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## PLZ HELP *NO LINKS* 1) How many moles of gaseous arsine (AsH3) occupy 0.372 L at STP? In sig fig 4 2) What is the density

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## Answers ( )

Answer: (1). There are 0.0165 moles of gaseous arsine (AsH3) occupy 0.372 L at STP.(2). The density of gaseous arsine is 3.45 g/L.Explanation:1).At STP the pressure is 1 atm and temperature is 273.15 K. So,using the ideal gas equation number of moles are calculated as follows.PV = nRT

where,

P = pressure

V = volume

n = number of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.2).As number of moles are also equal to mass of a substance divided by its molar mass.So,

number of moles of Arsine(molar mass = 77.95 g/mol) is as follows.Density is the mass of substance divided by its volume. Hence, density of arsine is calculated as follows.

Thus, we can conclude that

0.0165 moles of gaseous arsine (AsH3) occupy 0.372 L at STP and the density of gaseous arsine is 3.45 g/L.