What was the purpose of letting the transformed cells sit in LB for a few minutes before spreading them onto the plates?

Calculate the pH of a solution prepared by mixing: (Show your work for these calculations) pk of acetic acid is 4.75 a. two mole

kupik [55]

Answer:

Explanation:

To calculate pH you need to use Henderson-Hasselbalch formula:

pH = pka + log₁₀ $\frac{[A^-]}{[HA]}$

Where HA is the acid concentration and A⁻ is the conjugate base concentration.

The equilibrium of acetic acid is:

CH₃COOH ⇄ CH₃COO⁻ + H⁺ pka: 4,75

Where CH₃COOH is the acid and CH₃COO⁻ is the conjugate base.

Thus, Henderson-Hasselbalch formula for acetic acid equilibrium is:

pH = 4,75 + log₁₀ $\frac{[CH_{3}COO^-]}{[CH_{3}COOH]}$

a) The pH is:

pH = 4,75 + log₁₀ $\frac{[2 mol]}{[2 mol]}$

pH = 4,75

b) The pH is:

pH = 4,75 + log₁₀ $\frac{[2 mol]}{[1mol]}$

pH = 5,05

I hope it helps!

7 0

4 years ago

SOVA2 [1]

This problem is providing us with the recommended maintenance dose of penicillin for children as 1.0 mg/kg/hr by injection. Thus, the delivery rate for a 40-pound child is required, if 10 mL of a 25 mg/mL solution of penicillin is added to a 100-mL bottle of saline. At the end, the result is 8.0 mL/hr:

<h3>Dimensional analysis:</h3>

In chemistry, dimensional analysis allows us to obtain a specific result given relevant information about it. Although a formula is not always provided, one can use the units as a reference for the calculations.

For example, this problem asks for the rate, in mL/hr, at which a child gets this dose, so the first step will be to get the mass of the child in kilograms:

$40 lb*\frac{0.4536kg}{1lb}= 18.144kg$