(a tablet containing calcium carbonate and fillers with a mass of 1.631 g was dissolved in hcl. after the fillers were filtered out, the hcl was neutralized by adding sodium carbonate. the resulting precipitate was pure calcium carbnonate (with the fillers removed). the solid calcium carbonate was collected on a watch glass that had a mass of 46.719 g when empty. after teh calcium carbonate had been allowed to dry, the mass of the watch glass plus product was found to be 47.544 g.

1. what is the mass of pure calcium carbonate product collected at the end of the experiment?

2. calculate the mass % calium carbonate in the tablet.

3. calculate the mass percent calcium in calcium carbonate. this calculation is theoretical and is independent of the data provided.

4. calculate the number of grams of calcium that were in the tablet.

(hint: this can be obtained by using the answers to question 1 and 3)

1) 0.825 grams is the mass of pure calcium carbonate product collected at the end of the experiment.

2) The mass % calcium carbonate in the tablet is 50.58%.

3) The mass % of calcium in calcium carbonate  is 40.00 %.

4) Mass of calcium in a tablet is 0.33 g.

Explanation:

Mass of tablet = 1.631 g

Mass of the watch glass = 46.719 g

Mass of the watch glass + mass of calcium carbonate = 47.544 g.

Mass of calcium carbonate = 47.544 g - 46.719 g = 0.825 g

0.825 grams is the mass of pure calcium carbonate product collected at the end of the experiment.

Mass of calcium carbonate = 0.825 g

Percentage of calcium in tablet:

The mass % calcium carbonate in the tablet is 50.58%.

Percentage of calcium in calcium carbonate :

Molar mass of calcium carbonate = 100 g/mol

Atomic mass of calcium = 40 g/mol

Percentage of calcium in calcium carbonate :

The mass % of calcium in calcium carbonate  is 40.00 %.

Mass of calcium carbonate = 0.825 g

The mass % of calcium in calcium carbonate  is 40.00 %.

Mass of calcium in a tablet : x

Mass of calcium in a tablet is 0.33 g.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )