A methylene molecule (Fig. 8.17) contains one atom of carbon

(C) and two atoms of hydrogen (H), and is thus written as CH2. The distance from the C atom to each H atom is 1.085

ångströms (Å).

a. Using the fact that 1 Å is 0.1 nm, write the bond length in metres, using scientific notation.

b. If the C atom has coordinates(0, 0), the first H atom (called H

1

) has coordinates (1.085, 0) and the second H atom

(called H2

) has coordinates (−0.6941, 0.8339), calculate the bond angle, θ, as illustrated in Fig. 8.17.

c. Calculate the distance (in Å) between the two H atoms.

d. If the methylene molecule is now distorted so that the bond angle is decreased to 100 degrees, what is the new position of the H2 atom? (Assume that the positions of the C atom and the H1 atom remain unchanged.)