I think the answer is:
B. Chemical Change.
Answer:
- <em>(B.) The pH of a buffer solution is determined by the ratio of the concentration of conjugate base to the concentration of strong acid.</em>
- <em>(C.) A buffer is generally made up of a weak acid and its conjugate base. </em>
- <em>(D.) The pH of a buffer solution does not change significantly when any amount of a strong acid is added.</em>
Explanation:
A buffer is solution which resists change in pH upon addition of either acids or bases.
The pH of a buffer is calculated by the ratio of the concentration of base to concentration of acid. The weak acid and conjugate base have a Ka similar to the pH desired.
Answer:
A larger nuclear charge :)
Explanation:
Coffee is acidic so the first one would be correct
a. mol O₂=0.5
b. volume O₂ = 25 cm³
c. i. the total volume of the two reactants = 75 cm³
c. ii. the volume of nitrogen dioxide formed = 50 cm³
<h3>Further explanation</h3>
Reaction
2NO(gas) + O₂(gas) ⇒ 2NO₂ (gas)
a.
mol NO = 1
From the equation, mol ratio NO : O₂ = 2 : 1, so mol O₂ :

b.
From Avogadro's hypothesis, at the same temperature and pressure, the ratio of gas volume will be equal to the ratio of gas moles
Because mol ratio NO : O₂ = 2 : 1, so volume O₂ :

c.
i. total volume of reactants : 25 cm³+ 50 cm³=75 cm³
ii. the volume of nitrogen dioxide formed :
mol ratio NO : NO₂ = 2 : 2, so volume NO₂ = volume NO = 50 cm³