How many grams of NaCl are needed to prepare 60 g of a 6.0% solution?

3.6 grams of NaCl are needed

Explanation:

Percent solution are solutions whose concentrations are expressed in percentages. The amount(either weight or volume) of a solute is expressed as a percentage of the total weight or volume of solution. Percent solutions can either be expressed as  weight/volume % (wt/vol % or w/v %), weight/weight % (wt/wt % or w/w %), or volume/volume % (vol/vol % or v/v %).

A 6.0% wt/wt % solution contains 6 g of solute in 100 g of solution

Therefore, a 100 g solution contains 6.0 g of solute.

60 g of 6.0% solution will contain  60 g solution * 6.0 g solute/ 100 g solution

Mass of NaCl present =  3.6 g  of NaCl

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.