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

Question

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 of gaseous arsine?
In sig fig 4
Thanks!

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Thiên Ân 5 months 2021-08-24T04:57:18+00:00 1 Answers 40 views 0

Answers ( )

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    2021-08-24T04:58:20+00:00

    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.

    PV = nRT\\1 atm \times 0.372 L = n \times 0.0821 L atm/mol K \times 273.15 K\\n = 0.0165 mol

    2). As number of moles are also equal to mass of a substance divided by its molar mass.

    So, number of moles of Arsine (AsH_{3}) (molar mass = 77.95 g/mol) is as follows.

    No. of moles = \frac{mass}{molar mass}\\0.0165 mol = \frac{mass}{77.95 g/mol}\\mass = 1.286 g

    Density is the mass of substance divided by its volume. Hence, density of arsine is calculated as follows.

    Density = \frac{mass}{volume}\\= \frac{1.286 g}{0.372 L}\\= 3.45 g/L

    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.

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