B:
Although there are almost 100 elements in nature, only six of them compose 99% of our body’s mass— carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus.
Reaching 29,029 feet (8,848 meters) above sea level, Mount Everest is the highest mountain on Earth. Located in the Mahalangur section of the Himalayas, the mountain's summit straddles the border separating China and Nepal.
Or if you want a more literary description, try some devices to describe it i.e what's there, the atmosphere, the height/gradient etc.
2
2
3
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20
Is the answer for the question
Answer:
ΔH = -20kJ
Explanation:
The enthalpy of formation of a compound is defined as the change of enthalpy during the formation of 1 mole of the substance from its constituent elements. For H₂S(g) the reaction that describes this process is:
H₂(g) + S(g) → H₂S(g)
Using Hess's law, it is possible to sum the enthalpies of several reactions to obtain the change in enthalpy of a particular reaction thus:
<em>(1) </em>H₂S(g) + ³/₂O₂(g) → SO₂(g) + H₂O(g) ΔH = -519 kJ
<em>(2) </em>H₂(g) + ¹/₂O₂(g) → H₂O(g) ΔH = -242 kJ
<em>(3) </em>S(g) + O₂(g) → SO₂(g) ΔH = -297 kJ
The sum of -(1) + (2) + (3) gives:
<em>-(1) </em>SO₂(g) + H₂O(g) → H₂S(g) + ³/₂O₂(g) ΔH = +519 kJ
<em>(2) </em>H₂(g) + ¹/₂O₂(g) → H₂O(g) ΔH = -242 kJ
<em>(3) </em>S(g) + O₂(g) → SO₂(g) ΔH = -297 kJ
<em>-(1) + (2) + (3): </em><em>H₂(g) + S(g) → H₂S(g) </em>
<em>ΔH =</em> +519kJ - 242kJ - 297kJ = <em>-20 kJ</em>
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I hope it helps!
There are 2.06 x 10²⁴ atoms
<h3>Further explanation
</h3>
The mole is the number of particles (atoms, molecules, ions)contained in a substance
1 mol = 6.02.10²³ particles
Moles can also be determined from the amount of substance mass and its molar mass
