Hello!
Ok so for this problem we use the ideal gas law of PV=nRT and I take it that the scientist needs to store 0.400 moles of gas and not miles.
So if we have
n=0.400mol
V=0.200L
T= 23degC= 273k+23c=296k
R=ideal gas constant= 0.0821 L*atm/mol*k
So now we rearrange equation for pressure(P)
P=nRT/V
P=((0.400mol)*(0.0821 L*atm/mol*k)*(296k))/(0.200L) = 48.6 atm of pressure
Hope this helps you understand the concept and how to solve yourself in the future!! Any questions, please feel free to ask!! Thank you kindly!!!
Answer:
For finding frequency, we need to first find the period of the graph.
The period of a sinusoidal graph is the time interval in which it repeats its pattern.
In the graph, we can see, after
time, it repeats its pattern.
Hence the period of the graph is
.
Now we need to find its frequency 
The formula for frequency is 
This is the answer
i hope you pass the assignment
try your best!
You can use grease or oil