Answer:
The correct answer is option 2 (6 liters of N2)
Explanation:
The complete question
Which sample of gas at STP has the same number of molecules as 6 liters of Cl2(g) at STP?
(1) 3 liters of O2(g)
(2) 6 liters of N2(g)
(3) 3 moles of O2(g)
(4) 6 moles of N2(g)
Step 1: Data given
Volume = 6 L
STP = 1 atm and 273 K
Step 2: Calculate moles of Cl2
p*V = n*R*T
n = (p*V)/ (R*T)
⇒with n = the number of moles Cl2 = TO BE DETERMINED
⇒with V = the volume of Cl2 = 6.0 L
⇒with p = the pressure of Cl2 = 1 atm
⇒with R = the gas constant = 0.08206 L*atm/mol*K
⇒ with T = the temperature = 273 K
n = (1.0 * 6.0 ) (0.08206 * 273)
n = 0.2678 moles Cl2
This means we need 0.2678 moles of a gas at STP
Option 3 has 3 moles of O2 ⇒ Not the same number of molecules
Option 4 has 6 moles of N2 ⇒ Not the same number of molecules
For 3 liters of O2 we'll have:
⇒with n = the number of moles O2 = TO BE DETERMINED
⇒with V = the volume of O2 = 3.0 L
⇒with p = the pressure of O2 = 1 atm
⇒with R = the gas constant = 0.08206 L*atm/mol*K
⇒ with T = the temperature = 273 K
n = (1.0 * 3.0 ) (0.08206 * 273)
n = 0,1339 moles ⇒ Not the same number of molecules
For 6 liters of N2 we'll have
⇒with n = the number of moles N2 = TO BE DETERMINED
⇒with V = the volume of N2 = 6.0 L
⇒with p = the pressure of N2 = 1 atm
⇒with R = the gas constant = 0.08206 L*atm/mol*K
⇒ with T = the temperature = 273 K
n = (1.0 * 6.0 ) (0.08206 * 273)
n = 0.2678 moles N2 ⇒ The same number of molecules
The correct answer is option 2 (6 liters of N2)
