How can oxidation numbers be used to balance chemical equations?

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In summary, the conversation is about balancing a chemical equation by either algebraic or oxidation methods. The person is having trouble balancing the equation and asks for help. The other person suggests typing out the equation instead of using pictures and provides a hint to solve it using oxidation numbers.
  • #1
Witcher
15
3
Homework Statement
I have been on letter A problem for hours now and can’t seem to balance the equation.
Relevant Equations
It is a combustion reaction i think because both sides have oxygen and hydrogen
I attached my attempt and the question from the book, as you can see i kept failing because my hydrogens wouldn't balance and neither would my oxygens.
 

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  • #2
I can't read the pictures: they are rotated 90 degrees to the right. Please put hem upright, or better: type them out.
 
  • #3
A is not a combustion reaction though.
 
  • #4
You can do example (a) algebraically. Write the balanced equation as $$aN_2H_4+bH_2O_2=cHNO_3+dH_2O$$Based on this, what is the balance on nitrogen atoms? What is the balance on H atoms? What is the balance on O atoms? Solve these 3 equations in 4 unknowns for b, c, and d in terms of a. What do you get?
 
  • #5
This one may be simpler if you go by oxidation numbers, noting that total oxidation number is conserved.
Hint: oxygen goes from -1 to -2 (in both products); nitrogen goes from -2 to +5; H doesn't change.
 

1. What is a chemical equation and why is it important to balance it?

A chemical equation is a symbolic representation of a chemical reaction. It shows the reactants on the left side and the products on the right side, separated by an arrow. It is important to balance a chemical equation because it follows the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Balancing the equation ensures that the same number of atoms of each element are present on both sides.

2. How do you balance a chemical equation?

To balance a chemical equation, you need to ensure that the number of atoms of each element on the reactant side is equal to the number of atoms of that element on the product side. This can be achieved by adjusting the coefficients (numbers in front of each compound) until the number of atoms on both sides are balanced. It is important to note that you should never change the subscripts of a compound, as this would change the identity of the substance.

3. Can you give an example of balancing a chemical equation?

Sure, let's take the combustion of methane gas (CH4) in the presence of oxygen gas (O2) to form carbon dioxide (CO2) and water (H2O). The unbalanced equation is: CH4 + O2 → CO2 + H2O. To balance this equation, we need to add a coefficient of 2 in front of CH4 and a coefficient of 2 in front of H2O, giving us the balanced equation: 2CH4 + 2O2 → 2CO2 + 2H2O.

4. Are there any rules or guidelines to follow when balancing a chemical equation?

Yes, there are a few guidelines that can help make balancing chemical equations easier. Firstly, start by balancing elements that appear only once on each side of the equation. Next, balance elements that appear in more than one compound on each side. Finally, balance the elements that appear in compounds with multiple elements, such as polyatomic ions. It can also be helpful to check your work by counting the number of atoms of each element on both sides of the equation.

5. What are the consequences of an unbalanced chemical equation?

If a chemical equation is unbalanced, it means that the number of atoms of each element on the reactant side does not equal the number of atoms on the product side. This can lead to incorrect predictions about the products of the reaction, as well as violate the law of conservation of mass. In addition, an unbalanced equation can make it difficult to accurately measure the amounts of reactants needed for the reaction to occur.

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