Answer:
Option A:
Zn(s) + Cu^(2+) (aq) → Cu(s) + Zn^(2+)(aq)
Explanation:
The half reactions given are:
Zn(s) → Zn^(2+)(aq) + 2e^(-)
Cu^(2+) (aq) + 2e^(-) → Cu(s)
From the given half reactions, we can see that in the first one, Zn undergoes oxidation to produce Zn^(2+).
While in the second half reaction, Cu^(2+) is reduced to Cu.
Thus, for the overall reaction, we will add both half reactions to get;
Zn(s) + Cu^(2+) (aq) + 2e^(-) → Cu(s) + Zn^(2+)(aq) + 2e^(-)
2e^(-) will cancel out to give us;
Zn(s) + Cu^(2+) (aq) → Cu(s) + Zn^(2+)(aq)
The answer would be D. The only minerals harder than corundum is diamond.
Answer:
0.025536g
Explanation:
no. of mole = mass/Mr
mass = Mr × no. of mole
= [23 + 1 + 12 + 3(16)] × 3.04×10^-4
= 0.025536g
= 0.0255g (3 significant figures)
When elements are combined to form compounds, they undergo chemical change in which the properties of the composing elements are always different from the compounds formed after reaction. The change is not only applicable to the chemical properties of the elements but also the physical states of the substances. Answer then is B.