Asugar solution is being evaporated in a triple-effect evaporator using saturated steam at 230 kpa. the pressure in the vapour space of the last effect is 32.7 kpa (abs). the overall heat transfer coefficients are u1 2.55, u2 2.2 and us 1.6 kw/m2k. the heat transfer areas are equal. the bpr in each effect are 0.66 c, 1.2 c and 2.1 respectively. no temperature adjustments are required to be made. 2.1. determine the boiling points in all three effects.

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.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.