D. photons it contains light but with zero mass
Density is defined as mass/volume (or m/v).
So,
(126.0 g)/(12.5 cm^3)= 10.08 g/cm^3
If your teacher requires correct significant figures, the answer is 10.1 g/cm^3.
If not, the first answer is fine.
Radiant energy to thermal energy
Answer:

Explanation:
Moles of SO₃ = 0.760 mol
Volume = 1.50 L


[SO₃] = 0.5067 M
Considering the ICE table for the equilibrium as:

Given:
Equilibrium concentration of O₂ = 0.130 mol
Volume = 1.50 L


[O₂] = x = 0.0867 M
[SO₂] = 2x = 0.1733 M
[SO₃] = 0.5067-2x = 0.3334 M
The expression for the equilibrium constant is:

Answer:
The metals that would be able to reduce copper ions in solution would be hydrogen, lead, tin, nickel, iron, zinc, aluminum, magnesium, sodium, calcium, potassium, silver, gold, copper and lithium 5.
Explanation: