You're asking for the mass of the water in a beaker that weighs 100.00g.

Here's the problem:

* We don't know the mass of the empty beaker. To find the mass of just the water, you need to know the mass of the empty beaker and subtract it from the total mass (100.00g).

Here's how to do it if you knew the mass of the empty beaker:

1. Mass of beaker (empty): Let's say the empty beaker weighs 50.00g.

2. Mass of beaker + water: 100.00g

3. Mass of water: 100.00g - 50.00g = 50.00g

Please provide the mass of the empty beaker, and I can calculate the mass of the water.