The trick for this problem is to understand atomic mass: the fact that different atoms have different masses. What we need to do is add up all the atomic masses of the compound and work out the ratio of mass of water to the mass of sodium carbonate. Atomic masses are often given for each atom in the periodic table, but you can look them up on google too.
You can do this by adding up individual atoms for each molecule, or you can shortcut and lookup the molar mass of the compound (i.e.the task already done for you).
The molar mass of water is 18.01g/mole so for 10 moles of water we have a mass of 180.1g.
The molar mass of sodium carbonate is 106g/mole (google).
So the total mass of the sodium carbonate decahydrate compound is 180.1+106 = 286.1g, of which water would make up 180.1g, so the percentage of water is is 180.1/286.1 = 0.629, so we can round this to 63%
:)
Answer:
Please find the complete question and its solution in the attached file:
Explanation:
The atom has only one isotope which means 100 % of same atom is present in nature. The atomic mass of an element is the number of times an atom of that element is heavier than an atom of carbon taken as 12. Mass of one atom of that isotope is 9.123 ✕ 10⁻²³ g, so mass of one mole of atom that is Avogadro's number of atom is 6.023 X 10²³ X 9.123 X 10⁻²³ g=54.94 g = 55 g (approximate).
So, the atom having atomic mass 55 will be Cesium (Cs). Only one isotope of Cesium is stable in nature.
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,
In writing the formula for a salt the symbol of the cation is first then the anion is written second .
