Adding hot cocoa to hot water would be a chemical change
Answer:
4.07
Explanation:
There is some info missing. I think this is the original question.
<em>A solution is prepared at 25 °C that is initially 0.057 M in nitrous acid (HNO₂), a weak acid with Ka = 4.5 × 10⁻⁴, and 0.30 M in sodium nitrite (NaNO₂). Calculate the pH of the solution. Round your answer to 2 decimal places.</em>
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Nitrous acid is a weak acid and nitrite (coming from sodium nitrite) is its conjugate base. Together, the form a buffer system. We can calculate its pH using the Henderson-Hasselbach equation.
pH = pKa + log [base]/[acid]
pH = -log 4.5 × 10⁻⁴ + log 0.30/0.057
pH = 4.07
Answer:
pH = 12.20
Explanation:
Ca(OH)2 is a strong base, so it dissociates completely. A 0.08 M solution of Ca(OH)2 is 0.16 M OH-, since every mole of Ca(OH)2 has 2 OH-.
Calculate pOH using [OH-] = 0.16 M
pOH = -log(0.16) = 0.80
pH = 14 - pOH = 14 - 0.80 = 12.20
Answer:
A. since Nitrogen has 7 electrons and when it gains 3 electrons it will have 10 electrons. using short hand rule it is [Ne]