Answer:
pH = 4.25
Explanation:
A solution composed of a weak acid and its conjugate base is a <em>buffer solution</em>. To calculate the pH of a buffer solution we use the Henderson-Hasselbach equation:
pH = pKa + log ([conjugate base]/[weak acid]
In this case, we have the following data:
[conjugate base] = [sodium benzoate] = 0.230 M
[weak acid] = [benzoic acid] = 0.205 M
The pKa of benzoic acid is 4.2. So, we introduce the data in the equation:
pH = 4.2 + log (0.230 M/0.205 M) = 4.2 + 0.050 = 4.25
A small sample of methane burns, releasing 120.0 kJ of heat and doing 830.0 kJ of work. The total energy released is -950.0 kJ.
Energy is a property that is transferred to a physical system, recognizable in the performance of work and in the form of heat and light.
A small sample of methane undergoes combustion. As the hot gas mixture expands, it releases energy (E).
- It releases 120.0 kJ of heat. By convention, when heat is released, we assign it a negative sign. Thus, q = -120.0 kJ.
- It does 830.0 kJ of work. By convention, when the system does work on the surroundings, we assign it a negative sign. Thus, w = -830.0 kJ.
The change in the energy is the sum of the heat released and the work done.
ΔE = q + w = -120.0 kJ + (-830.0 kJ) = -950.0 kJ
A small sample of methane burns, releasing 120.0 kJ of heat and doing 830.0 kJ of work. The total energy released is -950.0 kJ.
Learn more about energy here: brainly.com/question/13881533
Answer:
The radius of the centrifuge.
Explanation:
Hello,
Since the radius of the centrifuge is just a design parameter, it wouldn't be a cause of failure because it is used to know how many tubes could be fitted in into the centrifuge. On the other hand, keeping you attention away from other factors could turn into a failure as long as the sample could be poured down or just turn out inadequate for the expected results.
Best regards.
Answer:
0.0295M
Explanation:
As you can see, in the mixture you have KSCN and other compounds. The KSCN in solution is dissolved in K⁺ ions and SCN⁻ ions. That means initial concentration of SCN⁻ ions is the same of KSCN, 0.0800M.
You are adding 35.0mL of this solution and the total volume of the mixture is 20.0mL + 35.0mL + 40.0mL = 95.0mL.
That means you are diluting your solution 95.0mL / 35.0mL = 2.714 times.
And the concentration of SCN⁻ is:
0.0800M / 2.714 =
<h3>0.0295M </h3>
Answer:
HCl conc.= 6.0mol/L
Explanation:
From the dissociation of HCl= 1 mole H+ and 1mol Cl-, which is equivalent stoichiometrically in concentration to that of 1 mol HCl,
