By definition, a biological diversity is commonly defined as the term in which all species of living organisms are living in a specific region, provided they are beneficial to one another and the food chain is balanced. In addition to that, the correct definition of the term among the choices provided would be letter B.
Answer is: molarity is 0,155 M.
V(solution) = 90,0 mL = 0,09 L.
ω(NaCl) = 0,92% ÷ 100% = 0,0092.
d(solution) = 1 g/mL.
m(solution) = V(solution) · d(solution).
m(solution) = 90 mL · 1 g/mL = 90 g.
m(NaCl) = 90 g · 0,0092 = 0,828 g.
n(NaCl) = 0,828 g ÷ 58,4 g/mol.
n(NaCl) = 0,014 mol.
c(solution) = 0,014 mol ÷ 0,09 L.
c(solution) = 0,155 mol/L.
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
Hey there!
This is not reversible.
We know that this is a chemical change because heat is released (it burned brightly) and it formed a new substance (white powder).
Chemical changes are usually not reversible.
Since this is a chemical change, then this is not reversible.
Hope this helps!
