How does the law of conservation of mass apply to this reaction c2h4 + o2 > 2h2o + 2co2 ?
a. only the oxygen needs to be balanced
b. the equation needs to be balanced. there are fewer oxygen atoms in the equation than hydrogen and carbon
c. the law of conservation of mass has already been applied
d. each element needs to be balanced

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)