Cuantos Electrones gano o perdió si pasa de -1 a +5

Find the mass in grams of hydrogen gas produced when 14.0 moles of hcl is added to an excess amount of magnesium.

Atank contains 240 liters of fluid in which 10 grams of salt is dissolved. brine containing 1 gram of salt per liter is then pumped into the tank at a rate of 6 l/min; the well-mixed solution is pumped out at the same rate. find the number a(t) of grams of salt in the tank at time t.

What effect does nuclear radiation have on atoms?