When you balance equations, do you treat polyatomic ions as one unit or treat the different elements in the ion separately? Because if you treat them as one unit, then what if the elements get separated in the products side of the equation?
You have to make sure that each ELEMENT has the same number of atoms on each side of the equation. so treat polyatomics like they are separate elements. if you have say, SO4 on one side, you have to make sure that there are 4 oxygen atoms and one sulfur atom on the other side too, regardless of if they are together or not. does that help?
Let me expand a little on the very good answer Anne gave. I do it BOTH ways. IF the polyatomic ion stays intact, it is much easier and quicker to check everything as units. However, if they are separated, as you note in some instances, you are left with no choice but to balance individual elements as Anne has indicated. .
When balancing equations that involve polyatomic ions, you generally treat the entire ion as a single unit. This means that you would not separate the elements within the ion when balancing the equation.
For example, let's consider the equation:
NaOH + HCl -> NaCl + H2O
In this equation, you have the polyatomic ion OH^- (hydroxide ion) on the left side. When balancing, you would treat the OH^- ion as a whole and not break it down into separate hydrogen and oxygen atoms.
Similarly, on the product side, the NaCl that is formed would have the Na+ and Cl^- ions treated as one unit.
It's important to note that even if the elements within the polyatomic ion appear separated on the product side, you would still treat the whole ion as a single unit when balancing the equation. The coefficients can be adjusted to make sure that both sides of the equation have the same number of atoms of each element.
When balancing chemical equations, it is usually best to consider polyatomic ions as one unit rather than breaking them into individual elements. Treating them as a single unit helps to maintain the overall charge balance in the equation and simplifies the balancing process.
In a chemical equation, polyatomic ions can appear on both the reactant and product sides. If the elements within the polyatomic ion get separated in the products, it means that the ion has undergone a chemical reaction and its composition has changed. In this case, you would need to balance the equation accordingly to maintain the conservation of mass and charge.
Here's an example to illustrate this:
Let's consider the reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl) to form sodium chloride (NaCl) and water (H2O).
The balanced equation would be:
NaOH + HCl -> NaCl + H2O
In this equation, the sodium ion (Na⁺) and the hydroxide ion (OH⁻) combine to form sodium chloride, while the hydrogen ion (H⁺) from the hydrochloric acid combines with the hydroxide ion to form water.
As you can see, the polyatomic ions (OH⁻ and Cl⁻) are treated as one unit throughout the balancing process, meaning you don't separate the elements within them. However, their composition changes when water is formed.
So, to summarize, when balancing equations, treat polyatomic ions as one unit unless their composition changes during the reaction. In that case, adjust the equation accordingly to maintain mass and charge balance.