Question

Calculations First Trial UPDATED

Theoretical yield (CaCO3):

Actual yield (CaCO3):

Percent yield:

Moles of Ca present in original solution, based on actual yield:

Mass of CaCl2 present in original solution, based on actual yield:

Can someone please help me with these three easy questions please? Thank you! SHOW ALL WORK!!

THIS IS MY DATA FROM MY LAB EXPERIMENT. I JUST NEED FOR YOU TO FIND THE ANSWERS TO THE ABOVE QUESTIONS WITH WORK SHOWN!

Table 1: Data and Observations
	Mass
CaCl2 :	ORGINAL MASS: 2.0g AFTER 24 HOURS 5.8g
K2CO3 :	2.5g
Filter Paper	2.1 g
Watch Glass	33.6g
Precipitate	3.3g

Procedure

Put on your safety glasses and gloves (provided in your safety box).

Turn on the scale by pressing the button labeled "0/T". If your scale does not turn on, you may have to remove the battery cover and remove a small strip of plastic from the battery housing. Once the scale is on, press the "0/T" button a second time to zero the scale. Make sure that the units are in grams (g). If not, press the M button until the units displayed are in grams.

Place a weigh boat on the scale and record the mass in Table 2. Zero the mass of the weigh boat by pressing the "0/T" button. Your scale should now read 0 g.

Add 2.0 g of CaCl₂ to the weigh boat. Record the mass in Table 2. Set this sample aside, and let it sit exposed to the air (but otherwise undisturbed) for 24 hours. Complete Steps 3 - 23 while you wait.

Place a 250 mL beaker on the scale and zero it.

Add 2.0 g of CaCl₂ to the beaker. Record the exact mass of the powder in Table 1.

Remove the beaker from the scale. Use a 100 mL graduated cylinder to measure and pour 50 mL of distilled water into the beaker and mix with the stir rod until all the CaCl₂ has dissolved.
Note: This is an exothermic process, so the beaker may become warm.

Place a 50 mL beaker on the scale and zero the scale.

Add 2.5 g of K₂CO₃ to the 50 mL beaker. Record the exact mass of the powder in Table 1.

Remove the beaker from the scale. Use the 100 mL graduated cylinder to measure and pour 25 mL of distilled water into the 50 mL beaker. Mix with the stir rod until all the K₂CO₃ has dissolved.

Rinse the stir rod with water.

Add all of the K₂CO₃ solution to the beaker containing the CaCl₂ solution. It is important that all of the K₂CO₃ is added to the beaker. To ensure this, rinse the 50 mL beaker with up to 5 mL distilled water, and pour the rinse in the CaCl₂ solution.

Using the stopwatch to keep time, stir the solution with the stir rod for four minutes. Then, allow it to sit for 15 minutes. This will allow sufficient time for the chemical reaction to occur.

Rinse the stir rod with water.

Place a piece of filter paper on the scale and record the mass in Table 1.

Place a watch glass on the scale and record the mass in Table 1.

Fold the filter paper in half and in half again so that it resembles a triangle with one arched side.

Pull apart one fold of the filter paper so that three sides of the filter paper remain together, with one side making up the other half of the funnel shape (Figure 5).

Hold the funnel over a sink or any sized container. Place the paper into the funnel and use a pipette to drip 5 mL of distilled water around the edges of the filter paper. This will prevent the filter paper from rising up out of the funnel.

Rest the funnel on top of the Erlenmeyer flask.

After 15 minutes has passed, swirl the beaker and slowly filter the solution (that you created in Step 9) from the 250 mL beaker through the filter paper. Additional distilled water may also be used to transfer any remaining solid into the filtration apparatus.

After all the solution has been filtered, use the pipette to rinse the filter paper with approximately 5 mL of isopropyl alcohol to aid the drying process. Allow the isopropyl alcohol to completely drip through the filter before removing filter paper from the funnel.

Carefully remove the filter paper. Unfold and place it precipitate-side up onto the pre-weighed watch glass. Be sure not to lose any precipitate during this transfer.

Allow the precipitate to dry, undisturbed, for at least 24 hours. Determine the mass of the product recovered by re-weighing the system and subtracting the weight of the filter paper and watch glass. Record your data in Table 1.

Re-weigh the sample of CaCl₂ that was allowed to sit exposed for 24 hours. Subtract the mass of the weigh boat and record the mass and your observations in Table 2.

TABLE 2 IS NOT IMPORTANT IN SOLVING THE QUESTION AS IT JUST ASKS FOR MY OBERVATION OF CaCl₂ AFTER 24 HOURS. ALSO TO FIND THE ACTUAL YIELD, YOU WOULD HAVE TO FIND FIRST THE PERCENT YIELD AND THEORTICAL YIELD.

Answer 1

Solution :-

Balanced reaction equation

CaCl2 + K2CO3 --- > CaCO3(s) + 2KCl

Using the mass of each reactant we can find the amount of product it can form

Calculating the mass of product using the CaCl2 reactant mass

(5.8 g CaCl2 * 1 mol /110.98 )*(1mol CaCO3 /1 mol CaCl2)*(100.09 g/ 1 mol CaCO3)= 5.23 g CaCO3

Calculating the mass of product using the K2CO3 reactant mass

(2.5 g K2CO3 * 1 mol / 138.21 g)*(1 mol CaCO3 / 1mol K2CO3)*(100.09 g / 1 mol CaCO3) = 1.81 g CaCO3

Since the K2CO3 gives the less amount of the product therefore the K2CO3 is limiting reactant

Therefore theoretical yield is 1.81 g CaCO3

Actual yield CaCO3= precipitate – filter paper

                                  = 3.3 g – 2.1 g

                                = 1.2 g

Percent yield = [actual yield / theoretical yield]*100%

                        = [1.2g / 1.81 g]*100%

                       = 66.3 %

Moles of Ca present in the original solution based on actual yield

(1.2 g CaCO3 * 1 mol / 100.09 g)*(1 mol Ca / 1 mol CaCO3) = 0.012 mol Ca

Mass of CaCl2 in the original solution based on actual yield

(0.012 mol Ca * 1 molCaCl2 / 1 mol Ca)*(110.98 g / 1 mol CaCl2) = 1.33 g CaCl2