Iron-59 is a beta emitter with a half-life of 44.5 days. if a sample initially contains 180 mg of iron-59, how much iron-59 is left in the sample after 267 days?

2.79 mg iron-59 is left in the sample after 267 days.

Explanation:

Given that:

Half life = 44.5 days

Where, k is rate constant

So,  

The rate constant, k = 0.0156 days⁻¹

Using integrated rate law for first order kinetics as:

Where,  

is the concentration at time t

is the initial concentration  = 180 mg

Time = 267 days

So,  

2.79 mg iron-59 is left in the sample after 267 days.

the ratio of the conjugate base to the acid required to attain the desired ph.

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.