An element has three isotopes: St-284 (34.60%), St-285 (21.20%), and St-288 (44.20%). What is its average atomic mass?

When will le chatelier's principle come into effect? at the beginning of a reaction, when there are only reactants when a reaction has reached chemical equilibrium when a catalyst is added to a reaction mixture when a reaction is occurring but not yet at equilibrium

If 34.2 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 299 kelvin and 1.21 atmospheres? 2 li (s) + 2 h2o (l) yields 2 lioh (aq) + h2 (g)

When an object falls through the air and encounters air resistance its overall speed will be than if it had not encountered air resistance? (one word answer)