Now that we have put a coefficient of 2 in front of $NaNO _3$, what coefficient should go in front of $PbCl _2$ to balance lead $( Pb )$ ?
$Pb(NO_3)_2+NaCl \rightarrow ? PbCl_2+2 NaNO_3$
Express your answer numerically as an integer.
Answer (1)
Count the number of lead ( P b ) atoms on the left side of the equation: 1.
Count the number of lead ( P b ) atoms on the right side of the equation.
Balance the number of lead ( P b ) atoms on both sides of the equation by setting the coefficient in front of P b C l 2 to 1.
The coefficient in front of P b C l 2 is 1 .
Explanation
Analyzing the Chemical Equation Let's analyze the chemical equation to determine the coefficient for P b C l 2 to balance the lead ( P b ) atoms.
The unbalanced equation is:
P b ( N O 3 ) 2 + N a Cl → ? P b C l 2 + 2 N a N O 3
We need to find the coefficient in front of P b C l 2 .
Counting Lead Atoms First, let's count the number of lead ( P b ) atoms on the left side of the equation. In P b ( N O 3 ) 2 , there is 1 lead atom.
Now, let's look at the right side of the equation. We have P b C l 2 . To balance the lead atoms, the number of lead atoms on both sides must be equal.
Balancing Lead Atoms Since there is 1 lead atom on the left side ( P b ( N O 3 ) 2 ), we need to have 1 lead atom on the right side. The compound on the right side containing lead is P b C l 2 . If we put a coefficient of 1 in front of P b C l 2 , we will have 1 lead atom on the right side.
So, the balanced equation for lead is:
P b ( N O 3 ) 2 + N a Cl → 1 P b C l 2 + 2 N a N O 3
Final Coefficient Therefore, the coefficient in front of P b C l 2 should be 1 to balance the lead atoms.
Examples
Balancing chemical equations is crucial in various fields, such as environmental science, where it helps in understanding and controlling pollution. For example, when treating industrial wastewater containing lead compounds, it's essential to know the exact amount of chemicals needed to convert the lead into a less harmful form. By correctly balancing the chemical equation, scientists can accurately determine the required amount of reactants, ensuring efficient and safe treatment processes. This prevents both under-treatment, which leaves pollutants in the water, and over-treatment, which wastes resources and may create additional environmental problems. The balanced equation ensures that the reaction proceeds as expected, leading to the desired outcome.
