Counting gives an exact number and exact numbers have infinite sig figs.
Answer: b. 
is positive and 
is positive.
Explanation:-
As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of 
in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e. is positive.
The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e. is positive.
Answer:
All of the above
Explanation:
All of this is in the solar system.
Answer:
6 oxygen atoms
Explanation:
From the equation,
2Fe(OH)₃ → Fe₂O₃ + 3H₂O
From the reactant (left hand side) we have 2 moles of Fe(OH)₃ having (2 * 3 = 6) atoms of oxygen and decomposed to give Fe₂O₃ which contains 3 atoms of oxygen and 3 moles of water that also contains 3 atoms of oxygen.
Since the number of oxygen participating in the reaction is independent on the product (not a reversible reaction) then the total number of oxygen atoms participating in the reaction is 6
