Answer:
THE ENTHALPY OF REACTION IN KJ/MOL OF CH4 IS 7.07 KJ/MOL.
Explanation:
Mass of H2 = 3 g
Molar mass of H2 = 2 g/mol
Heat released = 53.3 kJ
Equation of the reaction:
C(s) + 2H2(g) -------> CH4(g)
First:
Calculate the number of moles of H2 that was used:
Number of moles = mass / molar mass
Number of moles = 3g / 2g
Number of moles = 1.5 moles
So therefore, when 53.3 kJ of heat was released from the reaction, 1.5 moles of hydrogen was used.
From the equation of the reaction, one mole of carbon reacts with two moles of hydrogen to form one mole of methane.
For 3 g of hydrogen, 1.5 mole of hydrogen is involved.
It means:
1.5 moles of hydrogen reacts with 0.75 moles of carbon and produces 0.75 moles of methane. This is so because the reaction occurs in 1: 2: 1 in respect to carbon, hydrogen and methane respectively.
So we can say that the production of 0.75 mole of methane will evolve 53.3 kJ of heat.
0.75 mole of methane releases 53.3 kJ of heat.
1 mole of methane will release ( 53.3 kJ * 1 / 0.75 )
= 71.0666 kJ of heat
In conclusion, the enthalpy of the reaction in kJ/ mole of CH4 is 71.07 kJ/mol.
Biodiversity has a fundamental value to humans because we are so dependent on it for our cultural, economic, and environmental well-being. Some argue that it is our moral responsibility to preserve the Earth’s incredible diversity for the next generation. Others simply like knowing that nature’s great diversity exists and that the opportunity to utilize it later, if need be, is secure. Scientists value biodiversity because it offers clues about natural systems that we are still trying to understand. Arguably, the greatest value to humans, however, comes from the ?ecosystem services? it provides.
Biodiversity forms the backbone of viable ecosystems on which we depend on for basic necessities, security, and health. By breaking down plant and animal matter, for example, insects and other invertebrates make nutrients available to plants and are integral to the carbon and nitrogen cycles. Other species pollinate crops, an essential service for farmers. Healthy ecosystems can mitigate or prevent flooding, erosion, and other natural disasters. These ecosystem services also play a hand in the functioning of our climate and in both air and water quality.
1. The reactivity among the alkali metals increases as you go down the group due to the decrease in the effective nuclear charge from the increased shielding by the greater number of electrons. The greater the atomic number, the weaker the hold on the valence electron the nucleus has, and the more easily the element can lose the electron. Conversely, the lower the atomic number, the greater pull the nucleus has on the valence electron, and the less readily would the element be able to lose the electron (relatively speaking). Thus, in the first set comprising group I elements, sodium (Na) would be the least likely to lose its valence electron (and, for that matter, its core electrons).
2. The elements in this set are the group II alkaline earth metals, and they follow the same trend as the alkali metals. Of the elements here, beryllium (Be) would have the highest effective nuclear charge, and so it would be the least likely to lose its valence electrons. In fact, beryllium has a tendency not to lose (or gain) electrons, i.e., ionize, at all; it is unique among its congeners in that it tends to form covalent bonds.
3. While the alkali and alkaline earth metals would lose electrons to attain a noble gas configuration, the group VIIA halogens, as we have here, would need to gain a valence electron for an full octet. The trends in the group I and II elements are turned on their head for the halogens: The smaller the atomic number, the less shielding, and so the greater the pull by the nucleus to gain a valence electron. And as the atomic number increases (such as when you go down the group), the more shielding there is, the weaker the effective nuclear charge, and the lesser the tendency to gain a valence electron. Bromine (Br) has the largest atomic number among the halogens in this set, so an electron would feel the smallest pull from a bromine atom; bromine would thus be the least likely here to gain a valence electron.
4. The pattern for the elements in this set (the group VI chalcogens) generally follows that of the halogens. The greater the atomic number, the weaker the pull of the nucleus, and so the lesser the tendency to gain electrons. Tellurium (Te) has the highest atomic number among the elements in the set, and so it would be the least likely to gain electrons.
Aluminum is an element. If there's nothing else in the foil
besides aluminum, then the foil is entirely an element.
Answer:
-191.7°C
Explanation:
P . V = n . R . T
That's the Ideal Gases Law. It can be useful to solve the question.
We replace data:
2.5 atm . 8 L = 3 mol . 0.082 L.atm/mol.K . T°
(2.5 atm . 8 L) / (3 mol . 0.082 L.atm/mol.K) = T°
T° = 81.3 K
We convert T° from K to C°
81.3K - 273 = -191.7°C
