Why would a scientific model change over time

How many atoms are there in 5.70 mol of mg

Which buffer would be better able to hold a steady ph on the addition of strong acid, buffer 1 or buffer 2? explain. buffer 1: a solution containing 0.10 m nh4cl and 1 m nh3. buffer 2: a solution containing 1 m nh4cl and 0.10 m nh3

Apropane torch is lit inside a hot air balloon during preflight preparations to inflate the balloon. which condition of the gas remains constant