Could use some help with #3 and #4 please

The answer to your question is 3.- 0.67 l   4.- 0.72 atm

Explanation:

Data

Volume 1 = 2 l

Pressure 1 = 1 atm

Volume 2 = ?

Pressure 2 = 3 atm

Process

To solve this problem use Boyle's law.

        P1V1 = P2V2

-Solve for V2

        V2 = P1V1 / P2

-Substitution

        V2 = (1)(2) / 3

-Simplification

        V2 = 2/3

-Result

        V2 = 0.67 l

4.-

Volume 1 = 12 l

Pressure 1 = 0.9 atm

Volume 2 = 15 l

Pressure 2 = ?

Process

To solve this problem use Boyle's law

           P1V1 = P2V2

-Solve for P2

           P2 = P1V1 / V2

-Substitution

           P2 = (0.9 x 12) / 15

-Simplification

           P2 = 10.8 / 15

-Result

           P2 = 0.72 atm

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error