Question

the mass of a beaker was measured to be 125.445 g. a buret was used to deliver 25.00 ml of water to the beaker and the mass of the beaker and the water was measured again. the mass measured was 150.451 g. after pouring the water in the beaker into a new container, the mass of the first beaker was measured to be 125.817 g. what mass of water remained in the beaker after pouring the water into the new container? report your answer to the correct number of significant figures.

Explanation:

Step1: Identify the initial mass of the beaker

The initial mass of the beaker is \( 125.445 \, \text{g} \).

Step2: Identify the mass of the beaker after pouring out water

The mass of the beaker after pouring out water is \( 125.817 \, \text{g} \). Wait, no—wait, actually, to find the mass of water remaining, we need to find the difference between the mass of the beaker after pouring out water and the initial mass of the beaker? Wait, no, let's re-examine. Wait, the initial mass of the beaker is \( 125.445 \, \text{g} \). After pouring the water into a new container, the mass of the beaker is \( 125.817 \, \text{g} \)? Wait, that can't be—wait, no, maybe I misread. Wait, the beaker initially has mass \( 125.445 \, \text{g} \). Then we add water, measure the beaker + water as \( 150.451 \, \text{g} \). Then we pour the water out, and measure the beaker again as \( 125.817 \, \text{g} \). So the mass of water remaining is the mass of the beaker after pouring minus the initial mass of the beaker.

So, mass of water remaining = mass of beaker after pouring - initial mass of beaker.

So, \( 125.817 \, \text{g} - 125.445 \, \text{g} \).

Step3: Calculate the difference

\( 125.817 - 125.445 = 0.372 \, \text{g} \).

Wait, but let's check the significant figures. The initial mass is \( 125.445 \, \text{g} \) (six significant figures), the mass after pouring is \( 125.817 \, \text{g} \) (six significant figures). The subtraction gives \( 0.372 \, \text{g} \), which has three significant figures. Let's verify:

Initial beaker mass: \( 125.445 \, \text{g} \)

Beaker after pouring: \( 125.817 \, \text{g} \)

Difference: \( 125.817 - 125.445 = 0.372 \, \text{g} \).

Yes, that makes sense. The water remaining is the mass of the beaker after pouring minus the initial beaker mass, because the initial beaker was empty (or had no water initially, then we added water, then poured most out, and the remaining water is what's left in the beaker, so the beaker's mass plus remaining water is \( 125.817 \, \text{g} \), and the beaker's mass alone is \( 125.445 \, \text{g} \), so the difference is the remaining water.

Answer:

\( 0.372 \)