Final answer:
In the electrochemical galvanic cell, electrons flow from the anode to the cathode. One copper atom loses two electrons, which reduce two silver ions at the cathode. Over time, the copper anode decreases in mass while the silver cathode increases in mass.
Step-by-step explanation:
The electrochemical cell you are asking about involves the flow of electrons, changes in mass of the electrodes, and the role of anode and cathode. Here is a detailed explanation:
Electrons always flow from the anode to the cathode in an electrochemical galvanic cell. The anode is where oxidation occurs, losing electrons, and the cathode is where reduction occurs, gaining electrons. Therefore, statement 1 is false.
For each copper atom that is oxidized to copper ions (Cu to Cu²⁺), two electrons are lost. In the cathode half-cell, these two electrons are used to reduce two silver ions to two silver atoms (2Ag⁺ to 2Ag). Therefore, statement 2 is false as the stoichiometry is one copper atom to two silver ions.
Over time, the copper bar, which acts as the anode, decreases in mass because copper atoms are oxidized and go into solution as copper ions. The silver bar, which is the cathode, increases in mass because silver ions are reduced and deposit as silver atoms on the bar. Therefore, statement 3 is true.
Since the silver bar is where reduction takes place, it is the cathode, not the anode. Thus, statement 4 is false.
Summarily, the true statement here is that over time, the copper bar disappears and the silver bar gets bigger.