Answer:
3.38 moles of O2.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
4CH2OH + 5O2 → 4CO2 + 6H2O
From the balanced equation above,
4 moles of CH2OH required 5 moles of O2 for complete combustion.
Finally, we shall determine the number of mole of O2 needed to react with 2.7 moles of CH2OH. This can be obtained as follow:
From the balanced equation above,
4 moles of CH2OH required 5 moles of O2 for complete combustion.
Therefore, 2.7 moles of CH2OH will require = (2.7 × 5)/4 = 3.38 moles of O2 for complete combustion.
Thus, 3.38 moles of O2 is required.
Answer:
pH = 12.61
Explanation:
First of all, we determine, the milimoles of base:
0.120 M = mmoles / 300 mL
mmoles = 300 mL . 0120 M = 36 mmoles
Now, we determine the milimoles of acid:
0.200 M = mmoles / 100 mL
mmoles = 100 mL . 0.200M = 20 mmoles
This is the neutralization:
HCOOH + OH⁻ ⇄ HCOO⁻ + H₂O
20 mmol 36 mmol 20 mmol
16 mmol
We have an excess of OH⁻, the ones from the NaOH and the ones that formed the salt NaHCOO, because this salt has this hydrolisis:
NaHCOO → Na⁺ + HCOO⁻
HCOO⁻ + H₂O ⇄ HCOOH + OH⁻ Kb → Kw / Ka = 5.55×10⁻¹¹
These contribution of OH⁻ to the solution is insignificant because the Kb is very small
So: [OH⁻] = 16 mmol / 400 mL → 0.04 M
- log [OH⁻] = pOH → 1.39
pH = 14 - pOH → 12.61
Answer: the percentage of acetic acid will be low.
Explanation: The major aim during titration of acids and bases is to determine the endpoint , that is exact point where the acid in the beaker changes colour, (in this case, pink )with an additional drop from the burette containing the base, since it is usually difficult to mark the equivalence point that tells us when all the substrate in the beaker has been neutralized completely with the buretted substance.
Overshooting the end point is an error which can occur when the person involved in the the titration accidently goes beyond this endpoint by adding too much of the substance(base) from the burette into the beaker missing the exact endpoint.
This implies that the person has added too much of the burreted liquid, ie the base than required , making the acid in the beaker to continue to react resulting to a lower concentration of the acid (acetic acid) with excess base.(NaOH)
Answer:
<h2>
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Explanation:
According to hooks law "provide the elastic limit of an elastic material is not exceeded the extension e is directly proportional to the applied force F"
where F= applied force
k= spring constant
e= extension
Given data
length of string l = 16cm
extension e = 20-16= 4cm
applied force = 5N
we need t o first calculate the spring constant k
apply the formula
we can now calculate the extension of the string when supporting a 6N weight
The length of the string when supporting a 6N weight is
<em>COMMENT </em><em>:According to the analysis an extra weight of 1N will cause add 0.8cm to the length of the string</em>
