Given, half life of a certain radioactive element = 800 years.
Amount of substance remaining at time t = 12.5%
Lets consider the initial amount of the radioactive substance = 100%
Using the half life equation:
A = A₀(1/2)^t/t₁/₂
where A₀ is the amount of radioactive substance at time zero and A is the amount of radioactive substance at time t, and t₁/₂ is the half-life of the radioactive substance.
Plugging the given data into the half life equation we have,
12.5 = 100 . (1/2)^t/800
12.5/100 = (1/2)^t/800
0.125 = (0.5)^t/800
(0.5)^3 = (0.5)^t/800
3 = t/800
t = 2400 years
Thus the object is 2400 years old.
Answer:
in both nucleophil attach the c and leaving group leave but in acyl nu. subsituation c of carbonyl because of double bond with o have bigger positive charge and is better electrophil so do it faster,also alkyl nu. subsituation can have rearangment if going from sn1 and in sn2 sterichemistry of molecule change , acyl nu. subsituation most of time is better
Answer:
Explanation:
Given parameters:
Molarity of KOH = 0.26M
Volume of H₂SO₄ = 19.76mL
Molarity of H₂SO₄ = 0.20M
Unknown:
Volume of KOH = ?
Solution:
This is a neutralization reaction in which an acid reacts with a base to produce salt and water:
H₂SO₄ + 2KOH → K₂SO₄ + 2H₂O
We solve from the known to the unknown in the reaction.
The known is the acid and from there we can find the number of moles of the acid to be completely neutralized:
Number of moles of acid = molarity x volume
Number of moles of acid = 19.76 x 0.20 = 3.95mol
From the balanced reaction equation:
1 mole of acid reacts with 2 moles of the bases KOH
3.95mole of acid would react with 3.95moles x 2 of the base
Number of moles of reacting base = 7.90moles
To find the volume of base;
Volume of base = 
Volume =
= 30.40mL
Learn more:
Neutralization brainly.com/question/6447527
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2O2 IS THE OXIDIZING AGENT BECAUSE IT GIVES ALL OTHER ELEMENT OXYGEN