(a) Briefly describe a twin and a twin boundary. (b) Cite

Principles of General Chemistry 2
Problem 88P The bond angles in the nitrite ion, nitrogen dioxide, and the nitronium ion (NO2+) are 115, 134, and 180, respectively. Explain these values using Lewis structures and VSEPR theory.

Chemistry 11
The men's world record for running a mile outdoors (as of 1999) is 3 min 43.13 s. At this rate, how long would it take to run a 1500-m race? (1 mi = 1609 m.)

Chemistry: Matter & Change 1
Graph Create a graph that illustrates the law of multiple proportions.

Biology 8
The reactivity of an atom arises from a. the average distance of the outermost electron shell from the nucleus. b. the existence of unpaired electrons in the valence shell. c. the sum ofthe potential energies of all the electron shells. d. the potential energy of the valence shell. e. the energy diff

Anatomy & Physiology 1
In which direction would an MRI scanner move to produce sequential images of the body in the frontal plane, and in which direction would an MRI scanner move to produce sequential images of the body in the sagittal plane?

Biology for AP Courses
Plasmodesmata in vascular plants and gap junctions and animals are examples of specialized features of the cell. Mechanisms by which transport occurs between cells evolved independently within several eukaryotic clades. Explain, in terms of cellular cooperation, the selective advantages provided by s

Plant Systematics 3
What is the difference between parallel and penni-parallel? Between pinnate-netted, palmatenetted, and ternate-netted?

Chemistry for today : general, organic, and biochemistry 9
Why is the study of chiral molecules important in biochemistry?