Idk if it's correct but I guess it's calcite (c)
A chemical reagent that is used in this experiment is silver nitrate (AgNO3). It is used to distinguish calcium chloride and calcium carbonate. when this reagent is used, silver from silver nitrate reacts with Chloride to calcium chloride and forms silver chloride, making a precipitates of white color.
570/8.5=67.0 58... you only have to take the natural part, si the answer is 67 students
If i had to answer i would choose a hope this helps
So half life is the time taken for a sample to decay to half its original mass, its a constant and applies to any original mass, it could be 5g or 1kg, it will take the same amount of time for the original mass to half. In this case the half life is 3 days.
After 3 days the sample will be at half its original mass, now 50g.
Now we can treat the 50g as if its a new sample. After another 3 days (6 days in total) there will be half of 50g left, = 25g.
