Answer:
Option C. Metal C.
Explanation:
To know which option is correct, we'll begin by calculating the density of each metal.
The density of a substance is simply defined as the mass of the substance per unit volume of substance. It can be expressed mathematically as:
Density = mass /volume.
Now, we shall determine the density of each metal as follow:
Metal A:
Volume = 12.5 cm³
Mass = 122 g
Density =?
Density = mass /volume
Density = 122/12.5
Density = 9.76 g/cm³
Metal B:
Volume = 14.2 cm³
Mass = 132 g
Density =?
Density = mass /volume
Density = 132/14.2
Density = 9.30 g/cm³
Metal C:
Volume = 18.1 cm³
Mass = 129 g
Density =?
Density = mass /volume
Density = 129/18.1
Density = 7.13 g/cm³
Metal D:
Volume = 12.7 cm³
Mass = 126 g
Density =?
Density = mass /volume
Density = 126/12.7
Density = 9.92 g/cm³
Summary:
Metal >>>>>>>> Density
A >>>>>>>>>>>> 9.76 g/cm³
B >>>>>>>>>>>> 9.30 g/cm³
C >>>>>>>>>>>> 7.13 g/cm³
D >>>>>>>>>>>> 9.92 g/cm³
From the above calculations, metal C has the lowest density.
where N0 is the initial quantity, Nt is the remaining quantity after time t, t1/2 is the half-time. So work out the equation, t1/2 = t (-ln2)/ln(Nt/N0) = 11.5*(-ln2)/ln(12.5/100) = 3.83 days
