Answer:
your answer is 30f
Explanation:
The coldest possible temperature, or absolute zero, is -273.15 degrees Celsius, or 0 degrees Kelvin. So, 10 degrees Celsius (and this shouldn't be taken too literally) is in fact only about 1.8 per cent warmer than 5 degrees, and 30 degrees is only about 5.2 per cent warmer than 15 degrees.
<span>No, I believe this is not an example of a chemical reaction.
What we actually see here is a physical change of the solution. Since we are adding
more water to an aqueous solution which is also made up mostly of water, what
we are simply basically doing is dilution. Since the solution is being diluted,
so definitely the color turned lighter.</span>
Answer:-
Solution:- As is clear from the given Ka value, Cinnamic acid is a weak acid. let's calculate the moles of acid and KOH added to it from their given molarities and mL.
For KOH, 
= 0.002 mol
For Cinnamic acid, 
= 0.003 mol
Acid and base react as:

The reaction takes place in 1:1 mol ratio. Since the moles of acid are in excess, the acid is still remaining when all the kOH is used.
0.002 moles of KOH react with 0.002 moles of Cinnamic acid to form 0.002 moles of potassium cinnamate. Excess moles of Cinnamic acid = 0.003 - 0.002 = 0.001
As the solution have weak acid and it's salt(or we could say conjugate base), it is a buffer solution and the pH of the buffer solution could easily be calculated using Handerson equation:

pKa could be caluted from given Ka value using the formula:
pKa = - log Ka

pKa = 4.44
let's plug in the values in Handerson equation and calculate the pH:

pH = 4.44+0.30
pH = 4.74
So, the first choice is correct, pH is 4.74.
Answer:
False
Explanation:
It will actually speed it up