A polar molecule is when the arrangement of the atoms in molecules are unequal where one end of the molecule has a positive charge while the other end has a negative charge. Examples of a polar molecule are water, ammonia, hydrogen sulfide and sulfur dioxide. The opposite is called a nonpolar molecule.
Let's use the example: H2O ---> H2 + O2
We find how many elements of a product are on one side and how many elements on the other side.
Reactant: H=2 O=1
Product: H=2 O=2
We need to make the same amount of hydrogen and oxegyn atoms on each side, regardless of how high the numbers are, and we do this by adding coefficients to the compounds.
Reactant: H=4 O=2
Product : H=4 O=2
2 H2O---> 2 H2 + O2
Answer: S8(s) + 8O2(g) → 8SO2(g) ΔH = -2368 kJ a.
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