When chemical reactions occur, the physical and chemical properties of the reactants are the same as the properties of the productsthe physical and chemical properties of the products are different from the reactantsthe compounds can be separated by physical meansa phase change takes place

the physical and chemical properties of the products Are different from the reactants. This causes the changes to be seen, physical changes and chemical.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa