Answer:

Explanation:
We can use the Ideal Gas Law — pV = nRT
Data:
V = 15.0 L
n = 0.55 mol
T = 300 K
Calculation:

Mass per volume percent is simply calculated by getting the ratio of the mass in g of solute and the volume in mL of the solution multiplied by 100 percent. In the problem, we are given all the required values. Calculation is as follows:
%w/v = 140 / 1590 x 100 = 8.81%
The drawing above is acting as a B) a screw.
Answer: Number of molecules of hydrogen gas 
Explanation:

Number of moles of sodium =
According to reaction , 2 moles of sodium produces 1 mole of hydrogen gas , then 2.11 mol of sodium will=
of hydrogen gas that is 1.05 moles of hydrogen gas.
Number of molecules =
moles of substance
Moles of hydrogen gas formed = 1.05 moles
Number of molecules of hydrogen gas =
moles of hydrogen gas
Number of molecules of hydrogen gas 
I think D, because water evaporates. Once it gets hot. Then condensation. I think