The diameter of a certain atomic nucleus is 2.50 x 10-3 pm and its mass is 2.30 x 10-23 g.?

Question

What is the density of the nucleus in grams per centimeter cubed ? Assume the nucleus is a sphere with a volume equal to 4/3 P r 3

Enter a numeric answer only, no units. Use at least the correct number of significant figures.

Answer 1

r = D/2 = 1.25 x 10^-3 pm = 1.25 x 10^-15 m = 1.25 x 10^-13 cm.
So V = 4/3 π r^3 = 4/3 π (1.25 x 10^-13)^3 = 8.181 x 10^-39 cm^3.
Density is ρ = m/V = 2.30 x 10^-23 / 8.181 x 10^-39 = 2.81 x 10^15 g/cm^3. Note that since there are 3sf in both items of data we have 3sf in the result.

Answer 2

For this you just replace x with -10 So in this case it will be, -10^2-4 Next line is then a simple calculation,-10^2 is -10 x -10 = 100 as two minuses give you a plus and then you subtract 4 from the 100 giving you a final answer of 96.