He set up his periodic table by the atomic mass
(1) 14C also known as Carbon-14, is used to radio-date organic materials as well as earth materials.
I would say the energy has to be decreased by 87 kj because the bonding is held together by 87 kj so removing that should prevent the bonding from taking place or reverse it I believe. In other words, a certain amount of energy is required to hold the bond together and in the absence of that energy, the bonding will not take place.
The correct answer among the choices given is the last option. A mixture has particles that cannot be seen but do reflect light. It should be classified as a colloid. A colloid is a mixture in which one substance is suspended throughout another substance.