1) B) Kinetic energy is energy associated with the motion of an object.
2) B) Density equals mass divided by volume: 1.38 g/mL
3) C) There are 5 significant figures in 20.300
4) A) 80 is the atomic number for mercury on the periodic table.
5) E) The formula for copper (II) sulfate pentahydrate is CuSO4•5H2O
So in summary:
• Kinetic energy is the energy of a moving object due to its motion.
• Density is calculated by dividing an object's mass by its volume.
• Significant figures refer to the known precision of a measurement based on the digits reported.
• Atomic symbols represent elements on the periodic table.
• Chemical formulas use symbols of the elements to show the proportions of atoms in a compound.