What type of reaction is the following: BaCO3 → BaO + CO2

Can someone me with 3 and 4 plz. this is for masteries test.

What is dhmo? hint: you find it everywhere something is wet..

Which statement is true according to the kinetic theory? a. molecules of different gases with the same mass and temperature always have the same average density. b. molecules of different gases with the same mass and temperature always have the same average volume. c. molecules of different gases with the same mass and temperature always have the same pressure. d. molecules of different gases with the same mass and temperature always have the same molecular mass. e. molecules of different gases with the same mass and temperature always have the same average kinetic energy.