Explanation:
As it is known that molarity is the number of moles present in a liter of solution.
Mathematically, Molarity = 
As it is given that molarity is 0.10 M and volume is 10.0 ml. As 1 ml equals 0.001 L. Therefore, 10.0 ml will also be equal to 0.01 L.
Hence, putting these values into the above formula as follows.
Molarity =
0.10 M = 
no. of moles = 0.001 mol
As molar mass of KCN is equal to 65.12 g/mol. Therefore, calculate the mass of KCN as follows.
No. of moles = 
0.001 mol = 
mass = 0.06152 g
Thus, we can conclude that 0.06152 grams of KCN are in 10.0 ml of a 0.10 M solution.
Answer:
The mass percent of carbon in C₁₄H₁₉NO₂ is 72.1%.
Explanation:
To calculate the mass percent of carbon in C₁₄H₁₉NO₂ we have to follow two simple steps:
1st) Look for the atomic weight of each element in the Periodic Table and then multiply each one by its subscript in the molecule and finally sum all of them to find the molar weight of the molecule:
Carbon atomic weight . Carbon subscript = 12 . 14 = 168g
Hydrogen atomic weight . Hydrogen subscript = 1 . 19 = 19g
Nitrogen atomic weight . Nitrogen subscript = 14 . 1 = 14g
Oxygen atomic weight . Oxygen subscript = 16 . 2 = 32g
The molar weight of C₁₄H₁₉NO₂ is: 168g + 19g + 14g +32g = 233g.
2nd) Find the mass percent of carbon with a Rule of three:
If 233g represents the 100% of mass, the 168g of carbon in the molecule will represents the 72.1% of mass.
The Rule of three is:
233g ------------- 100%
168g ------------- = (168 . 100)/233 = 72.1% mass of carbon.
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longitudinal waves is the answer hope this helps
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