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!
Explanation:
b. What useful functions do oxidation numbers serve?
It is used to show oxidation and reduction (loss and gain of electrons)
b. How many molecules are in 1 mole of molecules?
1 mole = 6.022 * 10^23 molecules
c. What is the name given to the number of molecules in 1 mole?
Avogadro's Number of molecules
21. a. What is the molar mass of an element?
This is the mass of an element divided by the number of moles.
Molar mass = Mass / Number of moles
b. Write the molar mass rounded to two decimal places of carbon, neon, iron and uranium.
amu = Atomic Mass Unit
Carbon = 12.01 amu
Neon = 20.18 amu
Iron = 55.85 amu
Uranium = 238.03 amu
you’re made partly of carbon so is clothes, furniture, plastics, yr household machines
Answer:
number of moles of NaCl produce = 12 mol
Explanation:
Firstly, we need to write the chemical equation of the reaction and balance it .
Na(s) + Cl2(g) → NaCl(s)
The balanced equation is as follows:
2Na(s) + Cl2(g) → 2NaCl(s)
1 mole(71 g) of chlorine produces 2 moles(117 g) of sodium chloride
6 mole of chlorine gas will produce ? mole of sodium chloride
cross multiply
number of moles of NaCl produce = 6 × 2
number of moles of NaCl produce = 12 moles
number of moles of NaCl produce = 12 mol
The periodic table is arranged in a way so that with each step the number of protons in the nucleus is increased by 1. It makes it for an easy choice to designate elements with numbers - atomic numbers, because in that case atomic number shows the number of protons possessed by the nucleus. Like this:
H has 1 proton
He has 2 protons
Li has 3 protons
Be has 4 protons and so on
Each proton has a charge of +1. The other particle present in the nucleus - the neutron - has zero electrical charge and thus irrelevant when computing the charge of a nucleus. It is easy to deduce that the nucleus charge equals the number of protons (which in turn equals the atomic number). So the nucleus charges are:
for H it's+1
for He it's +2
for Li it's +3
for Be it's +4 and so on
Atom is an electroneutral particle by definition. It means it's summed charge must be 0. Since we've looked at everything within the nucleus (the protons and the neutrons) it's time we turn our gaze to the space around it, which is full of orbiting electrons. Each electron has a charge of -1. To make up for the positive charge in the nucleus you have to fill the space aroung the nucleus with negative electrons.Thanks to the elementary nature of both proton and electron charge, you simply have to take the same number of electrons as that of protons! Like this:
H has 1 proton and 1 electron
He has 2 protons and 2 electrons
Li has 3 protons and 3 electrons
Be has 4 protons and 4 electrons and so on
Fe has atomic number 26. It means that Fe has 26 protons and 26 electrons. If it's a neutral atom
You typed 3. Is it accidental? If so, then the answer is above. If not, then you could be trying to type 56Fe +3, which means an ionic iron with charge +3. Charges are formed when you have too many or too few electrons to counter-balance the prositive charge of the nucleus. Charge +3 means you're 3 electrons short to negate the nucleus positive charge.
In other words, Fe+3 has 26 protons and 23 electrons.
