The first thing you do before performing anything in the laboratory is to read the procedure and prepare the materials needed. Next, if you already have the solution where you are supposed to take your 20 mL sample, then have it near you. Then, prepare a volumetric flask (750 mL) and a 20-mL pipette. Wash the pipette 3 times with the sample solution. If your diluent is water, wash the flask 3 times with water. Now, get 20 mL of sample from your parent solution, then add it to the flask (previously washed with water). Finally, add water until the mark in the flask and make sure that the water added is up to the mark based on the lower meniscus reading to be accurate in the amount inside the flask. <span />
The thermal decomposition of calcium carbonate will produce 14 g of calcium oxide. The stoichiometric ratio of calcium carbonate to calcium oxide is 1:1, therefore the number of moles of calcium carbonate decomposed is equal to the number of moles of calcium oxide formed.
Further Explanation:
To solve this problem, follow the steps below:
- Write the balanced chemical equation for the given reaction.
- Convert the mass of calcium carbonate into moles.
- Determine the number of moles of calcium oxide formed by using the stoichiometric ratio for calcium oxide and calcium carbonate based on the coefficient of the chemical equation.
- Convert the number of moles of calcium oxide into mass.
Solving the given problem using the steps above:
STEP 1: The balanced chemical equation for the given reaction is:
![CaCO_{3} \rightarrow \ CaO \ + \ CO_{2}](https://tex.z-dn.net/?f=CaCO_%7B3%7D%20%5Crightarrow%20%5C%20CaO%20%5C%20%2B%20%5C%20CO_%7B2%7D)
STEP 2: Convert the mass of calcium carbonate into moles using the molar mass of calcium carbonate.
![mol \ CaCO_{3} \ = 25 \ g \ CaCO_{3} \ (\frac{1 \ mol \ CaCO_{3}}{100.0869 \ g \ CaCO_{3}})\\ \\\boxed {mol \ CaCO_{3} \ = 0.2498 \ mol}](https://tex.z-dn.net/?f=mol%20%5C%20CaCO_%7B3%7D%20%5C%20%3D%2025%20%5C%20g%20%5C%20CaCO_%7B3%7D%20%5C%20%28%5Cfrac%7B1%20%5C%20mol%20%5C%20CaCO_%7B3%7D%7D%7B100.0869%20%5C%20g%20%5C%20CaCO_%7B3%7D%7D%29%5C%5C%20%5C%5C%5Cboxed%20%7Bmol%20%5C%20CaCO_%7B3%7D%20%5C%20%3D%200.2498%20%5C%20mol%7D)
STEP 3: Use the stoichiometric ratio to determine the number of moles of CaO formed.
For every mole of calcium carbonate decomposed, one more of a calcium oxide is formed. Therefore,
![mol \ CaO \ = 0.2498 \ mol](https://tex.z-dn.net/?f=mol%20%5C%20CaO%20%5C%20%3D%200.2498%20%5C%20mol)
STEP 4: Convert the moles of CaO into mass of CaO using its molar mass.
![mass \ CaO \ = 0.2498 \ mol \ CaO \ (\frac{56.0774 \ g \ CaO}{1 \ mol \ CaO})\\ \\mass \ CaO \ = 14.008 \ g](https://tex.z-dn.net/?f=mass%20%5C%20CaO%20%5C%20%3D%200.2498%20%5C%20mol%20%5C%20CaO%20%5C%20%28%5Cfrac%7B56.0774%20%5C%20g%20%5C%20CaO%7D%7B1%20%5C%20mol%20%5C%20CaO%7D%29%5C%5C%20%5C%5Cmass%20%5C%20CaO%20%5C%20%3D%2014.008%20%5C%20g)
Since there are only 2 significant figures in the given, the final answer must have the same number of significant figures.
Therefore,
![\boxed {mass \ CaO \ = 14 \ g}](https://tex.z-dn.net/?f=%5Cboxed%20%7Bmass%20%5C%20CaO%20%5C%20%3D%2014%20%5C%20g%7D)
Learn More
- Learn more about stoichiometry brainly.com/question/12979299
- Learn more about mole conversion brainly.com/question/12972204
- Learn more about limiting reactants brainly.com/question/12979491
Keywords: thermal decomposition, stoichiometry
Answer:
endothermic
Explanation:
It is endothermic since it absorbs heat. If the reaction RELEASED heat (exothermic) the "+ heat" would be on the right side of the equation.
KI is the formula to potassium