Number 1: (A.)
Number 2: (A.)
Number 3: (B.)
I'm probably wrong but that is what i think
<u>Answer:</u> The pressure that must be applied to the apparatus is 0.239 atm
<u>Explanation:</u>
To calculate the osmotic pressure, we use the equation for osmotic pressure, which is:

or,

where,
= osmotic pressure of the solution
i = Van't hoff factor = 1 (for non-electrolytes)
= mass of sucrose = 3.40 g
= molar mass of sucrose = 342.3 g/mol
= Volume of solution = 1 L
R = Gas constant = 
T = temperature of the solution = ![20^oC=[20+273]K=293K](https://tex.z-dn.net/?f=20%5EoC%3D%5B20%2B273%5DK%3D293K)
Putting values in above equation, we get:

Hence, the pressure that must be applied to the apparatus is 0.239 atm
Answer is True. They can in one lifetime by either humans or natural
Answer: The empirical formula of the compound is 
Explanation:
Empirical formula is defined formula which is simplest integer ratio of number of atoms of different elements present in the compound.
Percentage of iron in a compound = 36.76 %
Percentage of sulfur in a compound = 21.11 %
Percentage of oxygen in a compound = 42.13 %
Consider in 100 g of the compound:
Mass of iron in 100 g of compound = 36.76 g
Mass of iron in 100 g of compound = 21.11 g
Mass of iron in 100 g of compound = 42.13 g
Now calculate the number of moles each element:
Moles of iron=
Moles of sulfur=
Moles of oxygen=
Divide the moles of each element by the smallest number of moles to calculated the ratio of the elements to each other
For Iron element = 
For sulfur element =
For oxygen element = 
So, the empirical formula of the compound is 