<span>The law of conservation of energy states that energy can neither be created nor destroyed - it can only be converted from one form to another. It basically means that energy can't just appear, but has to be converted from existing energy; for example, the chemical energy in petrol is turned into electrical energy to power a car.Remember the total energy of universe is constant,,and no more energy can be drawn from out if we collect all universe's energy at a single point(its the big bang energy splitted during </span>
The proper way to chemically write carbon dioxide is CO2
The most electronegative element will have atoms with strongest association for electrons. Electronegativity is the ability of an atom to attract electrons and form bonds with electrons. . In the periodic table the left hand side favors the loss of electrons because less energy is required to lose an electron than to gain an electron. On the other han, the right hand side favors gaining electrons since less energy is required than when losing electrons.
Henceforth, from left to right in the periodic table the tendency to gain electrons increases. In contrast, going down a group there is decreased association for electrons, because atomic radius increases which suggests that valence electrons are further away from the nucleus.This makes fluoride the ion with strongest association of electrons. The noble gases have a complete shell so cannot attract electrons to themselves, which means they have no electronegativity.
"A" is the answer. The chemical reaction is when the batter becomes brown.
B is mixing C is mass becoming a liquid and D. is dissolving no chemical reaction happened there.
Hope that helps!