A gas has a volume of 1400 milliliters at a temperature of 20 K and a pressure of 1.0 atm. What will be the new volume when the temperature is changed to 40 K and the pressure is changed to 0.50 atm?​

5.6 L or 5600 mL

Explanation:

This question asks for the use of combined gas law:

(P1)(V1) / (T1) = (P2)(V2) / (T2)

...where pressure (P) is in atm, volume (V) is in liters, and temperature (T) is in kelvin.

1400 ml is 1.4 L, and everything else is already in the right units.

(1 atm)(1.4 L) / (20 K) = (0.5 atm)(V2) / (40 K)

Just solve the equation for V2, and you get a new volume of 5.6 liters.

(1)(1.4) / (20) = (.5x) / (40)

1.4 / 20 = .5x / 40

2.8 = .5x

x = 5.6

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%