Given the incomplete equation representing a reaction: C_(3)H_(8)+5O_(2)arrow 3CO_(2)+underline ( )H_(2)O What is the coefficient of H2O when the equation is completely balanced using the smallest whole number coefficients? 1 2 4 8

To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation.<br /><br />Given the incomplete equation:<br />$C_{3}H_{8}+5O_{2}\rightarrow 3CO_{2}+\underline {\quad }H_{2}O$<br /><br />Step 1: Balance the carbon atoms.<br />There are 3 carbon atoms on the left side, so we need 3 carbon atoms on the right side. The coefficient for $CO_{2}$ is already 3.<br /><br />Step 2: Balance the hydrogen atoms.<br />There are 8 hydrogen atoms on the left side, so we need 8 hydrogen atoms on the right side. The coefficient for $H_{2}O$ is 4.<br /><br />Step 3: Balance the oxygen atoms.<br />There are 10 oxygen atoms on the right side (3 from $CO_{2}$ and 4 from $H_{2}O$), so we need 10 oxygen atoms on the left side. The coefficient for $O_{2}$ is already 5.<br /><br />Therefore, the coefficient of $H_{2}O$ when the equation is completely balanced using the smallest whole number coefficients is 4.<br /><br />Answer: 4