A student collected a sample of a gas in a 220 mL gas bulb until is pressure reached 0.757 atm at a temperature of 25.0 . The sample weighed 0.299g. What is the molAR mass of the gas?

43.84 g/mol

Explanation:

We use the ideal gas law to find the number of moles of gas present.

So PV = nRT where P = pressure of gass = 0.757 atm, V = volume of gas = 220 mL = 0.22 L, T = temperature of gas = 25 °C = 273 + 25 = 298 K and R = molar gas constant = 0.082 L atm mol⁻¹K⁻¹.

So, n = PV/RT = 0.757 atm × 0.22 L/(0.082 L atm mol⁻¹K⁻¹ × 298 K) = 0.16654 L atm/24.436  L atm mol⁻¹ = 0.00682 mol.

Since mass of gas m = 0.299 g

and n = m/M where M = molar mass of gas

So, M = m/n

\= 0.299 g/0.00682 mol

= 43.84 g/mol

So, the molar mass of the gas is 43.84 g/mol

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

so she was walking and she stepped on warm jeffy , uh uh uhh dadye i just pooped my pants