A
carbon
atom
has
a
relative
atomic
mass
of
12.7.
55%
of
the
carbon
atom
has
a
mass
number
of
12.5,
whilst
the
remaining
45%
has
a
mass
number
which
is
not
known.
Calculate
the
mass
number
of
the
carbon
isotope
which
is
45%
of
the
Carbon
12.7
atom.
Give
your
answer
to
2
decimal
places
if
needed
To calculate the mass number of the carbon isotope that is 45% of the Carbon 12.7 atom, we need to take 45% of the total relative atomic mass and subtract it from the mass number of 12.5.
45% of 12.7 is:
(45/100) * 12.7 = 5.715
To find the mass number of the carbon isotope:
12.5 - 5.715 = 6.785
Therefore, the mass number of the carbon isotope that is 45% of the Carbon 12.7 atom is 6.785.