Substances that are not chemically bonded are mixtures.
Conservation of mass can be checked in an experiment . There are three steps to do it in a best way:
1. Weigh all the equipment and materials required in the experiment before the experiment.
2. Avoid spillage and evaporation during the experiment.
3. Weigh all the equipment and materials after the experiment.
If the mass is conserved then weight from step 1 is equal to weight from step 3.
A electrochemical reaction is said to be spontaneous, if
Answer 1:
Consider reaction: <span>Ni^2+ (aq) + S^2- (aq) ----> + Ni (s) + S (s)
The cell representation of above reaction is given by;
</span>

Hence,

we know that,

and

Therefore,

= - 0.25 - (-0.47) = 0.22 v
Since,
is positive, hence cell reaction is spontaneous
.....................................................................................................................
Answer 2: Consider reaction: <span>Pb^2+ (aq) +H2 (g) ----> Pb (s) +2H^+ (aq)
</span>
The cell representation of above reaction is given by;

Hence,

we know that,

and

Therefore,

= - 0.126 - 0 = -0.126 v
Since,
is negative, hence cell reaction is non-spontaneous.....................................................................................................................
Answer 3:
Consider reaction: <span>2Ag^+ (aq) + Cr(s) ---> 2 Ag (s) +Cr^2+ (aq)
</span>
The cell representation of above reaction is given by;

Hence,

we know that,

and

Therefore,

= - 0.22 - (-0.913) = 0.693 v
Since,
is positive, hence cell reaction is spontaneous
In 1 molecule of the compound C₆H₁₂O₂ there are 12 moles of hydrogen atoms
<h3>Further explanation</h3>
Given
C₆H₁₂O₂ compound
Required
moles of Hydrogen
Solution
In a compound, there is a mole ratio of the constituent elements.
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
In the C₆H₁₂O₂ compound, there are 3 forming elements: C, H and O
The number of each element is indicated by its subscript
C: 6 moles
H = 12 moles
O = 2 moles