Answer :
This is an ideal gas law question. It uses the ideal gas law equation, PV =nRT.
P = pressure, V = volume, n = moles, R is the constant, and T is temperature in kelvin. The temperature needs to be converted Kevin first. To convert from Celsius to Kevin, you add 273, meaning that the temp in Kevin is 403K. Then plug all the info into the equation to solve for moles.
(1.00atm)(1.280L)=n(0.0821)(403K)
n = 0.0387moles
To find molar mass, divide mass by moles.
4.03g / 0.0387moles = 104.17g/mol
104g/mol rounded to three significant digits
P = pressure, V = volume, n = moles, R is the constant, and T is temperature in kelvin. The temperature needs to be converted Kevin first. To convert from Celsius to Kevin, you add 273, meaning that the temp in Kevin is 403K. Then plug all the info into the equation to solve for moles.
(1.00atm)(1.280L)=n(0.0821)(403K)
n = 0.0387moles
To find molar mass, divide mass by moles.
4.03g / 0.0387moles = 104.17g/mol
104g/mol rounded to three significant digits