Answer:- Third choice is correct, 17.6 moles
Solution:- The given balanced equation is:

We are asked to calculate the moles of potassium hydroxide needed to completely react with 2.94 moles of aluminium sulfate.
From the balanced equation, there is 1:6 mol ratio between aluminium sulfate and potassium hydroxide.
It is a simple mole to mole conversion problem. We solve it using dimensional set up as:

= 17.6 mol KOH
So, Third choice is correct, 17.6 moles of potassium hydroxide are required to react with 2.94 moles of aluminium sulfate.
Answer : Average atomic weight of copper atoms will be
63.62 u.
Explanation : For calculating average atomic weight for any given atom we use this formula,
m = Σ

X % abundance
where, m - avg atomic mass of isotope.
and

- mass of isotope
on solving we get,
m = [63 u X (69/100)] + [65 u X (31/100)] = 63.62 u.
What this is??????????????????
Answer: The balloons volume would increase.
Explanation: This is because when the balloon enters a warmer climate it expands due to more freedom within the molecules movement.