Answer:
pH = 5.54
Explanation:
The pH of a buffer solution is given by the <em>Henderson-Hasselbach (H-H) equation</em>:
- pH = pKa + log
![\frac{[CH_3COO^-]}{[CH_3COOH]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BCH_3COO%5E-%5D%7D%7B%5BCH_3COOH%5D%7D)
For acetic acid, pKa = 4.75.
We <u>calculate the original number of moles for acetic acid and acetate</u>, using the <em>given concentrations and volume</em>:
- CH₃COO⁻ ⇒ 0.377 M * 0.250 L = 0.0942 mol CH₃COO⁻
- CH₃COOH ⇒ 0.345 M * 0.250 L = 0.0862 mol CH₃COOH
The number of CH₃COO⁻ moles will increase with the added moles of KOH while the number of CH₃COOH moles will decrease by the same amount.
Now we use the H-H equation to <u>calculate the new pH</u>, by using the <em>new concentrations</em>:
- pH = 4.75 + log
= 5.54
Answer:
- <u>You need to convert the number of atoms of Ca into mass in grams, using Avogadro's number and the atomic mass of Ca.</u>
Explanation:
The amount of matter is measured in grams. Thus, you need to convert the number of atoms of Ca (calcium) into mass to compare with 2.45 grams of Mg.
To convert the atoms of calcium into mass, you divide by Avogadro's number, to obtain the number of moles of atoms, and then divide by the atomic mass of calcium.
<u />
<u>1. Number of moles, n</u>
<u />
<u>2. Mass</u>
- mass = number of moles × atomic mass
- mass = 0.053969mol × 40.078g/mol = 2.16g
Then, 2.45 g of Mg represent a greaer mass than the 3.25 × 10²² atoms of Ca.
Answer:
i think that it is an atmosphere.
Explanation:
In order to determine the number of protons in 20.02 mol of Ne, we use Avogadro's number to convert the number of moles to number of atoms, 1 mol = 6.022 x 10^23 atoms. From there, we must know the number of protons in a Neon atom, which is 10. Thus, the formula will be:
(20.02 mol Ne)x(6.022 x 10^23 atoms/mol)x(10 protons/1 atom Ne) =
1.2056 x 10^26 protons
No. (Just have to max out 20 characters.)
