What is the difference between the molar mass and the empirical formula mass of a compound? when are these masses the same, and when are they different? when different, how is the molar mass related to the empirical formula mass?

During which time interval does the object travel approximately 10 meters

Liquid ammonia is produced at high temperatures and under great pressure in a tank by passing a mixture of nitrogen gas and hydrogen gas over an iron catalyst. the reaction is represented by the following equation. n2(g) + 3h2(g) → 2nh3(g) changing all but one experimental condition will affect the amount of ammonia produced. that condition is a) increasing the concentration of both reactants b) changing the temperature within the tank c) decreasing the pressure within the tank. d) increasing only the amount of nitrogen present.

When did stem cell research become known ? who discovered stem cell? what experiments or studies have been conducted so far?