Answer:
Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.
Answer : The value of new volume is, 50.0 mL
Explanation :
Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

or,

where,
= initial pressure at STP = 1 atm
= final pressure = 4.00 atm
= initial volume at STP = 200.0 mL
= final volume = ?
Now put all the given values in the above equation, we get:


Therefore, the value of new volume is, 50.0 mL
Tropic levels have most energy
Answer:
A catalyst is a chemical substance that alters the rate of chemical reaction not consumed by the reaction. Hence, a catalyst can be recovered chen unchanged at the ends of chemical reaction. Catalyst can be divided into two typ the basis whether it speeds up or slowdowns the rate of chemical reaction. The positive catalyst and negative catalyst.
46 is the answer. because if you add 26 and 20 that is the mass