Automotive air bags inflate when sodium azide decomposes explosively to its constituent elements:
2 NaN3(s) → 2 Na(s) + 3 N2(g)
How many moles of N2 are produced by the decomposition of 1.25 mol of sodium azide?

1.875 moles

Explanation:

2 NaN3(s) → 2 Na(s) + 3 N2(g)

From the equation above, Sodium azide has a chemical formula of NaN3 while nitrogen gas has a chemical formula of N2.

Therefore, If on decomposition

2 moles of NaN3 produce 3 moles of N2

1.25 mol of NaN3 produce Z moles of N2

To get the value of Z, cross multiply

Z x 2 moles = 3 moles x 1.25 moles

2 moles•Z = 3.75 moles²

Divide both sides by 2 moles

2 moles•Z/2 moles = 3.75 moles²/2 moles

Z = 1.875 moles

Thus, 1.875 moles of N2 are produced by the decomposition of 1.25 mol of sodium azide

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.