The rate law for the reaction nh4(aq)+ + no2(aq)- → h2o(l) + no2(g) is rate = k [nh4+][no2-], and the value of k is 2.7*10-4 m-1s-1. what is the rate of reaction when [nh4+] = 0.050 m and [no2-] = 0.25 m?

The answer for #3 is c but i don't know why

You have 125g of a certain seasoning and are told that it contains 76.0 g of salt what is the percentage of salt by mass in this seasoning

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?