The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.
To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.
From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.
1) From pV = nRT, n = pV / RT
Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K
n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol
mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042
=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol
Now from a periodic table or a table you get that the molar mass of He is 4g/mol
So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.
Answer:
54.99% yield
Explanation:
percent yield is just the amount you obtained over the amount expected times 100%.
(experimental value/theoretical value) x 100%
= (107.9 g/196.2 g) x 100%
=54.99% yield
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Since nickles atomicnumber is 28, that means it has 28 protons, which are positively charged. To cancel out the positive charge and make it nuetral, there isalso 28 electrons which are negatively charged.
Nickel has 31 neutrons because an atoms mass is the number of protons + neutrons. The # of protons is 28. The mass # is 59. So, there are 31 neutrons.
