Answer : The fuel value and the fuel density of pentane is, 49.09 kJ/g and
respectively.
Explanation :
Fuel value : It is defined as the amount of energy released from the combustion of hydrocarbon fuels. The fuel value always in positive and in kilojoule per gram (kJ/g).
As we are given that:

Fuel value = 
Molar mass of pentane = 72 g/mol
Fuel value = 
Fuel value = 49.09 kJ/g
Now we have to calculate the fuel density of pentane.
Fuel density = Fuel value × Density
Fuel density = (49.09 kJ/g) × (0.626g/mL)
Fuel density = 30.73 kJ/mL = 
Thus, the fuel density of pentane is 
<span>Answer: B. Ionic solids have higher melting points than molecular solids.
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This is because the rest are false, as solids are able to melt, and do have melting points. Also, not all solids have the same melting points.
Answer:
Explanation:
Water vapor is when water molecules are present in the air, while steam is water heated to the point that it turns into gas. In simplified science, both are referred to as the gaseous state of water. Steam is usually white or translucent in nature, while water vapor can be clear or translucent.
Steam is simply, water vapor. Hence, the key difference between steam and vapor is that steam is the gaseous state of water whereas vapor is the gaseous state of any substance. Moreover, steam is typically invisible while the vapor of some substances is colorful.