In the J-tube above, Y and X are on the same horizontal level and 30cm3 of air is trapped above Y when the atmospheric pressure is 75cm Hg, calculate the vo...

The J-tube is a device used to measure the pressure of gases. In this case, we have 30cm3 of air trapped above Y when the atmospheric pressure is 75cm Hg. When 15cm Hg is added to the limb above X, the pressure on both sides of the J-tube will be equalized, and the volume of air trapped above Y will change. To find the new volume of air trapped above Y, we can use Boyle's law, which states that the pressure of a gas is inversely proportional to its volume when the temperature is constant. Therefore, we can set up the equation: P1 x V1 = P2 x V2 where P1 and V1 are the initial pressure and volume of the air trapped above Y, and P2 and V2 are the final pressure and volume of the air trapped above Y. Plugging in the values given, we get: 75 cm Hg x 30 cm3 = (75 cm Hg + 15 cm Hg) x V2 Simplifying the equation: V2 = (75 cm Hg x 30 cm3) / (75 cm Hg + 15 cm Hg) V2 = (75 cm Hg x 30 cm3) / 90 cm Hg V2 = 25 cm3 Therefore, the volume of air trapped above Y when 15cm Hg is poured into the limb above X is 25 cm3. Answer: 25 cm3.