Volcano you make the volcano with baking soda and vinegera
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: 253.8
Explanation:
The molar mass of iodine is 126.904. Multiply that by two and you get approximately 253.8 grams in two moles.
The atomic mass can be defined as the mass of neutrons and protons in the atom. The atomic mass of the oxygen isotope is 18 amu.
<h3>What is an atom?</h3>
An atom is the smallest particle comprised of three subatomic units, namely electrons, protons, and neutrons.
The number of electrons in the atoms determines the atomic number, while the number of protons and neutrons determines the atomic mass.
The atomic mass can be given as:

The oxygen isotope has been comprised of 10 neutrons and 8 protons. The atomic mass of the isotope is given as:

The atomic mass of the oxygen isotope is 18 amu. Thus, option C is correct.
Learn more about atomic mass, here:
brainly.com/question/5566317
Always use least amount of sig figs possible. So this 9.7 would be (answer): 2 sig figs