Answer is: mass of unused sulfur is 5.87 grams.
Balanced chemical reaction: C + 2S → CS₂.
m(C) = 12.0 g; mass of carbon.
m(S) = 70.0 g; mass of sulfur.
n(C) = m(C) ÷ M(C).
n(C) = 12 g ÷ 12 g/mol.
n(C) = 1 mol; amount of substance.
n(S) = m(S) ÷ M(S).
n(S) = 70 g ÷ 32.065 g/mol.
n(S) = 2.183 mol.
From chemical reaction: n(C) : n₁(S) = 1 : 2.
n₁(S) = 1 mol · 2 = 2 mol.
Δn(S) = n(S) - n₁(S).
Δn(S) = 2.183 mol - 2 mol.
Δn(S) = 0.183 mol; amount of unused sulfur.
Δm(S) = 0.183 mol · 32.065 g/mol.
Δm(S) = 5.87 g.
Out of the choices given, the one that describes a substance whose atoms all have the same number of protons are an element. The correct answer will be B.
Answer: A. uranium salt
Becquerel made a conclusion that it was the uranium that causes the images found in the photographic plates. Though his theory was disproved during the first time,he continued to develop it. Then, it is through this experiment that Becquerel discovered radioactivity.
<span>Very quick oxidation reactions result in combustion.
Reason
Oxidation reaction involved reaction with oxygen. Consider following example:
C6H12O6 + 6O2 </span>→ 6CO2 + 6H2O
(glucose) (carbon dioxide)
From the above reaction, it can be seen that, oxidation state of C in glucose in zero, while that in CO2 is +4. Thus, oxidation state of C is increased from 0 to +4. This process is called oxidation. Further, complete oxidation of reactant molecule is referred as combustion.
