The displacement, d, in millimeters of a tuning fork as a function of time, t, in seconds can be modeled with the equation d = 0
2 answers:
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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
Answer: The percent yield is, 93.4%
Explanation:
First we have to calculate the moles of Na.
Now we have to calculate the moles of
The balanced chemical reaction is,
As, 1 mole of bromine react with = 2 moles of Sodium
So, 0.189 moles of bromine react with = moles of Sodium
Thus bromine is the limiting reagent as it limits the formation of product and Na is the excess reagent.
As, 1 mole of bromine give = 2 moles of Sodium bromide
So, 0.189 moles of bromine give = moles of Sodium bromide
Now we have to calculate the percent yield of reaction
Therefore, the percent yield is, 93.4%