List the controlled, independent and dependent variable of these chemical reactions.

Chemical Reactions:
-Iron and copper (II) sulfate solution
-Lead (II) nitrate and potassium iodide solutions
-Magnesium metal and hydrochloric acid solution
-Electrolysis of water
-Burning magnesium

The answer is tea due to the main ingredient being a herb that grows from the ground and sugar that grows from a stalk, i hope this : )     p.s.  can i be brainliest?

Heating it up with cause a quicker reaction time

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.