Answer: Option (4) is the correct answer.
Explanation:
A mixture is defined as a substance that contains two or more different substance that are physically mixed with each other.
If solute particles are evenly distributed in a solvent then it is known as a homogeneous mixture.
For example, salt dissolved in water is a homogeneous mixture.
If solute particles are unevenly distributed into the solvent then it is known as a heterogeneous mixture.
For example, sand in water is a heterogeneous mixture.
Thus, we can conclude that the statement a mixture must contain at least two different substances, is correct about mixtures.
Answer:
A) t = 22.5 min and B) t = 29.94 min
Explanation:
Initial concentration, [A]₀ = 100
Final concentration = 100 -75 = 25
Time = 45 min
A) First order reaction
ln[A] − ln[A]₀ = −kt
Solving for k;
ln[25] − ln[100] = - 45k
-1.386 = -45k
k = 0.0308 min-1
How long after its start will the reaction be 50% complete?
Initial concentration, [A]₀ = 100
Final concentration, [A] = 100 -50 = 50
Time = ?
ln[A] − ln[A]₀ = −kt
Solving for k;
ln[50] − ln[100] = - 0.0308 * t
-0.693 = -0.0308 * t
t = 22.5 min
B) Zero Order
[A] = [A]₀ − kt
Using the values from the initial reaction and solving for k, we have;
25 = 100 - k(45)
-75 = -45k
k = 1.67 M min-1
How long after its start will the reaction be 50% complete?
Initial concentration, [A]₀ = 100
Final concentration, [A] = 100 -50 = 50
Time = ?
[A] = [A]₀ − kt
50 = 100 - (1.67)t
-50 = - 1.67t
t = 29.94 min
As mentioned, this is a trial-and-error process. I typed in the Avogadro's number 6.022×10²³ then added the largest number I could think of. Since infinity can be thought of as 99999...(and so on), I thought that the number should all be composed of 9. As I add 9 after one another, I ended with about 10 quadrillion before the display changed to 6.022000001×10²³. Therefore, the largest number is: 9,999,999,999,999,999.
