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denis23 [38]
3 years ago
10

What did Stephen hawking do that was important

Chemistry
1 answer:
azamat3 years ago
4 0
Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics.
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What is minimum volume of oxygen required to react with 42.5 g of aluminum in the synthesis of aluminum oxide at stp?
natka813 [3]
<span>26.833 liters

Aluminum oxide has a formula of Al</span>₂O₃,<span> which means for every mole of aluminum used, 1.5 moles of oxygen is required (3/2 = 1.5).

Given 42.5 g of aluminum divided by its atomic mass (26.9815385) gives 1.575 moles of aluminum.

Since it takes 1.5 moles of oxygen per mole of aluminum to make aluminum oxide, you'll need 2.363 moles of oxygen atoms.

Each molecule of oxygen gas has 2 oxygen atoms, so the moles of oxygen gas will be 2.363/2 = 1.1815

Finally, you need to calculate the volume of </span>1.1815 <span>moles of oxygen gas.
1 mole of gas at STP occupies 22.7 liters of volume. Therefore,

1.1815 * 22.7 = </span>26.8 liters <span>of oxygen gas.
</span>
6 0
4 years ago
Use the provided reduction potentials to calculate ArGº for the following balanced redox reaction: Pb2+(aq) + Cu(s) → Pb(s) + Cu
nydimaria [60]

Answer : The correct option is, +91 kJ/mole

Solution :

The balanced cell reaction will be,  

Cu(s)+Pb^{2+}(aq)\rightarrow Cu^{2+}(aq)+Pb(s)

Here copper (Cu) undergoes oxidation by loss of electrons, thus act as anode. Lead (Pb) undergoes reduction by gain of electrons and thus act as cathode.

First we have to calculate the standard electrode potential of the cell.

E^0_{[Pb^{2+}/Pb]}=-0.13V

E^0_{[Cu^{2+}/Cu]}=+0.34V

E^0_{cell}=E^0_{cathode}-E^0_{anode}

E^0_{cell}=E^0_{[Pb^{2+}/Pb]}-E^0_{[Cu^{2+}/Cu]}

E^0_{cell}=-0.13V-(0.34V)=-0.47V

Now we have to calculate the standard Gibbs free energy.

Formula used :

\Delta G^o=-nFE^o_{cell}

where,

\Delta G^o = standard Gibbs free energy = ?

n = number of electrons = 2

F = Faraday constant = 96500 C/mole

E^o = standard e.m.f of cell = -0.47 V

Now put all the given values in this formula, we get the Gibbs free energy.

\Delta G^o=-(2\times 96500\times (-0.47))=+90710J/mole=+90.71kJ/mole\approx +91kJ/mole

Therefore, the standard Gibbs free energy is +91 kJ/mole

6 0
3 years ago
6. Why does the sun seem to change position in the sky?
Dafna11 [192]
A. Earth’s Rotation
4 0
3 years ago
Explain light and waves and the properties of both.
yKpoI14uk [10]

Answer:

Electromagnetic waves are typically described by any of the following three physical properties: frequency (f), wavelength (λ), or intensity (I). Light quanta are typically described by frequency (f), wavelength (λ), or photon energy (E).

Explanation:

please mark as brainlist

6 0
3 years ago
Compute the number of grams(g) of lead in 22.5 moles of lead.
iogann1982 [59]

Answer:

4662 in grams

Explanation:

hope this helps :).

7 0
3 years ago
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