Question

hydrochloric acid and magnesium were placed in a flask. a stopper with a hole was placed on the flask that allowed a piece of tubing and a gas syringe to collect a gas that was created with the change. identify one way to check and see if this was a chemical change. a seperate the mixture into two parts b put the mixture in the freezer c seal the hole in the flask d measure the temperature of the mixture

Explanation:

Chemical changes often involve energy transfer, such as heat. Measuring the temperature can show if there is an energy - related change characteristic of a chemical reaction. Separating the mixture (A) is a physical separation method and doesn't indicate a chemical change. Putting the mixture in the freezer (B) is a physical change related to temperature change of substances and not a way to identify a chemical change. Sealing the hole (C) doesn't help in identifying if a chemical change has occurred.

Answer:

D. Measure the temperature of the mixture