Which of these changes produces a chemical change? O A. A stone fizzes and forms a gas when acid is dropped on it.
B. Limestone slowly dissolves in water and forms a cave.
O C. Lava cools and changes from a thick fluid to solid rock.
OD. A large rock is crushed into gravel.

Explanation:

Limestone (CaCO3) dissolves in water - with difficulty - but remains, and can be recovered as CaCO3

Solidifying lava and rock crushed to gravel are physical changes.

If acid dropped on a rock causes fizzing and gives of gas, that is a chemical reaction, e.g,

CaCO3 + 2HCl —> CaCl2 + H2O + CO2

Dissolution of limestone in water does result in dissociation into ions that may be hydrated, but CaCO3 is precipitated out as solutions become more concentrated.

CaCO3 + 2H2O —> Ca++ + CO3= + OH- + H3O+

velocity and height

measuring physical properties lab reportinstructions: in the physical properties lab, you will test the physical properties of different building materials in order to pick the appropriate materials for a new home in tiny world. record your observations and test measurements in the lab report below. youwill submit your completed report.name and title: lyric lawton, mr.herbert, 10/13/17, physical properties lab. objective(s): i need to parvus build his house out of the right material, so he will stay cool in the mountains.hypothesis: if we use wood to build the roof of the house, then the temperature inside the house will remain cooler.if we use clay brick to build the walls and floors of the house, then the temperature inside the house will remain cooler.if we use aluminium to bring electricity into the home, then it will allow electricity to flow into the home at a faster rate.if we use iron to construct the latches on the windows and doors, then the magnetism will keep the latches secure.