Acylinder with a movable piston contains 2.00 g of helium, he, at room temperature. more helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. how many grams of helium were added to the cylinder if the volume was changed from 2.00 l to 4.50 l ? (the temperature was held constant.)

2.5 grams

Explanation:

To calculate the moles, we use the equation:

Avogadro's Law: This law states that volume is directly proportional to the number of moles of the gas at constant pressure and temperature.

  (At constant temperature and pressure)  

where,

= initial volume of gas = 2.00 L

= final volume of gas = 4.50 L

= initial number of moles = 0.5 moles

= final number of moles = ?

Now put all the given values in the above equation, we get the final pressure of gas.

Thus moles of helium added to the cylinder = (1.125-0.5)= 0.625 moles

Mass of helium added =

2.5 grams of helium were added to the cylinder if the volume was changed from 2.00 L to 4.50 L.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.

answerlinnaeus;