What happens to temperature and pressure when altitude increases?

temperature decreases and pressure also decreases

Explanation:

Temperature - As you increase in elevation, there is less air above you thus the pressure decreases. As the pressure decreases, air molecules spread out further (i.e. air expands), and the temperature decreases. If the humidity is at 100 percent (because it's snowing), the temperature decreases more slowly with height.

Pressure - As altitude rises, air pressure drops. In other words, if the indicated altitude is high, the air pressure is low. This happens for two reasons. ...As altitude increases, the amount of gas molecules in the air decreases—the air becomes less dense than air nearer to sea level.

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.