Small children are occasionally injured when they try to inhale helium from
a compressed helium tank. If a small child tries to transfer the contents of
a 50 L tank of helium at a pressure of 125 atm and a temperature of 20°
C into its lungs, how many moles of gas will it inhale?

he would use the colour black

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.

there are two significant figures.

the correct answer to this question is 2