Weight is mass x gravity, so you'd multiply the mass of the astronaut by the gravitational pull.
We can use the equation of state for an ideal gas to answer the question:

or, by rewriting it,

where p is the gas pressure, V its volume, T its temperature, n the number of moles of the gas and R the gas constant.
When the gas is sprayed from the can into the room, its volume V has increased, while n (the number of moles of the gas) stayed the same. Since R is a constant and the temperature T also stayed constant, if we look at the formula we see that the numerator didn't change, while the denominator (V) has increased, so the pressure of the gas has decreased.
C. in a covalent bond, they are shared by two atoms, while in an ionic bond, they are transferred
Answer:
By the law of conservation of mechanical energy, in the absence of any drag, when the rock falls towards the ground, the potential energy gets converted to kinetic energy. Once the rock hits the ground, it does not move. This is because, the energy is dissipated as sound or heat (to the environment). The total energy remains conserved. Only the form of energy changes.