The equation to calculate Density is Mass / Volume. You are given that the density is 5.45 and the mass is 65; 5.45 = 65 / v. So v = 65 / 5.45; v = 11.93 mL (or if you want your answer to consider significant figures, v = 12 mL).
You can find an element's amount of energy level by determining their place on the periodic table. An element's amount of energy levels are represented by which period/ row they are in. For example, Calcium has 4 energy levels. I know this because it is in the fourth period on the table.
Hope this helps!
Development of carbonation
Answer:
3000 kJ/kg
Explanation:
The calorific value of a substance is the amount of heat produced per unit mass by the combustion of the substance.
It is given by:

where
Q is the amount of heat released
m is the mass of the fuel
In this problem, we have:
m = 60 kg is the mass of fuel
is the amount of heat released
Therefore, the calorific value of the fuel is:

Answer:
The pigment that causes leaves to be green is chlorophyll. ... As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall. In fall, plants break down and reabsorb chlorophyll, letting the colors of other pigments show through.