Consider the following intermediate chemical equations:
[tex]$\begin{array}{l}
CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(g) \
2 H_2 O(g) \rightarrow 2 H_2 O(l)
\end{array}$[/tex]
Which overall chemical equation is obtained by combining these intermediate equations?
A. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+2 H _2 O ( I )$[/tex]
B. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+2 H _2 O ( g )$[/tex]
C. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+4 H _2 O ( g )+2 H _2 O ( l )$[/tex]
D. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+ BH _2 O ( g )$[/tex]
Answer (2)
Add the two given chemical equations.
Cancel out the common term 2 H 2 O ( g ) from both sides of the equation.
The overall chemical equation is C H 4 ( g ) + 2 O 2 ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( l ) .
The final answer is C H 4 ( g ) + 2 O 2 ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( l ) .
Explanation
Understanding the Problem We are given two chemical equations:
C H 4 ( g ) + 2 O 2 ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( g )
2 H 2 O ( g ) i g h t ha r p oo n u p 2 H 2 O ( l ) We want to find the overall chemical equation by combining these two equations.
Adding the Equations To find the overall equation, we add the two equations together: C H 4 ( g ) + 2 O 2 ( g ) + 2 H 2 O ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( g ) + 2 H 2 O ( l )
Cancelling Common Terms Now, we identify and cancel out any common terms that appear on both sides of the equation. In this case, 2 H 2 O ( g ) appears on both sides, so we can cancel it out: C H 4 ( g ) + 2 O 2 ( g ) + 2 H 2 O ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( g ) + 2 H 2 O ( l ) This simplifies to: C H 4 ( g ) + 2 O 2 ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( l )
Final Overall Equation The overall chemical equation obtained by combining the intermediate equations is: C H 4 ( g ) + 2 O 2 ( g ) i g h t ha r p oo n u pC O 2 ( g ) + 2 H 2 O ( l )
Examples
Consider a scenario where methane ( C H 4 ) is burned in the presence of oxygen ( O 2 ) to produce carbon dioxide ( C O 2 ) and water. Initially, the water is in gaseous form ( H 2 O ( g ) ), but as it cools down, it condenses into liquid water ( H 2 O ( l ) ). This process is crucial in understanding energy production and environmental impact, as it helps in calculating the net energy released and the amount of water produced in different states. Understanding such reactions is fundamental in designing efficient combustion engines and managing industrial processes.
The overall chemical equation obtained by combining the two given equations is C H 4 ( g ) + 2 O 2 ( g ) → C O 2 ( g ) + 2 H 2 O ( l ) , which corresponds to option A. After cancelling the common term 2 H 2 O ( g ) , we arrive at this final equation. This demonstrates how combustion reactions can lead to different forms of water depending on temperature and conditions.
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