorimeter. The temperature increases from 25.68 C to 36.2C. What is the change in the internal energy (deltaE) in KJ/mol for the reaction if the heat capacity of the bomb calorimeter is 5.73 kJ/C?

Answers

Answer 1

Answer:

The internal energy : 1310.43 kJ/mol

Further explanation

Internal energy (ΔE) can be formulated for Calorimeter :

$\tt \Delta E=C*.\Delta t$

C= the heat capacity of the calorimeter

Δt=36.2-25.68=10.52°C

$\tt \Delta E=5.73 kJ/^oC* 10.52^oC=60.2796~kJ$

mol butane(MW=58,12 g/mol)

$\tt (2.67)/(58,12 )=0.046$

the internal energy (ΔE) in KJ/mol

$\tt (60.2796)/(0.046)=1310.43~kJ/mol$

Answer 2

Answer:

Final answer:

The change in internal energy when 2.67 grams of butane is combusted in a bomb calorimeter, given a temperature increase from 25.68 C to 36.2C and a heat capacity of 5.73 kJ/C for the calorimeter, is approximately 1308 kJ/mol.

Explanation:

To solve the problem of calculating the changes in internal energy when 2.67 grams of butane (C4H10) is combusted in a bomb calorimeter, it is necessary to understand calorimeter's heat capacity and how a bomb calorimeter works.

The first step will be to calculate the change in temperature which here is the final temperature subtracted from the initial temperature: 36.2 C - 25.68 C = 10.52 C.

Then, we multiply this temperature change by the heat capacity of the calorimeter to find the total heat produced by the reaction in kJ: 10.52 C * 5.73 kJ/C = 60.18 kJ.

The final step is to convert grams of butane to moles, because we are asked to find the energy change in kJ/mol. The molar mass of butane (C4H10) is approximately 58.12 g/mol. So we have approximately 2.67 g / 58.12 g/mol = 0.046 mol.

Finally, we divide the heat produced by the number of moles to get the energy change per mole of butane: 60.18 kJ / 0.046 mol = approximately 1308 kJ/mol.

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Which of the following best describes the crest of a transverse wave?а. length
b. high point
c. speed
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Answers

Answer:

Explanation:

Calculate the mass in grams for 0.251 moles of Na2CO3

Answers

Answer:

Explanation:

the molar mass for Na2CO3 is 2*23+12+3*16=106 g/mole

106*0.251=26.606 grames

Is my answer right? How many millilitres of 1.33 mol L−1 H2SO4(aq) are required to completely neutralize 49.3 mL of 0.830 mol L−1 KOH(aq) ?

I got 15.4 once and now I got 61.4? Are they correct? if so, which one?

Answers

Final answer:

To neutralize the KOH solution, we need 61.4 mL of 1.33 mol L−1 H2SO4(aq).

Explanation:

To find the volume of the H2SO4 solution needed to neutralize the KOH solution, we can use the equation:

Mole of H2SO4 = Molarity of KOH x Volume of KOH

First, calculate the moles of KOH:
Moles of KOH = Molarity of KOH x Volume of KOH = 0.830 mol/L x (49.3 mL / 1000 mL) = 0.04089 mol

Since H2SO4 is a diprotic acid and KOH is a strong base, the reaction will be:
H2SO4 + 2 KOH -> K2SO4 + 2 H2O

Therefore, the ratio between the moles of H2SO4 and KOH is 1:2. This means that twice the moles of KOH will be needed to neutralize the H2SO4. Calculate the moles of H2SO4 needed:
Moles of H2SO4 needed = 2 x Moles of KOH

= 2 x 0.04089 mol

= 0.08178 mol

Finally, calculate the volume of the H2SO4 solution needed:
Volume of H2SO4 = Moles of H2SO4 / Molarity of H2SO4 = 0.08178 mol / 1.33 mol/L

= 0.0614 L

= 61.4 mL

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The following data is given to you about a reaction you are studying: Overall reaction: 2A  D Proposed mechanism: Step 1 A + B  C (slow) Step 2 C + A  D + B (fast) [A]o = 0.500 M [B]o = 0.0500 M [C]o = 0.500 M [D]o = 1.50 M This reaction was run at a series of temperatures and it was found that a plot of ln(k) vs 1/T (K) gives a straight line with a slope of -982.7 and a Y intercept of -0.0726. What is the initial rate of the reaction at 298K?

Answers

Answer : The initial rate of the reaction at 298 K is, $8.6* 10^(-4)M/s$

Explanation :

The Arrhenius equation is written as:

$K=A* e^{(-Ea)/(RT)}$

Taking logarithm on both the sides, we get:

$\ln k=-(Ea)/(RT)+\ln A$ ............(1)

where,

k = rate constant

Ea = activation energy

T = temperature

R = gas constant = 8.314 J/K.mole

A = pre-exponential factor

The equation (1) is of the form of, y = mx + c i.e, the equation of a straight line.

Thus, if we plot a graph of $\ln k$ vs $(1)/(T)$ then the graph shows a straight line with negative slope. That means,

Slope of the line = $-(Ea)/(R)$

And,

Intercept = $\ln A$

As we are given that:

Slope of the line = -982.7 = $-(Ea)/(R)$

Intercept = -0.0726 = $\ln A$

Now we have to calculate the value of rate constant by putting the value of slope, intercept and temperature (298K) in equation 1, we get:

$\ln k=-(982.7)/(298)+(-0.0726)$

$\ln k=-3.37$

$k=0.0344s^(-1)$

The value of rate constant is, $0.0344s^(-1)$

Now we have to calculate the initial rate of the reaction at 298 K.

As we know that the slow step is the rate determining step. So,

The slow step reaction is,

$A+B\rightarrow C$

The expression of rate law for this reaction will be,

$Rate=k[A][B]$

As we are given that:

[A] = 0.500 M

[B] = 0.0500 M

k = $0.0344s^(-1)$

Now put all the given values in the rate law expression, we get:

$Rate=(0.0344)* (0.500)* (0.0500)$

$Rate= 8.6* 10^(-4)M/s$

Therefore, the initial rate of the reaction at 298 K is, $8.6* 10^(-4)M/s$

For the experiments from 1-3 with the same temperature change, what other parameters are the same at the initial reaction conditions?a. mmol HCl total mL solution
b. mmol NaOH Initial concentration of NaOH
c. mL H2O Initial concentration of HCl

Answers

Answer:

The following parameters:

total mL solution
mmol NaOH
initial concentration of NaOH

Explanation:

The options have been incorrectly arranged in the question statement given here. The three conditions mentioned above are what would be observed to remain the same when this experiment is carried out.

Calculate the molar solubility of Cd(OH)2 when buffered at a pH = 12.30. The Ksp for Cd(OH)2 is 2.5 x 10-14. Calculate the molar solubility of Cd(OH)2 when buffered at a pH = 12.30. The Ksp for Cd(OH)2 is a.2.5 x 10-14 M.
b. 8.5 x 10-6 M
c. 6.3 x 10-11 M
d. 1.3 x 10-12 M
e. 5.0 x 10-2 M
f. 1.8 x 10-5 M

Answers

Answer:

c. 6,3x10⁻¹¹M

Explanation:

The solubility of a buffer is defined as the concentration of the dissolved solid in a saturated solution. For the Cd(OH)₂, solubility is:

[Cd²⁺] = S

The dissolution of Cd(OH)₂ is:

Cd(OH)₂ ⇄ Cd²⁺ + 2OH⁻

And the ksp is defined as:

ksp = [Cd²⁺][OH⁻]²

As ksp = 2,5x10⁻¹⁴ and [OH⁻] at pH=12,30 = 10^-(14-12,30) = 0,01995M

2,5x10⁻¹⁴ = [Cd²⁺]×(0,01995M)²

[Cd²⁺] = 6,3x10⁻¹¹M

That means solubility is c. 6,3x10⁻¹¹M

I hope it helps!

Final answer:

The molar solubility of Cd(OH)2 when buffered at a pH of 12.30 can be calculated using the concept of hydrolysis. The correct answer is 6.3 x 10^(-11) M.

Explanation:

To calculate the molar solubility of Cd(OH)2 when buffered at a pH of 12.30, we need to use the concept of hydrolysis. Cd(OH)2 is a slightly soluble salt that undergoes hydrolysis in aqueous solution. At a high pH value, OH- ions react with water to form more OH- ions, shifting the equilibrium towards the hydrolysis reaction.

First, we write the balanced equation for the hydrolysis reaction: Cd(OH)2(s) ⇌ Cd2+(aq) + 2OH-(aq)
Since OH- is being produced, we can assume that the concentration of OH- is much greater than that of Cd2+. Therefore, we can ignore the concentration of Cd2+ when calculating the solubility product (Ksp).
Next, we use the equation for the hydrolysis reaction to write the expression for the solubility product constant (Ksp): Ksp = [Cd2+][OH-]^2
The concentration of OH- ions in a basic solution is related to the pH by the equation: pOH = 14 - pH
Using this equation, we can calculate the pOH of the buffered solution: pOH = 14 - 12.30 = 1.70
Then, we convert the pOH back to OH- concentration: [OH-] = 10^(-pOH) = 10^(-1.70)
Finally, we substitute the calculated [OH-] into the expression for Ksp to solve for the molar solubility of Cd(OH)2: [Cd(OH)2] = sqrt(Ksp / [OH-]^2)

After performing the calculations, the molar solubility of Cd(OH)2 when buffered at a pH of 12.30 is approximately 6.3 x 10^(-11) M. Therefore, the correct answer is option c. 6.3 x 10^(-11) M.

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