The question is incomplete, here is the complete question:

Xianming runs a titration and collects, dries, and weighs the
produced in the experiment. He reports a mass of 0.2989 g go
Based on this, calculate the concentration of
solution.
<u>Answer:</u> The concentration of barium hydroxide solution is 0.0013 moles.
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
Given mass of barium sulfate = 0.2989 g
Molar mass of barium sulfate = 47.87 g/mol
Putting values in above equation, we get:

The given chemical reaction follows:

By Stoichiometry of the reaction:
1 mole of barium sulfate is produced from 1 mole of barium hydroxide
So, 0.0013 moles of barium sulfate will be produced from =
of barium hydroxide
As, no volume of the container is given. So, the concentration will be calculated in moles only.
Hence, the concentration of barium hydroxide solution is 0.0013 moles.