Question

A

carbon
atom
has
a
relative
atomic
mass
of
12.6.
60%
of
the
carbon
atom
has
a
mass
number
of
12.1,
30%
of
the
carbon
atoms
have
a
mass
number
of
13.8,
whilst
the
remaining
10%
have
a
mass
number
which
is
not
known.
Calculate
the
mass
number
of
the
carbon
isotope
which
is
10%
of
the
Carbon
12.6
atom.
Give
your
answer
to
1 decimal place, if needed.

Answer 1

To calculate the mass number of the carbon isotope that constitutes 10% of the carbon atom with a relative atomic mass of 12.6, we need to consider the known percentages of carbon atoms with different mass numbers.

Given:

- 60% of carbon atoms have a mass number of 12.1
- 30% of carbon atoms have a mass number of 13.8
- The remaining 10% have a mass number that is not known

Let's calculate the mass number of the carbon isotope that constitutes 10% of the carbon atom:

Total percentage accounted for = 60% + 30% = 90%

The remaining 10% is attributed to the unknown mass number.

To find the mass number of the carbon isotope that constitutes 10% of the total, we can set up the following equation:

(10% / 90%) * x = 10%

Here, 'x' represents the mass number of the carbon isotope.

Simplifying the equation:

x / 90 = 1 / 10

Cross-multiplying:

10x = 90

Dividing both sides by 10:

x = 9

Therefore, the mass number of the carbon isotope that constitutes 10% of the carbon atom is 9.