The mass number is the sum of the protons and neutrons
64 = #protons + #neutrons
Find the number of protons given the number of neutrons
64 = #protons + 33
#protons = 31
In a neutral element (such as this), the number of electrons equals the number of protons
#electrons = #protons
#electrons = 31
A. the number dots shown on the lewis dot diagrams for the element in the period
Answer: The vapor pressure of methanol solution at 298K is 107.12 torr
Explanation:
As the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.
The formula for relative lowering of vapor pressure will be,
where,
= relative lowering in vapor pressure
i = Van'T Hoff factor = 1 (for non electrolytes)
= mole fraction of solute =
Given : 38.5 g of urea is present in 142 g of methanol
moles of solute (urea) =
moles of solvent (methanol) =
Total moles = moles of solute + moles of solvent = 0.64 + 4.4 = 5.04
= mole fraction of solute =
Thus the vapor pressure of methanol solution at 298K is 107.12 torr
For #1, we can show conservation of mass stoichiometrically converting the starting amount of reactants into the final amount of products
For instance 2H2O2 —> 2H2O + O2
If we start with 70g H2O2,
our theoretical yield of H2O~ 37g
Our theoretical yield of O2~ 33g
So 70g = 37g + 33g
For #2, an Acid-base reaction always forms a salt and water. For instance,
HCl + NaOH —> H2O + NaCl
This is called neutralization and I would think that Chemical properties would be different, as well as the physical properties.
Using the
V1/T1=V2/T2
where
T1=50C= 323.15K
T2= -5C=268.15 K
V2= 212m^3
substitute the given values, we will get the initial volume
V1=V2T1/T2
V1= 255.48m^3
The initial volume is 255.48m^3