A student adds about three grams of magnesium chloride to a large beaker of water. After stirring, the magnesium chloride crystals seem to have disappeared, and the liquid is clear. The student has prepared
A.
a heterogeneous mixture.
B.
a pure substance.
C.
a homogeneous mixture.
D.
a chemical reaction.

One of the hopes for solving the world's energy problem is to make use of the fusion reaction 21h +31h --> 42he + 10n + energy how much energy is released when 1 mol of deuterium is fused with 1 mol of tritium according to the above reaction? the masses of the atoms and the neutrons are as follows: 21h = 2.0140 amu 31h = 3.01605 amu 42he = 4.002603 amu 10n = 1.008665 amu. the speed of light is 2.9979 x 108 m/s.