Answer:

Explanation:
Hello,
In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

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Answer:
analytic chemistry
Explanation:
Analytical chemistry uses tests to discover ingredients in a substance. A pool worker tests the water to learn how much chlorine it contains. A nutritionist analyzes food to learn about the nutrients in it. Biochemistry is the study of chemistry in the body.
The physical properties of water is that it is clear, it has no taste. No odour. It freezes at 0 degrees Celsius and boils at 100 degrees Celsius. The different stages of water is liquid, solid and gas. It is liquid at normal state. Ice when solid and steam when it is a gas state.
It is essential for human life because majority of the human body is made out of water. The water in the body allows certain parts and organs to function properly. Without water humans are most like to become I’ll and even dehydrate causing major injuries. It is also essential for the brain to function
Answer: 1.99 x 10²² molecules H2
Explanation:First we will solve for the moles of H2 using Ideal gas law PV= nRT then derive for moles ( n ).
At STP, pressure is equal to 1 atm and Temperature is 273 K.
Convert volume in mL to L:
750 mL x 1 L / 1000 mL
= 0.75 mL
n = PV/ RT
= 1 atm ( 0.75 L ) / 0.0821 L.atm/ mole.K ( 273 K)
= 3.3x10-² moles H2
Convert moles of H2 to atoms using Avogadro's Number.
3.3x10-² moles H2/ 6.022x10²³ atoms H2 / 1 mole H2
= 1.99x10²² atoms H2