Answer: 94.07%
Explanation:
Percentage yield can be calculated by the formula
%yield = Experimental yield/Theoretical yield x100
Experimental yield = 7.93g
Theoretical yield = 8.43
%yield = Experimental yield/Theoretical yield x100
%yield = 7.93/8.43 x 100 = 94.07%
It will approximately take 2 hours and 50 minutes
Answer : The order of potential energy from least to greatest is,
(3) < (1) < (4) < (2)
Explanation :
Formula used :

where,
P.E = potential energy
m = mass of an object
g = gravity constant = 
h = height
Now we have to calculate the potential energy of following options.
(1) Tiles a 15-kilogram stone found at a height of 3 meters.

(2) 10 kilograms of water stored at a height of 9 meters.

(3) 1-kilogram ball located 20 meters.

(4) In the area box of books weighing 25 kilograms placed on a shelf 2 meters high.

From this we conclude that, the order of potential energy from least to greatest is,
(3) < (1) < (4) < (2)
Answer:
the answer is 1:3:2
Hope this helps, let me know if you need any other help, Stoichiometry is hard