In: Chemistry
how does the mass of the reactants compare to the mas of the products with drops of calcium chloride solutions and a few drops of carbonate solutions and B. with 1/4 of an Alka Seltzer and 10.0 ml water and with sodium hydroxide solution with phenolphthalein with hydrochloric acid. discuss
The mass of the reactant and product can be calculated by weighing the reactant before reaction and after reaction.
a. In first example the reaction of CaCl2 with Na2CO3. Take a clear clean beaker and add the 10ml of distilled water and placed in over the balance. Add the reactants to the beaker containing water and record the weight immediately. Stir the solution for 1-2minutes and record the weight. Check for any weight difference in the before the reaction and after 1-2 min of reaction.
In this example there is no difference in weight,
CaCl2 + Na2CO3. -> CaCO3 + 2NaCl
All the constituents CaCl2 + Na2CO3 convert to CaCO3 + 2NaCl and there is no escape of small molecules.
b. Reaction of ¼ part of Alka Seltzer tablet with water
Take 10 ml of water in a sealed container and weigh, add ¼ portion of Alka seltzer tablet and record the weight immediately in closed state. Shake the container for 5min and weigh again. We can’t find any weight difference. Open the lid of container, close and weigh. There will be a weight difference.
Reason: the reaction of Alka seltzer with water liberates the carbon dioxide molecule
In the first instance the weighed after reaction in the closed state It accounts for CO2molecules but once the lid is open the CO2 molecules escapes to reduce the weight.
c. The same experiment as in case of (a). The Phenolphthalein with HCl there is no reaction so there is no weight difference to after reaction and before reaction