An athlete can apply an instant cold pack after an injury to help reduce swelling. An instant cold pack is a small bag containing two pouches, one filled with water and the other filled with ammonium nitrate (NH4NO3). The athlete activates the pack by squeezing the bag to break the pouches open, allowing the water and ammonium nitrate to mix. When this happens, the ammonium nitrate dissolves in the water, forming ammonium ions (NH4+) and nitrate ions (NO3−), and the pack becomes cold. Is this chemical exothermic or endothermic?

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

Which of the following are sources of revenue for media companies? a. direct sales to producers b. advertising and subscriptions c. online purchase d. capital investments

Which of these is an example of pseudoscience? a) predicting the time of sunrise based on data on position of earth b) predicting the date of the moon phases based on data on position of earth c) predicting eclipses based on the position of the sun and the moon d) predicting future events in a person's life based on the position of the moon