Stephanie is incorrect. Since fossil fuels form in the absence of oxygen, if oxygen is present, they cannot form.
(sample answer:)
The Earth, Mars or Jupiter should be denser than the Sun. Density is defined by mass and volume — components of object or matter. Although the sun is huge, it’s component is made up of mostly gas (hydrogen and helium). While Earth, though smaller than the Sun, contains heavier elements such as iron, sulfur, rocks, sediments, granite, basalt and water. Mars (composed of rocks and nutrients) and Jupiter (contains gases and compounds) as well are denser when compared to the Sun’s density. Referencing to our basic understanding of matter: solid and liquid should be heavier than gas.
Answer:
The Avogadro's number is 
Explanation:
From the question we are told that
The edge length is 
The density of the metal is 
The molar mass of Ba is 
Generally the volume of a unit cell is
substituting value
![V = [5.02 *10^{-10}]^3](https://tex.z-dn.net/?f=V%20%3D%20%20%5B5.02%20%2A10%5E%7B-10%7D%5D%5E3)
From the question we are told that 68% of the unit cell is occupied by Ba atoms and that the structure is a metal which implies that the crystalline structure will be (BCC),
The volume of barium atom is
substituting value
The Molar mass of barium is mathematically represented as
Where 
is the Avogadro's number
So
substituting value
The answer is C.
The vast difference in electronegativity of the oxygen and hydrogen in water, the O-H bond is polar.
Reaction of sodium with water
Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic. During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour. The reaction is slower than that of potassium (immediately below sodium in the periodic table), but faster than that of lithium (immediately above sodium in the periodic table).
2Na(s) + 2H2O → 2NaOH(aq) + H2(g)
