4 type of molecular models

Select the equations below that represent physical changes. Choose one or more: A. 2 H2O (l) → 2 H2 (g) + O2 (g) B. H2O (l) → H2O (s) C. CO2 (s) → CO2 (g) D. H2 (g) → 2 H (g)

Are Si valence electrons shared? Are C valence electrons shared?

Practice of leaving the stalks of crops in the ground to anchor topsoil

The elements in groups 3-12 are known as: A. The transition elements. B. The halogens. C. The noble gases. D. The alkali earth metals.

Does cornstarch bubble up when mixed with vinegar.

Which statement regarding water is true? Energy must be given off in order to break down the crystal lattice of ice to a liquid. Hydrogen bonds are stronger than covalent bonds. Liquid water is less dense than solid water.

Which of the following elements has the fewest valence electrons?. a. beryllium. b. boron. c. carbon. d. lithium

How many molecules are in 4.50 moles of H2O? A. 450 molecules B. 6.02 x 1023 molecules C. 2.71 x 1024 molecules D. 3.00 molecules

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 45.0 g of calcium fluoride

If the mass of a material is 111 grams and the volume of the material is 11 cm3, what would the density of the material be?