Aflat plug 30 mm thick having an area of 4.0 × 10–4m2 and made of vulcanized rubber is used for closing an opening in a container. the gas co2 at 25°c and 2.0 atm pressure is inside the container. calculate the total leakage or diffusion of co2 through the plug to the outside in kg mol co2/s at steady state. assume that the partial pressure of co2 outside is zero. from barrer (b1), the solubility of the co2 gas is 0.90 m3 gas (at stp of 0°c and 1 atm) per m3 rubber per atm pressure of co2. the diffusivity is 0.11 × 10–9m2/s.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

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.