When 13.6 grams of kcl are dissolved in enough water to create a 180-gram solution, what is the solution's concentration, expres
2 answers:
Answer: 7.6% KCl
Explanation: Mass of solute is given as 13.6 grams and the mass of solution is 180 grams. The question asks to calculate the solution concentration, expressed as a percent by mass.
The formula for percent by mass is:
% by mass =
Let's plug in the values in the formula and do the calculations.
% by mass = = 7.6%
So, the correct choice is C) 7.6% KCl.
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<u>Answer:</u>
<u>For a:</u> The mass of acetic anhydride needed is 73.91 grams.
<u>For b:</u> The theoretical yield of aspirin is 130.43 grams.
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
.....(1)
- <u>For a:</u>
Given mass of salicylic acid =
Molar mass of salicylic acid = 138.121 g/mol
Putting values in equation 1, we get:
For the given chemical reaction:
By stoichiometry of the reaction:
1 mole of salicylic acid reacts with 1 mole of acetic anhydride.
So, 0.724 moles of salicylic acid will react with = of acetic anhydride.
Now, to calculate the mass of acetic anhydride, we use equation 1:
Moles of acetic anhydride = 0.724 moles
Molar mass of acetic anhydride = 102.09 g/mol
Putting values in equation 1, we get:
Hence, the mass of acetic anhydride needed is 73.91 grams.
- <u>For b:</u>
By stoichiometry of the reaction:
1 mole of salicylic acid is producing 1 mole of aspirin.
So, 0.724 moles of salicylic acid will produce = of aspirin.
Now, to calculate the mass of aspirin, we use equation 1:
Moles of aspirin = 0.724 moles
Molar mass of aspirin = 180.158 g/mol
Putting values in equation 1, we get:
Hence, the theoretical yield of aspirin is 130.43 grams.
42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.
<h3>What is a graduated cylinder?</h3>A tall narrow container with a volume scale is used especially for measuring liquids.
The graduated cylinder contains water
mL is a volume unit.
Water volume = 50.6 ml
The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.
The new volume is the lead ball volume plus the original water volume :
Final volume = Vlead ball+ Water original volume
Hence, 42.4 ml is the volume in milliliters of the lead ball.
Learn more about the graduated cylinder here:
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