If a sample of C-14 initially contains 1.2 mmol of C-14, how many millimoles will be left after 2285 years?

The amount of millimoles left after 2285 years is 0.910 millimoles

Explanation:

The half life of  a substance is the time require for a radioactive decaying substance to have decayed int half of its initial quantity. Half life is used to different types or forms of decay such as in nuclear physics, to describe the time of decay of unstable atoms and in medicine to define a drugs half-life

To  solve this, we are required to state the hlf life of C-14 which is 5,730 years

Hence the formula for calculating half life is  

∴ = 0.910 millimoles will be left after 2285 years

1. they vary with a higher number because boiling is way hotter than melting

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.