Use both the ideal gas law and the van der Waals equation to calculate the pressure in atmospheres of 45.0 g of NH3 gas in a 1.000-L container at 0 °C, 50 °C, and 100 °C. For NH3, a = 4.17 L² atm/mol² and b = 0.0371 L/mol.

The Ideal Gas Law is a fundamental equation in chemistry that relates the pressure, volume, temperature, and number of moles of a gas. It is expressed as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin. This law assumes that gas particles do not interact and occupy no volume, making it a good approximation under many conditions.

The Van der Waals equation is an adjustment of the Ideal Gas Law that accounts for the volume occupied by gas molecules and the attractive forces between them. It is expressed as (P + a(n/V)²)(V - nb) = nRT, where 'a' and 'b' are constants specific to each gas. This equation provides a more accurate description of real gas behavior, especially at high pressures and low temperatures, where deviations from ideality occur.

To solve gas law problems, it is essential to calculate the number of moles of a substance using its mass and molar mass. For ammonia (NH3), the molar mass is approximately 17.03 g/mol. By dividing the mass of the gas (45.0 g) by its molar mass, one can determine the number of moles, which is necessary for applying both the Ideal Gas Law and the Van der Waals equation to find the pressure in the container.