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
MgF2 is <span>Magnesium fluoride
hope this helps!</span>
The density of the block will be "7.11 gm/cm³". A further explanation is provided below.
Given values are:
Density of iron,
Mass of block of metal,
Volume of block,
By using the formula,
→ 
then,
→ The density of block will be:
= 
= 
= 
Learn more:
brainly.com/question/10804879
(1) Copper:
Copper has the atomic number : 29
Cu2+ means that it lost 2 electrons, therefore, the total number of electrons is 29-2 = 27 electrons.
The electronic configuration is:
1s2 2s2 2p6 3s2 3p6 3d9
(2) Silver:
Silver has atomic number : 47
Ag + means that it lost one electron, therefore, the total number of electrons is 47-1 = 46 electrons
The electronic configuration is:
<span>1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10</span>
