Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.
We have the following equation representing the half-life decay:

A is the resulting amount after t time
Ao is the initial amount = 50 mg
t= Elapsed time
t half is the half-life of the substance = 14.3 days
We replace the know values into the equation to have an exponential decay function for a 50mg sample

That would be the answer for a)
To know the P-32 remaining after 84 days we have to replace this value in the equation:

So, after 84 days the P-32 remaining will be 0.85 mg
Given the speed, you will travel 195km in 3 hours.
65 x 3 = 195
Mass of Ni = 0.015 mol Ni × (58.693 g Ni/1 mol Ni) = 0.88 g Ni
Answer
Atomic number or proton number tells us the number of protons found in the nucleus of every atom of that element
Explanation:
The liquid particles would have moved randomly because of the increase in thermal energy. They would move randomly and would be floating in the bottle moving randomly. The liquid would turn into gas form. Meaning that you would have water particles floating in the bottle moving randomly.