Explanation:
Carbon exists in several isotopes. ... Carbon has the atomic number of 6 which means that all isotopes have the same proton number. However, the number of neutrons is different, thus giving different mass numbers. Carbon-12 has 6 neutrons, carbon-13 has 7 neutrons, and carbon-14 contains 8 neutrons.
B
A definite chemical composition means that all occurrences of that mineral have a chemical composition that varies within a specific limited range and the atoms that make up the mineral must occur in specific ratios.
Mass % of NaCl = 0.9 % (m/v)
Density of 0.9 % NaCl is about 1.0 g/mL
Volume of NaCl in mL :

= 11.25 mL NaCl