A scientist claims that a certain chemical will make fabric waterproof. Which option describes a controlled experiment that will produce evidence that will
support or refute her claim?
A. One group of fabric is treated with the chemical, and the other
group is not. Then each group is exposed to water.
B. One group of fabric is treated with a small amount of the
chemical, and the other group is treated with a large amount. Then
each group is exposed to water.
C. Two groups of fabric are treated with the chemical. One group is
cotton and the other is polyester. Then each group is exposed to
water.
D. Two groups of fabric are treated with the chemical. Then one
group is exposed to a small amount of water, and the other group
is exposed to a large amount.

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.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.