O2- indicates an ion of oxygen having two extra electrons. I.e., since an oxygen atom normally has 8 protons and 8 electrons, this ion has 10 electrons (-10 charge) and 8 protons (+8 charge) giving it a charge of -2 (-10 + 8 = -2).
The AC unit uses a refrigerant generally a chemical called freon to cool the air in a house. The unit evaporates freon and uses the result of this evaporation cycle to circulate cool air. ... Freon is a gas. The AC unit compresses this cool gas, causing it to become very hot.
Answer:
Here are three examples
Explanation:
In a reversible reaction, the conversions of reactants to products and of products to reactants occur at the same time.
Example 1
The reaction of hydrogen and iodine to from hydrogen iodide.
H₂ + I₂ ⇌ 2HI
Example 2
The dissociation of carbonic acid in water to form hydronium and hydrogen carbonate ions
H₂CO₃ + H₂O ⇌ H₃O⁺ + HCO₃⁻
Example 3
The dissociation of dinitrogen tetroxide to nitrogen dioxide.
N₂O₄ ⇌ 2NO₂
