How many moles of oxygen will occupy a volume of 2.50 at 1.20 atm and 25.0 c?

The number of mol of oxygen is 0, 123

Explanation:

We use the formula PV=nRT. We convert the temperature in Celsius into Kelvin. 0°C=273 K---> 25°C=273+25= 298K

PV=nRT---> n=(PV)/(RT)

n= (1,20 atm x2,50 L)/(0,082 l atm/  K mol  x 298K)

n=0,122769684 mol

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.