What metals will react with hydrochloride acid to yield hydrogen gas

I don’t know if this helps or not I’m still Not used to answering questions on These metals — beryllium, magnesium, calcium and strontium — react with hydrochloric acid to form a chloride and free hydrogen. Metallic magnesium when combined with hydrochloric acid, will naturally result in magnesium chloride -- used as a dietary supplement -- with the hydrogen being released as a gas.

Yes it would be a physical change.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .