Answer:
Isotopes of an element have same number of protons but different number of neutrons. Which means isotopes of an element have same atomic number but different mass number.
The chemical property of an element is determined by the number of electrons. And as all the isotopes have same number of electrons, they have same chemical properties.
Thus as isotopes of an element have same atomic number , they have same number of electrons and protons. As they have different mass number, the number of neutrons will be different. Hydrogen has three isotopes , 
, 
and 
. Thus has no neutron.
Acceleration is defined as velocity per unit time.
Here, a=acceleartion,
v=velocity=36 m/s
t=time=12 s
A car at rest ends accelerates for 12 seconds. After this time the car is going 36 m/s. So acceleration that is a=3 ms⁻².
Answer:
Conduction is the transfer of thermal energy through direct contact. Convection is the transfer of thermal energy through the movement of a liquid or gas. Radiation is the transfer of thermal energy through thermal emission.
One thing that does not change is the chemical composition of water, which is still H2O. And maybe mass, if all of the particles remain inside the beaker, which was never mentioned in the question so I am not sure.
To find average atomic mass you multiply the mass of each isotope by its percentage, and then add the values up.
35 * 0.90 + 37 * 0.08 + 38 * 0.02 = 35.22
Average atomic mass closest to 35.22 amu.
