The percent by mass sugar of a solution : 11.07%
<h3>Further explanation</h3>
Given
mass of sugar = 12.45 g
mass of water = 100 g
Required
The percent by mass
Solution
Mass of solution :

Percent mass of sugar :

The ionic formula of sodium oxide would be Na20
<u>Answer:</u> The atomic symbol of the given element is 
<u>Explanation:</u>
The general isotopic representation of an element is given as: 
where,
Z represents the atomic number of the element
A represents the mass number of the element
X represents the symbol of an element
For the given isotope: 130-iodine
Mass number = 130
Atomic number = 53
Hence, the atomic symbol of the given element is 
To balance the the chemical reaction, the number of moles
per element is balance is both side of the reaction and also the charge in both
sides of the reation. to balnce the reaction:
S2O3 2- + Cu 2+ ---> S4O6 2- + Cu+
2S2O3 2- + Cu 2+ ---> S4O6 2- + Cu+ + e