They are found in group 3 of the periodic table.
Answer:
Explanation:
Method 1 proportion
1 mole of chromium is 52 grams
11.9 moles = x grams
1/11.9 = 52/x Cross multiply
x = 11.9 * 52
x = 618.8 grams
Now I have used an approximate mass for Chromium. The answer you get here is expected to reflect the weigth given on your periodic table Use that to get your answer. You should give a number very close to mine. Round to 3 places as in 619.
Method Two Formula
mols = given mass / molecular mass
11.9 = given mass / 51.9961 Multiply both sides by 51.9961
11.9 *51.9961 = given mass
given mass = 618.75
given mass = 619
Answer:
Yes, there will be liquid present and the mass is 5.19 g
Explanation:
In order to do this, we need to use the equation of an ideal gas which is:
<em>PV = nRT (1)</em>
<em>Where:</em>
<em>P: Pressure</em>
<em>V: Volume</em>
<em>n: number of moles</em>
<em>R: gas constant</em>
<em>T: Temperature</em>
we know that the pressure is 856 Torr at 300 K. So, if we want to know if there'll be any liquid present, we need to calculate the moles and mass of the CCl3F at this pressure and temperature, and then, compare it to the initial mass of 11.5 g.
From (1), solving for moles we have:
<em>n = PV/RT (2)</em>
Solving for n:
P = 856/760 = 1.13 atm
R = 0.082 L atm / mol K
n = 1.13 * 1 / 0.082 * 300
n = 0.0459 moles
Now, the mass is:
m = n * MM (3)
The molar mass of CCl3F reported is 137.37 g/mol so:
m = 0.0459 * 137.37
m = 6.31 g
Finally, this means that if we put 11.5 g of CCl3F in a container, only 6.31 g will become gaseous, so, this means it will be liquid present, and the mass is:
m = 11.5 - 6.31
m = 5.19 g
The main difference between gas pressure and vapour pressure is that gas pressure is exerted by the gases above the surface of a substance whereas vapour pressure is exerted by liquids above the surface of a substance