A solution of hydrochloric acid is placed on a balance. Magnesium metal is added and the mass is recorded. The solution is stirred and the mass of the solution is recorded every 10 minutes. The following data is collected:
Time (mins) Mass of Hydrochloric Acid and Magnesium (g)
0 160.0 g
10 156.5 g
20 152.0 g
30 147.5 g
40 142.5 g
What does the data show is occurring?
The hydrochloric acid and magnesium metal react to form a soluble compound.
The hydrochloric acid and magnesium metal do not react.
The hydrochloric acid and magnesium metal react to form a precipitate.
The hydrochloric acid and magnesium metal react to form a gas.

Remember conservation of mass.  Mass can't just suddenly show up or disappear.  It has to come from somewhere, and it has to go somewhere.The mass of this mixture/solution is decreasing as time goes on. That means that some mass is going somewhere, out of the dish and away off the scale.-- React to form a soluble compound ?       Maybe, but that doesn't take mass away-- They don't react ?        Maybe, but that doesn't take mass away-- React to form a precipitate ?        Maybe, so big deal.  It sinks to the bottom. It doesn't take mass away.-- React to form a gas ?         If that happens, then the gas carries mass away !        That must be it !

Answer:The hydrochloric acid and magnesium metal react to form a gas.Explanation:i got it on study island