Theoretical Yield, Molar Mass, and Percent Yield

In summary, the conversation involved three questions about calculating the molar mass of calcium chloride dihydrate, the theoretical yield of calcium carbonate, and the percent yield of calcium carbonate. The first question required using the periodic table values to calculate the molar mass, while the second question involved using stoichiometry to determine the theoretical yield. The third question required calculating the percent yield using the actual and theoretical yields.
  • #1
chmdummy1982
2
0
Hi, I have a few questions that I am struggling with. Any help would be greatly appreciated.

Question 1
Calculate the molar mass of calcium chloride dihydrate, CaCl2 • 2H2O.
Please use the Periodic Table values rounded to the hundredths place for your calculation and round your answer to the hundredths place and remember, the "dot" (•) means closely associated, reprsenting the ADDITION of two waters of hydration to the calcium chloride formula unit.

Question 2
What is the theoretical yield of calcium carbonate if 2.97 grams of calcium chloride dihydrate reacts with excess sodium carbonate according to the balanced chemical reaction shown below?

Please use molar mass values calculated and rounded to the hundredths place, and round your answer to the hundredths place.

Question 3
What is the percent yield of calcium carbonate if your theoretical yield was 2.07 grams, and your actual yield was 1.46 grams, from the balanced chemical reaction shown below?
Please round your answer to the tenths place.
CaCl2•2H20(aq)+Na2CO3(aq)->CaCO3(aq)+2NaCL(aq)+2H20(I)
 
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  • #2
1) Simply use the molar masses provided by the periodic table to calculate the molar mass. So you'd take 40.00g (Ca) +2(35.45g Cl) + 4(1.01g H) + 2(16.00g) to find your molar mass.

2) Divide 2.97 g by the molar mass of CaCl2•2H20(aq) you got in 1). Using stoichiometry, CaCl2•2H20(aq) to CaCO3(aq) is a 1:1 ratio, which means your theoretical yield would be whatever answer you got from 2.97g/Molar Mass of CaCl2•2H20(aq).

3) Percent Yield = ( Actual Yield / Theoretical Yield ) x 100%
 
  • #3


Question 1: The molar mass of calcium chloride dihydrate, CaCl2 • 2H2O, can be calculated by adding the molar masses of each element present in the compound. The molar mass of CaCl2 is 110.98 g/mol (40.08 g/mol for Ca and 2 x 35.45 g/mol for Cl), and the molar mass of 2H2O is 36.04 g/mol (2 x 2 x 1.01 g/mol for H and 2 x 16.00 g/mol for O). Adding these two values together gives a molar mass of 147.02 g/mol for CaCl2 • 2H2O.

Question 2: The theoretical yield of calcium carbonate can be calculated using the given mass of calcium chloride dihydrate and the balanced chemical equation. First, convert the given mass of calcium chloride dihydrate to moles by dividing by its molar mass (147.02 g/mol). This gives 0.0202 moles of CaCl2 • 2H2O. According to the balanced equation, 1 mole of CaCl2 • 2H2O will produce 1 mole of CaCO3. Therefore, the theoretical yield of CaCO3 is also 0.0202 moles. To convert this to grams, multiply by the molar mass of CaCO3 (100.09 g/mol). The theoretical yield of CaCO3 is 2.01 grams.

Question 3: The percent yield of a reaction is calculated by dividing the actual yield by the theoretical yield and multiplying by 100%. In this case, the actual yield is 1.46 grams and the theoretical yield is 2.01 grams. Dividing 1.46 by 2.01 and multiplying by 100% gives a percent yield of 72.6%. This means that only 72.6% of the expected amount of CaCO3 was actually produced in the reaction. Possible reasons for a lower than expected yield could include incomplete reaction, loss of product during transfer, or experimental error.
 

1. What is theoretical yield?

Theoretical yield is the maximum amount of product that can be produced in a chemical reaction based on the amount of reactants used and assuming 100% efficiency.

2. How is molar mass calculated?

Molar mass is calculated by adding up the atomic masses of all the atoms in a molecule. This can be found on the periodic table of elements.

3. What is percent yield?

Percent yield is the ratio of the actual yield (the amount of product obtained in a chemical reaction) to the theoretical yield, expressed as a percentage. It is a measure of the efficiency of a reaction.

4. How is percent yield calculated?

Percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100%. The formula is: (actual yield ÷ theoretical yield) x 100%.

5. What are some factors that can affect percent yield?

Some factors that can affect percent yield include impurities in the reactants, side reactions that produce unwanted products, and incomplete reactions due to factors like temperature, pressure, and concentration.

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