A, Heat will flow from the nickle to the water in the glass.
Answer:
the second layer of the atmosphere.
The half-life of a radioactive compound is the time taken for that said isotope to decay or disintegrate so that only half of the initial atoms remain in that compound. During the decay process, the isotope will give off energy and matter, and the way to depict this is indicated by t 1/2.
Answer: Mg is the excess reactant for the forward reaction.
Explanation: It is a stoichiometry problem and solved with the help of given grams and using balanced equation. Grams of both the reactants are converted to moles and divided by their coefficients. The excess reactant is the one for which we get the highest number on doing above steps.
The balanced equation is:

Molar mass of silicon tetra chloride is 169.9 gram per mol and the molar mass of Mg is 24.3 gram per mol.

= 

= 2.67 mol Mg
From balanced equation, the coefficient of silicon tetra chloride is 1 and that of Mg is 2. So, we will divide the moles of silicon tetra chloride by 1 and that of Mg by 2 and see which one gives highest number.
For silicon tetra chloride,
= 0.317
and for Mg,
= 1.34
The highest number is for Mg and so the excess reactant for the forward reaction is Mg.
It is a column of elements in the periodic table of the chemical elements.