Answer:
To keep a record of who has the evidence and when
Explanation:
Don't want anyone tampering with it, hope this helps!!!
Answer:It creates a heat source on the cold water and the molecules act against each other and then it becomes steam.
Explanation:I had to take this on a test.
Answer:
<h2>Hereis the correct answer </h2>
(A.-9)
Explanation:
<h3>STUDY CORRECTION. </h3>
Answer:
1.Physical. People measure water by themselves.
2.Physical. People chop wood.
Explanation:
(this is all I can answer for you. you have to explain it by yourself tho.)
I dont know if I'm correct so you should double check.
Answer:
the pH of HCOOH solution is 2.33
Explanation:
The ionization equation for the given acid is written as:

Let's say the initial concentration of the acid is c and the change in concentration x.
Then, equilibrium concentration of acid = (c-x)
and the equilibrium concentration for each of the product would be x
Equilibrium expression for the above equation would be:
![\Ka= \frac{[H^+][HCOO^-]}{[HCOOH]}](https://tex.z-dn.net/?f=%5CKa%3D%20%5Cfrac%7B%5BH%5E%2B%5D%5BHCOO%5E-%5D%7D%7B%5BHCOOH%5D%7D)

From given info, equilibrium concentration of the acid is 0.12
So, (c-x) = 0.12
hence,

Let's solve this for x. Multiply both sides by 0.12

taking square root to both sides:

Now, we have got the concentration of ![[H^+] .](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%20.)
![[H^+] = 0.00465 M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%20%3D%200.00465%20M)
We know that, ![pH=-log[H^+]](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E%2B%5D)
pH = -log(0.00465)
pH = 2.33
Hence, the pH of HCOOH solution is 2.33.