· The cylinder of a bicycle pump has a volume of 1.25 L at standard pressure (1 atm). A bicycle tire is to be inflated to a total pressure of 4.75 atm. To reach this pressure, the
confined
gas in a bicycle pump is compressed to a smaller volume. At what volume does the
confined gas exert a pressure of 4.75 atm?

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.