Consider the following intermediate chemical equations:
[tex]$\begin{array}{l}
2 H_2(g)+O_2(g) \rightarrow 2 H_2 O(l) \
H_2(g)+F_2(g) \rightarrow 2 HF(g)
\end{array}$[/tex]
In the final chemical equation, HF and [tex]$O _2$[/tex] are the products that are formed through the reaction between [tex]$H _2 O$[/tex] and [tex]$F _2$[/tex]. Before you can add these intermediate chemical equations, you need to alter them by multiplying the
A. second equation by 2 and reversing the first equation.
B. first equation by 2 and reversing it.
C. first equation by (1 / 2) and reversing the second equation.
D. second equation by 2 and reversing it.
Answer (2)
To obtain the target equation where H2O and F2 form HF and O2, we need to reverse the first equation and multiply the second equation by 2. This allows us to align the reactants and products correctly. Thus, the correct choice is to multiply the second equation by 2 and reverse the first equation.
;
Reverse the first equation to have H 2 O as a reactant.
Multiply the second equation by 2 to obtain 4 H F as a product.
Adding the modified equations results in the desired final equation.
Therefore, the correct answer is multiplying the second equation by 2 and reversing the first equation. $\boxed{second equation by 2 and reversing the first equation.}
Explanation
Understanding the Problem We are given two intermediate chemical equations and asked how to manipulate them to arrive at a final equation where H 2 O and F 2 react to form H F and O 2 . This means we need to reverse the first equation to get H 2 O on the reactant side and multiply the second equation to get H F on the product side.
Target Reaction The target reaction is: 2 H 2 O ( l ) + 2 F 2 ( g ) → 4 H F ( g ) + O 2 ( g )
Reversing the First Equation The first intermediate equation is: 2 H 2 ( g ) + O 2 ( g ) → 2 H 2 O ( l ) To get 2 H 2 O on the reactant side, we reverse the equation: 2 H 2 O ( l ) → 2 H 2 ( g ) + O 2 ( g )
Multiplying the Second Equation The second intermediate equation is: H 2 ( g ) + F 2 ( g ) → 2 H F ( g ) To get 4 H F as a product, we multiply the equation by 2: 2 H 2 ( g ) + 2 F 2 ( g ) → 4 H F ( g )
Adding the Equations and Conclusion Adding the modified equations: 2 H 2 O ( l ) → 2 H 2 ( g ) + O 2 ( g ) 2 H 2 ( g ) + 2 F 2 ( g ) → 4 H F ( g ) Adding them gives: 2 H 2 O ( l ) + 2 F 2 ( g ) → 4 H F ( g ) + O 2 ( g ) Therefore, the first equation needs to be reversed, and the second equation needs to be multiplied by 2.
Examples
In chemical engineering, manipulating and combining chemical equations is crucial for designing industrial processes. For instance, when synthesizing a desired compound, chemists often break down the overall reaction into a series of intermediate steps. By understanding how to reverse and scale these intermediate equations, engineers can optimize reaction conditions, maximize product yield, and minimize waste. This process ensures efficient and cost-effective chemical production.
