12. Inspiration for new types of synthetic materials often comes from observations of 13. The practical use of scientific knowledge, as in the development of new synthetic materials, is
an example of
in action.
14.
In the formation of synthetic materials, natural materials undergo chemical reactions wherein
their
rearrange and form new molecules.

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

What is a possible quantum number set for an electron in the 3s orbital of a magnesium atom

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.