Answer:
rate of recrystallization = 4.99 × 10⁻³ min⁻¹
Explanation:
For Avrami equation:
To calculate the value of k which is a dependent variable for the above equation ; we have:
The time needed for 50% transformation can be determined as follows:
![y = 1-e ^{(-kt^n)} \\ \\ e^{(-kt^n)} = 1-y\\ \\ -kt^n = In(1-y) \\ \\ t =[ \dfrac{-In(1-y)}{k}]^{^{1/n}}](https://tex.z-dn.net/?f=y%20%3D%201-e%20%5E%7B%28-kt%5En%29%7D%20%5C%5C%20%5C%5C%20e%5E%7B%28-kt%5En%29%7D%20%3D%201-y%5C%5C%20%5C%5C%20-kt%5En%20%3D%20In%281-y%29%20%5C%5C%20%5C%5C%20t%20%3D%5B%20%5Cdfrac%7B-In%281-y%29%7D%7Bk%7D%5D%5E%7B%5E%7B1%2Fn%7D%7D)
![t_{0.5} =[ \dfrac{-In(1-0.4)}{9.030 \times 10^{-7}}]^{^{1/2.5}}](https://tex.z-dn.net/?f=t_%7B0.5%7D%20%3D%5B%20%5Cdfrac%7B-In%281-0.4%29%7D%7B9.030%20%5Ctimes%2010%5E%7B-7%7D%7D%5D%5E%7B%5E%7B1%2F2.5%7D%7D)
= 200.00183 min
The rate of reaction for Avrami equation is:
rate = 0.00499 / min
rate of recrystallization = 4.99 × 10⁻³ min⁻¹
Answer:
Agriculture was practiced for thousands of years without the use of artificial chemicals. Artificial fertilizers were first created during the mid-19th century. These new agricultural techniques, while beneficial in the short term, had an Institute of Plant Industry to improve traditional farming methods in India.
Explanation:
Answer:
ΔH for formation of 197g Fe⁰ = 1.503 x 10³ Kj => Answer choice 'B'
Explanation:
Given Fe₂O₃(s) + 2Al⁰(s) => Al₂O₃(s) + 2Fe⁰(s) + 852Kj
197g Fe⁰ = (197g/55.85g/mol) = 3.527 mol Fe⁰(s)
From balanced standard equation 2 moles Fe⁰(s) => 852Kj, then ...
3.527 mole yield (a higher mole value) => (3.527/2) x 852Kj = 1,503Kj (a higher enthalpy value).
______
NOTE => If 2 moles Fe gives 852Kj (exo) as specified in equation, then a <u>higher energy value</u> would result if the moles of Fe⁰(s) is <u>higher than 2 moles</u>. The ratio of 3.638/2 will increase the listed equation heat value to a larger number because 197g Fe⁰(s) contains more than 2 moles of Fe⁰(s) => 3.527 mole Fe(s) in 197g. Had the problem asked for the heat loss from <u>less than two moles Fe⁰(s)</u> - say 100g Fe⁰(s) (=1.79mole Fe⁰(s)) - then one would use the fractional ratio (1.79/2) to reduce the enthalpy value less than 852Kj.
I think this the the list of choices relating to the above question.
reaction rate
<span>activation energy </span>
<span>collision theory </span>
<span>spontaneous reaction
</span>
The term that best relate to ben's observation is REACTION RATE.
Reaction rate is defined as the speed at which the chemical reaction proceeds. It either is the amount of concentration of a product in a given unit of time or the concentration of the reactant that is being consumed in a unit of time.
