Answer:
After the transfer the pressure inside the 20 L vessel is 0.6 atm.
Explanation:
Considering O2 as an ideal gas, it is at an initial state (1) with V1 = 3L and P1 = 4 atm. And a final state (2) with V2 = 20L. The temperature remain constant at all the process, thus here applies the Boyle-Mariotte law. This law establishes that at a constant temperature an ideal gas the relationship between pressure and volume remain constant at all time:

Therefore, for this problem the step by step explanation is:

Clearing P2 and replacing

Cu + S ---> CuS
by reaction 1 mol 1 mol
from the problem 0.25 mol 0.25 mol
0.25 mol Cu
A triple beam balance is used to measure mass
Answer:- 3.12 g carbon tetrachloride are needed.
Solution:- The balanced equation is:

From given actual yield and percent yield we will calculate the theoretical yield that would be further used to calculate the grams of carbon tetrachloride.
percent yield formula is:
percent yield = 


theoretical = 3.44 g
From balanced equation, there is 2:1 mol ratio between dichloethane and carbon tetrachloride.
Molar mass of dichloroethane is 84.93 gram per mol and molar mass of carbon tetrachloride is 153.82 gram per mol.

= 
So, 3.12 grams of carbon tetrachloride are needed to be reacted.
Answer:
357.475
Explanation:
First you need periodic table and you have to look for mass
Fe = 3 x 55.845 = 167.535
P = 2 x 30.97 = 61.94
o = 4 x 2 so 8 oxygen = 8 x 16 = 128
add all and you get 357.475