Is this a valid equation?

NaNO3 + H2O = NaOH + HNO3

Why or why not?

No. The equals sign has no validity in chemical reactions.

I meant NaNO3 + H2O -> NaOH + HNO3

is this valid?

To determine if this is a valid equation, we need to balance it.

The equation you provided is not balanced because the number of atoms on both sides is not equal.

Let's go through the steps to balance the equation:

First, count the number of each atom on both sides of the equation:

On the left side (reactants):
Na: 1
N: 1
O: 3
H: 2

On the right side (products):
Na: 1
N: 1
O: 1
H: 1

Next, analyze each element and balance them one by one.

Let's start with sodium (Na). Both sides have 1 Na atom, so sodium is already balanced.

Next, let's look at nitrogen (N). Both sides also have 1 N atom, so it is balanced as well.

Now, let's focus on oxygen (O). On the left side, we have 3 O atoms (from NaNO3), but on the right side, we only have 1 O atom (from H2O). To balance the oxygen, we can add a coefficient in front of NaOH to match the number of O atoms.

Adding a coefficient of 3 in front of NaOH will give us:
NaNO3 + H2O = 3NaOH + HNO3

Finally, let's balance hydrogen (H). On the left side, we have 2 H atoms (from H2O), but on the right side, we only have 1 H atom (from HNO3). To balance hydrogen, we add another coefficient in front of HNO3.

Adding a coefficient of 2 in front of HNO3 will give us the balanced equation:
NaNO3 + H2O = 3NaOH + 2HNO3

So, the balanced equation is:
NaNO3 + H2O = 3NaOH + 2HNO3

Therefore, the given equation is not valid, but after balancing it, we obtained a valid and balanced equation.