Hello this is my 3 attempt, please someone answer this i'm begging you. A sample of XH3(g) with a mass of 1.88 g occupies a volume of 550 mL at a pressure of 110 kPa and 28.5 oC. Identify element X. Justify your answer with calculations.

Your friend goes with you to the store and buys some hairspray. He looks at the can and asks: “why does it say: do not store in direct sunlight or heat?” Using your knowledge, explain to your friend why the can has this warning.

Explanation:

No worries, I got you :)

So for the first question, you need to use PV=nRT to find the n, or in other words, the number of moles. Then, you can find the molar mass since you know the grams and the moles

110 kPa / 101.3 = 1.085 atm (I converted it to atm so I can use the .08206 L atm/ k mol  for the rate)

550 ml / 1000 = .550 L (I converted mL to L in order to use the .08206 L atm/ k mol for the Rate)

28.5 c + 273 = 301.5 K (I converted C to K in order to use the .08206 L atm/ k mol for the Rate)

PV=nRT

(1.085) (.550 L) = n (0.08206) (301.5)

Divide the (0.08206) (301.5) to get n alone:

(1.085) (.550 L) / (0.08206) (301.5) = n

When I divided, I got n= .02412 moles, and since we have 1.88g , we divide the 1.88 by .02412 to get the molar mass (grams/mole)

77.94 g/mole is the molar mass

we know that there are 3 H's in the compound, so we do 3(1.008) and subtract 77.94 by what you get.

3 x 1.008 = 3.024 > 77.94-3.024 = 74.9

Now we look at the periodic table and try to find an element that has a molar mass of 74.9

Arsenic (As) has a molar mass of 74.922, which is close enough. Plus, Arsenic has a charge of 3, so it fits with the 3 hydrogens.