Answer:
B.) If sodium carbonate is added to vinegar, the reaction will absorb heat.
Explanation:
A.) is incorrect because this is not testable. Rather, it is just an opinion that cannot be proven correct or incorrect.
B.) is correct because this statement is testable. Tests need to be run to determine the accuracy of the statement.
C.) is incorrect because this statement explains something that does not need to be tested. It is an example of a physical change when one tears a piece of paper.
D.) is incorrect because this is already a true statement. It is obvious that not all reactions absorb/release heat. While tests could be run to further prove this statement true, it is already considered accurate.
Answer:
4
Explanation:
The balanced equation for the reaction is as follows:
4Al + 3O2 --> 2(Al2O3)
Equation is as follow,
Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂
Oxidation:
3 CO → 3 CO₂
Oxidation state of C in CO is +2, and that in CO₂ is +4. So, carbon has lost 2 electrons per mole and 6 electrons per 3 moles hence,
3 CO → 3 CO₂ + 6 e⁻
Reduction:
Fe₂O₃ → 2 Fe
Oxidation state of Fe in Fe₂O₃ is +3 per atom, and that in Fe is 0. So, Iron has gained 3 electrons per atom and 6 electrons per 2 atoms hence,
Fe₂O₃ + 6e⁻ → 2 Fe
Result:
Iron in Fe₂O₃ has been reduced in this reaction and has played a role of oxidizing agent by oxidizing carbon from +2 state to +4 state.
Explanation:
It is also important to note that potential energy can be positive, zero or negative. ... Now that the kinetic energy and potential energy have been defined, we can now apply the Law of Conservation of Energy. In other words, the kinetic energy plus the potential energy equals a constant (KE+PE=Constant).
