Answer: 20.4752789138x x  10^23 atoms
To count how many atoms in moles you need to know Avogadro's number. Avogadro's number dictate that for every mole there is 6.022140857 × 10^23 molecule/atoms.
Then 3.4 moles of helium will be 3.4x 6.022140857 x  10^23 atoms= 20.4752789138x x  10^23 atoms
        
             
        
        
        
ANSWER - (1) are constantly moving (2) have volume (3) have intermolecular forces (4) undergo perfectly elastic collisions (5) have an average kinetic energy proportional to the ideal gas’s absolute temperature
        
             
        
        
        
Answer:
-0.912 m/s
Explanation:
When the package is thrown out, momentum is conserved. The total momentum after is the same as the total momentum before, which is 0, since the boat was initially at rest.

where  are the mass of the child, the boat and the package, respectively.
 are the mass of the child, the boat and the package, respectively.  are the velocity of the package and the boat after throwing.
 are the velocity of the package and the boat after throwing.



 
        
             
        
        
        
Answer:
22.26 years
, 15.585 light years  , 11.13 light years
Explanation:
a)

= 
= 22.26 years
b)
0.7*c*22.26 years
=15.585 light years  
c)
0.7*c*15.9
=11.13 light years