why do all of these elements- hydrogen, helium, lithium, and beryllium all have negative charges? explain
1 answer:
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Answer:
6.82g
0.59moles
Explanation:
1. What is the mass sample of 0.0500 moles of zinc chloride ?
Given parameters:
Number of moles ZnCl₂ = 0.05moles
Unknown:
Mass of the sample = ?
Solution:
To find the mass of a substance using the number of moles, it would be pertinent to understand what mole is.
A mole is a substance that contains the avogadro's number of particles.
It relates to the mass using the expression below;
Mass of a substance = number of moles x molar mass
Molar mass of ZnCl₂;
Atomic mass of Zn = 65.4g/mol
Cl = 35.5g/mol
Molar mass = 65.4 + 2(35.5) = 136.4g/mole
Mass of a substance = 0.05 x 136.4 = 6.82g
2. How many moles of potassium sulfide are in a 65.50g sample?
Given parameters:
Mass of K₂S = 65.5g
Unknown:
Number of moles = ?
Solution:
The number of moles of any substance is related to mass using the expression below;
Number of moles =
Molar mass of K₂S = 2(39) + 32 = 110g/mol
Number of moles = = 0.59moles
Explanation:
It is known that equation for ideal gas is as follows.
PV = nRT
The given data is as follows.
Pressure, P = 1500 psia, Temperature, T = = 104 + 460 = 564 R
Volume, V = 2.4 cubic ft, R = 10.73
Also, we know that number of moles is equal to mass divided by molar mass of the gas.
n =
m =
=
= 9.54 lb
Hence, molecular weight of the gas is 9.54 lb.
- We will calculate the density as follows.
d =
=
= 3.975
- Now, calculate the specific gravity of the gas as follows.
Specific gravity relative to air =
=
= 51.96