There are 3 known isotopes of Hydrogen and 3 stable isotopes of oxygen. How many types of water molecules would these produce?

Is it 3 ?

No, it is not 3. To determine the number of types of water molecules that can be formed using different isotopes of hydrogen (H) and oxygen (O), we need to consider the combination possibilities.

First, let's list the isotopes of hydrogen:
1. Protium (H-1) - most common and stable isotope
2. Deuterium (H-2) - heavier isotope with one neutron
3. Tritium (H-3) - radioactive and very rare isotope with two neutrons

Next, let's list the stable isotopes of oxygen:
1. Oxygen-16 (O-16) - the most abundant and stable isotope
2. Oxygen-17 (O-17) - stable isotope with one extra neutron
3. Oxygen-18 (O-18) - stable isotope with two extra neutrons

For a water molecule (H2O), we need two hydrogen atoms and one oxygen atom.

Now, let's consider the possible combinations of isotopes for the water molecules:
1. Two protium atoms (H-1 + H-1) and one oxygen-16 atom (O-16) would form the most common type of water molecule, known as "light water."
2. Combining one deuterium atom (H-2) with one protium atom (H-1) and one oxygen-16 atom (O-16) would form a water molecule known as "semi-heavy water."
3. Combining two deuterium atoms (H-2 + H-2) with one oxygen-16 atom (O-16) would form a water molecule known as "heavy water."
4. Combining one tritium atom (H-3) with two protium atoms (H-1 + H-1) and one oxygen-16 atom (O-16) would form a water molecule known as "tritiated water."

So, considering the different combinations of isotopes, the answer is that there can be four different types of water molecules: light water, semi-heavy water, heavy water, and tritiated water.