Answer:
Gas is on top of oil
Explanation:
Gas is less dense ( smaller density ) than oil which is more dense. Since density is directly proportional to mass and inversely proportional to volume, gas will occupy a larger space than oil.
The larger space occupied is the space above the mixture of oil and gas, hence gas is above oil
The question is poor. Light doesn't refract on its way THROUGH anything. It refracts at the boundary BETWEEN two different media. The effect is greatest where the ratio of the speeds of light in the two media is greatest. On your list, that would be at the boundary between air or space and glass.
Ionic bonds have...
- High melting points
- Conductive properties
- Are good insulators
(Extra: Form crystal-like structures over just plain molecules!)