why is (NH4)2Cr2O7 >> N2 + Cr2O3 + 4 H2O balanced like this.
I'm not sure what you mean by "why is....." I suppose the simple answer is "because those are the numbers it takes to balance the equation." What you have is a decomposition reaction and the products on the right are the products of the reaction.
To balance the chemical equation (NH4)2Cr2O7 → N2 + Cr2O3 + 4 H2O, we need to ensure that the number of atoms of each element is the same on both sides of the equation.
Let's start by counting the number of atoms for each element on the left and right side of the equation:
Left Side (Reactants):
- 2 atoms of nitrogen (N)
- 14 atoms of hydrogen (H)
- 2 atoms of chromium (Cr)
- 7 atoms of oxygen (O)
Right Side (Products):
- 2 atoms of nitrogen (N)
- 6 atoms of hydrogen (H)
- 2 atoms of chromium (Cr)
- 11 atoms of oxygen (O)
The next step is to balance the equation by adjusting the coefficients in front of each compound. Here's the step-by-step process:
1. Start with the element that appears in the fewest compounds on either side of the equation, in this case, nitrogen (N). Balance the number of N atoms on both sides of the equation by changing the coefficient of N2:
(NH4)2Cr2O7 → 2 N2 + Cr2O3 + 4 H2O
2. Next, balance the number of hydrogen (H) atoms. Adjust the coefficient of H2O:
(NH4)2Cr2O7 → 2 N2 + Cr2O3 + 4 H2O
3. Now, let's balance the number of chromium (Cr) atoms. Modify the coefficient of Cr2O3:
(NH4)2Cr2O7 → 2 N2 + 2 Cr2O3 + 4 H2O
4. Finally, balance the number of oxygen (O) atoms. Adjust the coefficient of (NH4)2Cr2O7:
2 (NH4)2Cr2O7 → 2 N2 + 2 Cr2O3 + 4 H2O
Now, the equation is balanced, with the same number of each atom on both sides.