Answer:
firstly ,<u>GREEK PHILOSPHER </u><u>DEMOCRITUS </u>suggested that matter is composed of tiny particles called atom . In the beginning of 19th century <u>JOHN DALTON </u> put forward atomic theory . At the end of 19th century it was considered that atom can not be subdivided .
nucleus: directs
chromosome: genetic
chloroplasts: convert energy from sun
cell membrane: controls
cytoplasm: holds
If you change the subscripts it would change the reactants or products and then you would be solving a different formula, you would change what the chemical is
Answer:
a) Fe(s) + Ni^2+(aq) ----> Fe^2+(aq) + Ni(s)
b) no reaction
c) no reaction
d) 2Mg(s) + 2H2O(l)-----> 2Mg^2+(aq) + O2(g) +4H^+(aq)
e) no reaction
Explanation:
It is important to say here that the ability of a particular chemical specie to displace another chemical specie is dependent on the relative standard reduction potentials of the species involved.
All the reactions stated above are redox reactions. Let us take reaction E as an example. Mg^2+ has a reduction potential of -2.37 V while Cr^3+ has a reduction potential of -0.74V. Since the reduction potential of magnesium is more negative than that of chromium, there is no reaction when a piece of chromium metal is dipped into a solution of Mg^2+.
Similarly, though metals displace hydrogen gas from dilute acids, metals that are less than hydrogen in the reactivity series cannot do that. This explains why there is no reaction when copper and silver are dipped into dilute acid solutions.
Reaction occurs when iron is dipped into a nickel solution because the reduction potential of Fe^2+ is far more negative than that of Ni^2+.
