Answer:
C. 70%
Explanation:
Atomic Mass of the silicon = 28 g.
Atomic mass of the Carbon = 12 g.
Total mass of the Silicon Carbide = 28 + 12
= 40 g.
Now, Using the formula.
% Composition = Mass of the silicon/Total mass of the compound × 100 %
= 28/40 × 100 %
= 70 %
Hence, % composition of the silicon in SiC is 70%
Answer:
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Explanation:
when the molten outer core cools and become solid ,a very long time in future,the earth's magnetic field will disappear
Answer:
be able to meet long term timber needs.
Explanation:
Forest Services has been indicated for a long time the exhaustion of timer in the United States. However, in the recent decade, this trend has shown a reverse. The creation of nuclear energy and other technological developments that bring about drastic changes in our way of life. Gradually, the forest has recovered its trees and plants, and it is anticipated that timber will be available to meet long-term wood needs.
Reactants are the starting substances and products are the ending substances in a chemical reaction.
The atoms in reactants are arranged one way and are rearranged in a different way to form the products (in other words, reactants are chemically different from products).
The properties of reactants differ from the properties of products. Good answer for E.DG.

Explanation:
Concentration
;
The reaction see a
change in pressure per second. By the ideal gas law, this quantity would correspond to a change in concentration,
of

where the ideal gas constant
.
By definition, 
Therefore, for this particular reaction
