First, we determine the moles of Mg(NO₃)₂ present:
moles = mass / Mr
= 46.5 / (24 + 2 x (14 + 16 x 3))
= 0.4 mole
Each mole of Mg(NO₃)₂ contains 2 moles of Nitrogen atoms.
Moles Nitrogen = 0.4 x 2
= 0.8 mole
These atoms are isotopes, they have the same number of protons which means the atoms are of the same ELEMENT, but they have different numbers of neutrons.
Answer:
56.9 mmoles of acetate are required in this buffer
Explanation:
To solve this, we can think in the Henderson Hasselbach equation:
pH = pKa + log ([CH₃COO⁻] / [CH₃COOH])
To make the buffer we know:
CH₃COOH + H₂O ⇄ CH₃COO⁻ + H₃O⁺ Ka
We know that Ka from acetic acid is: 1.8×10⁻⁵
pKa = - log Ka
pKa = 4.74
We replace data:
5.5 = 4.74 + log ([acetate] / 10 mmol)
5.5 - 4.74 = log ([acetate] / 10 mmol)
0.755 = log ([acetate] / 10 mmol)
10⁰'⁷⁵⁵ = ([acetate] / 10 mmol)
5.69 = ([acetate] / 10 mmol)
5.69 . 10 = [acetate] → 56.9 mmoles
Answer:
H2
Explanation:
H (or hydrogen), being a halogen, as an atom, has 7 valence electrons. This means that it naturally bonds with another atom of the same isotope in order to reach the desired total of valence electrons: 8.
So... H+H = H2. EZ
