Can anyone just show me the steps and point me in the right direction???

A sample of oxygen gas has a volume of 8.00 L at 20.0 ° C and 700. torr. How many moles does the sample contain?

Use PV=nRT

4.5L

Of course! To determine the number of moles in a sample of a gas, you can use the ideal gas law equation:

PV = nRT

Where:
P = pressure of the gas (in atm)
V = volume of the gas (in L)
n = number of moles of the gas
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature of the gas (in Kelvin)

In this case, we have the volume (8.00 L) and the pressure (700. torr), but the temperature is given in Celsius. To convert Celsius to Kelvin, you need to add 273.15 to the Celsius temperature.

So let's convert 20.0 °C to Kelvin:

T = 20.0 °C + 273.15 = 293.15 K

Now we have all the values we need. Plugging in the values into the ideal gas law equation, we have:

(700. torr) * (8.00 L) = n * (0.0821 L.atm/mol.K) * (293.15 K)

Simplifying the equation, we get:

n = (700. torr * 8.00 L) / (0.0821 L.atm/mol.K * 293.15 K)

Now, divide the left side of the equation by the right side to solve for n:

n = (700. torr * 8.00 L) / (0.0821 L.atm/mol.K * 293.15 K)

Calculating this expression will give you the number of moles in the sample.