Trace evidence can end up transferring to the crime scene through Locard's Exchange Principle, which states that whenever two things come into contact with one another, there is an exchange of physical material A.K.A evidence. This exchange is most often done through physical contact, such as a struggle or a suspect attempting to hide evidence or alter the crime scene. It can even involve a suspect's shirt sleeve brushing against some wet paint.
I hope I helped!
Answer :
The time taken by the reaction is 19.2 seconds.
The order of reaction is, second order reaction.
Explanation :
The general formula to determine the unit of rate constant is:
Unit of rate constant Order of reaction
0
1
2
As the unit of rate constant is 
. So, the order of reaction is second order.
The expression used for second order kinetics is:
![kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}](https://tex.z-dn.net/?f=kt%3D%5Cfrac%7B1%7D%7B%5BA_t%5D%7D-%5Cfrac%7B1%7D%7B%5BA_o%5D%7D)
where,
k = rate constant = 
t = time = ?
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
= final concentration = 0.97 M
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial concentration = 2.48 M
Now put all the given values in the above expression, we get:
Therefore, the time taken by the reaction is 19.2 seconds.
Answer:
Copper is element number 29
4th row
11th column
Answer:
84.24 g
Explanation:
Given data:
Mass of oxygen = 75 g
Mass of Al required to react = ?
Solution:
Chemical equation:
4Al + 3O₂ → 2Al₂O₃
Number of moles of oxygen:
Number of moles = mass/ molar mass
Number of moles = 75 g/ 32 g/mol
Number of moles = 2.34 mol
Now we will compare the moles of oxygen with Al.
O₂ : Al
3 : 4
2.34 : 4/3×2.34 = 3.12 mol
Mass of Al required:
Mass = number of moles × molar mass
Mass = 3.12 mol × 27 g/mol
Mass = 84.24 g
