What is the balanced equation of Cr2O7(-2) + Cl(-) → Cr(3+) + Cl2?
To balance the given chemical equation:
Step 1: Write down the unbalanced equation:
Cr2O7(-2) + Cl(-) → Cr(3+) + Cl2
Step 2: Balance the atoms other than hydrogen and oxygen. In this equation, we will balance the chromium and chlorine atoms first.
Cr2O7(-2) + 14Cl(-) → 2Cr(3+) + 7Cl2
Step 3: Balance the oxygen atoms. Since there are 7 oxygen atoms in the dichromate ion (Cr2O7(-2)), we will add 7 water (H2O) molecules to the product side.
Cr2O7(-2) + 14Cl(-) → 2Cr(3+) + 7Cl2 + 7H2O
Now, we have balanced the equation, with equal numbers of atoms on both sides. The balanced equation is:
Cr2O7(-2) + 14Cl(-) → 2Cr(3+) + 7Cl2 + 7H2O
To balance the equation Cr2O7(-2) + Cl(-) → Cr(3+) + Cl2, you need to ensure that there is the same number of atoms of each element on both sides of the equation.
Let's start by examining each element individually.
On the reactant side, we have:
- Chromium (Cr): There are 2 chromium atoms in Cr2O7(-2).
- Oxygen (O): There are 7 oxygen atoms in Cr2O7(-2).
- Chlorine (Cl): There is 1 chlorine atom in Cl(-).
On the product side, we have:
- Chromium (Cr): There is 1 chromium atom in Cr(3+).
- Oxygen (O): There are no oxygen atoms on the product side.
- Chlorine (Cl): There are 2 chlorine atoms in Cl2.
We can start by balancing the chromium atoms. Currently, there are 2 chromium atoms on the reactant side and only 1 on the product side. To balance this, we need to multiply the chromium on the product side by 2.
The equation now becomes: Cr2O7(-2) + Cl(-) → 2Cr(3+) + Cl2.
Next, let's balance the chlorine atoms. Currently, there is 1 chlorine atom on the reactant side and 2 on the product side. To balance this, we need to multiply the Cl(-) on the reactant side by 2.
The equation now becomes: Cr2O7(-2) + 2Cl(-) → 2Cr(3+) + Cl2.
Now, let's balance the oxygen atoms. There are 7 oxygen atoms on the reactant side and none on the product side. To balance this, we need to add 7 waters (H2O) to the product side.
The equation now becomes: Cr2O7(-2) + 2Cl(-) → 2Cr(3+) + Cl2 + 7H2O.
Finally, double-checking the equation, we have:
2Cr2O7(-2) + 14Cl(-) → 12Cr(3+) + 7Cl2 + 7H2O.
So, the balanced equation is 2Cr2O7(-2) + 14Cl(-) → 12Cr(3+) + 7Cl2 + 7H2O.
well, each Cl- loses one electron, and each Cr+6 ion gains three electrons to go to Cr+3, so we need three Cl- for each Cr+6
Cr2O7-2 + 6 Cl-1 >> 2Cr+3 + 3Cl2
check my thinking.