Answer:
A voltaic cell
Explanation:
A voltaic cell is a device which converts chemical energy to electrical energy. The chemical reactions that take place inside the cell causes electrons to flow from anode to cathode hence, electricity is produced. A simple voltaic cell is made by placing two different metals in contact with an electrolyte separated by a salt bridge. The cathode is the negative electrode while the anode is the positive electrode. It is also called a galvanic cell.
In a voltaic cell having a copper/copper solution half cell, reduction occurs at the cathode. Hence, at the cathode copper II ions accept two electrons and become reduced to ordinary metallic copper. This causes the blue colour of the solution to become discharged (fade) as the cell continues to function.
Answer:
Hydrogen peroxide should be stored in
1) a cool environment
2) with amber bottles away from sunlight
3) with little drops of sodium phosphate
Explanation:
It has been confirmed that heat and light aids in the decomposition of hydrogen peroxide according to the equation; 2H2O2→2 H2O + O2.
This means that hydrogen peroxide must be stored in a cool place. This will reduce its rate of decomposition. Secondly, it should be stored in amber bottles away from light since light also aids in its decomposition.
Thirdly, drops of sodium phosphate may be added to prevent its catalytic decomposition during storage.
Answer:
Explanation:
The half-life of K-40 (1.3 billion years) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction
<u>half-lives</u> <u> t/yr </u> <u>Remaining</u>
0 0 1
1 1.3 billion ½
2 2.6 ¼
3 3.9 ⅛
We see that after 2 half-lives, ¼ of the original mass remains.
Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.
Original mass = 4 × 2.10 g = 
Answer : The balanced half-reaction in a basic solution will be,
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Rules for the balanced chemical equation in basic solution are :
First we have to write into the two half-reactions.
Now balance the main atoms in the reaction.
Now balance the hydrogen and oxygen atoms on both the sides of the reaction.
If the oxygen atoms are not balanced on both the sides then adding water molecules at that side where the more number of oxygen are present.
If the hydrogen atoms are not balanced on both the sides then adding hydroxide ion
at that side where the less number of hydrogen are present.
Now balance the charge.

- Now balance the oxygen atoms.

- Now balance the hydrogen atoms.


The balanced half-reaction in a basic solution will be,

Explanation:
Below is an attachment containing the solution.