8). How many moles of oxygen gas must be placed in a 35.0 L container in order to exert a pressure of 2.80 atmospheres at 15.0°C?

4.1 moles

Explanation:

Applying

PV = nRT equation 1

Where P = pressure, V = volume, n = number of moles, R = molar gas constant, T = Temperature.

make n the subject  of the equation

n = PV/RT Equation 2

From the question,

Given: V = 35 L , P = 2.8 atm, T = 15 °C  = (15+273) = 288 K, R = 0.083 L.atm/K.mol

Substitute these values into equation 2

n = (35×2.8)/(0.083×288)

n = 4.1 moles

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

c, liquids evaporate, creating a gas