Answer:
pH = 1.32
Explanation:
H₂M + KOH ------------------------ HM⁻ + H₂O + K⁺
This problem involves a weak diprotic acid which we can solve by realizing they amount to buffer solutions. In the first deprotonation if all the acid is not consumed we will have an equilibrium of a wak acid and its weak conjugate base. Lets see:
So first calculate the moles reacted and produced:
n H₂M = 0.864 g/mol x 1 mol/ 116.072 g = 0.074 mol H₂M
54 mL x 1L / 1000 mL x 0. 0.276 moles/L = 0.015 mol KOH
it is clear that the maleic acid will not be completely consumed, hence treat it as an equilibrium problem of a buffer solution.
moles H₂M left = 0.074 - 0.015 = 0.059
moles HM⁻ produced = 0.015
Using the Henderson - Hasselbach equation to solve for pH:
ph = pKₐ + log ( HM⁻/ HA) = 1.92 + log ( 0.015 / 0.059) = 1.325
Notes: In the HH equation we used the moles of the species since the volume is the same and they will cancel out in the quotient.
For polyprotic acids the second or third deprotonation contribution to the pH when there is still unreacted acid ( Maleic in this case) unreacted.
The answer should be D hope this helps
Answer:
THE NEW VOLUME OF THE GAS IS 406 mL WHEN THE TEMPERATURE CHANGES FROM 765 K TO 315 K.
Explanation:
When the temperature changes from 765 K to 315K, the volume has changed from 986 mL to?
V1 = 986 mL = 0.986 L
T1 = 765 K
T2 = 315 K
V2 = unknown
Using Charles' equation of gas laws;
V1 / T1 = V2 / T2
Making V2 the subject of the formula:
V2 = V1 T2 / T1
V2 = 0.986 * 315 / 765
V2 = 0.406 L
V2 = 406 mL
So therefore, the volume of a gas changes from 986 mL to 406 mL as a result of a change in temperature from 765 K to 315 K.
Answer:
An educated guess based on what you already know.
Explanation:
