The determination in problem 15-9 was modified to use the standard-addition method. in this case, a 3.925-g tablet was dissolved in sufficient 0.10 m hcl to give 1.000 l. dilution of a 20.00-ml aliquot to 100 ml yielded a solution that gave a reading of 415 at 347.5 nm. a second 20.00-ml aliquot was mixed with 10.0 ml of 50-ppm quinine solution before dilution to 100 ml. the fluorescence intensity of this solution was 503. calculate the percentage of quinine in the tablet.

"the periodic table is arranged in order of atomic number."

hurricanes form in warm water

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.