A. The Average Ecological footprint will need to decrease . 6-11-18
<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
According to the Law of Conservation of Energy, energy is neither created nor destroyed. It is an entity that's always existing in the environment. It takes different forms of energy. Among the choices, the best answer would be letter B. Chemical energy. The chemical energy originates from the energy within the muscles that are dormant. Once used, this chemical energy is transformed into mechanical energy by the action of pushing his foot on the ground.
Answer:
15.71g
Explanation:
The general combustion equation for all hydrocarbons is
CxHy + (x+y/4) O2 = xCO2 + (y/2) H2O
For octane, C8H18 :
C8H18 + ( 8 + 18/4 ) O2 = 8CO2 + 9H2O
C8H18 + 50/4 O2 = 8CO2 + 9H2O
C8H18 + 25/2 O2 = 8CO2 + 9H2O
2C8H18 + 25 O2 = 16 CO2 + 18H2O (balanced)
From the balanced equation,
2 x 22.4 L of octane produced 16 [ 12 + (16 x 2)] of carbon dioxide
That is,
44.8 L of octane produced 704g of carbon dioxide
So, 1L of octane will produce 1 L x 704g/44.8 L = 15.71g of carbon dioxide
Therefore, 15.71g of carbon dioxide will be produced by the complete combustion of 1 L of octane.