A 0.528 gram sample of a metal, M, reacts completely with sulfuric acid according to: M+H2SO4 -> MSO4+H2
A volume of 205 mL of hydrogen is collected over water; the water level in the collecting vessel is the same as the outside level. Atmospheric pressure is 756.0 Torr and the temperature is 25°C. Calculate the atomic mass of the metal.
? g/mol
Is the answer 3.24x10^-3 g/mol?
No. If you will show your work I will look for the error. I think I answered this for you yesterday. I used as pressure of Ptotal = 756 mm + pH2O
and a table gave 23.8 mm for vapor pressure of H2O at 25C.
n=.0833 mols
molar mass=(.0833mols/.528g)=.158g/mol
What did you substitute for PV = nRT?
P=.995atm
V=.205L
n=?
R=.0821 Lxatm/molxk)
T=298K
It is 65.4g/mol
I would use P = (756-23.8)/760 = 0.963 atm; however, going with your number will still get close to the right answer.
PV = nRT or
n = PV/RT = 0.995*0.205/0.8206*298
n = 0.00834. You had to use some other (incorrect) version of n = PV/RT.
Then n = grams/molar mass or
molar mass = grams/n
molar mass = 0.528.0.00834 = ?
If you use P = (756-23.8)/760 I think you will get 65.4 which is Zn.
To solve this problem, we need to determine the number of moles of hydrogen gas produced and use that information to find the molar mass of the metal.
First, let's figure out the number of moles of hydrogen gas produced using the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant (0.0821 L·atm/(mol·K)), and T is the temperature in Kelvin.
The given values are:
Volume (V) = 205 mL = 0.205 L
Pressure (P) = 756.0 Torr
We need to convert the pressure to atm by dividing it by 760 Torr (since 1 atm = 760 Torr):
Pressure (P) = 756.0 Torr / 760 Torr/atm = 0.9947 atm
The temperature needs to be converted from Celsius to Kelvin by adding 273.15:
Temperature (T) = 25°C + 273.15 = 298.15 K
Now we can use the ideal gas law equation to find the number of moles (n):
(0.9947 atm) x (0.205 L) = n x (0.0821 L·atm/(mol·K)) x (298.15 K)
n = (0.9947 atm x 0.205 L) / (0.0821 L·atm/(mol·K) x 298.15 K) ≈ 0.008 moles
Next, we need to determine the molar mass of the metal. We know that 0.528 grams of the metal reacts completely, producing 0.008 moles of hydrogen gas. To find the atomic mass of the metal, we'll divide the mass by the number of moles:
Molar mass = Mass of the metal (g) / Number of moles
Molar mass = 0.528 g / 0.008 mol ≈ 66 grams/mol
Therefore, the atomic mass of the metal (M) is approximately 66 g/mol.
The answer is not 3.24x10^-3 g/mol, it is approximately 66 g/mol.