Answer : The number of moles of oxygen needed are, 1.5 moles.
Explanation :
The balanced chemical reaction will be:
Now we have to calculate the moles of oxygen.
From the balanced chemical reaction we conclude that,
As, 6 moles of water vapor produces from 5 moles of oxygen
So, 1.80 moles of water vapor produces from 
moles of oxygen
Therefore, the number of moles of oxygen needed are, 1.5 moles.
Molar mass :
NaBr = 103 g/mol
Pb(NO3)2 = 331.20 g/mol
<span><span /><span>Balanced chemical equation :
</span></span>2 NaBr + 1 Pb(NO3)2 = 2 NaNO3 + 1 PbBr<span>2
</span><span>
2*103 g NaBr ------------> 1 * 331.20 g Pb(NO3)2
g NaBr -------------------> 311 g Pb(NO3)2
331.20 g = 2*103*311
331.20 g = 64066
mass ( NaBr ) = 64066 / 331.20
mass ( naBr) = 193,43 g of NaBr
hope this helps!.
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A wave with low energy will also have long wavelengths and low frequencies.
The given in a single photon of a wave is given by Planck's equation:
E = hc/λ
and
E = hf
Where λ is the wavelength and f is the frequency of the photon. This means that energy is directly proportional to the frequency and inversely proportional to the wavelength. Thus, it is visible that photons with a lower frequency and a longer wavelength will have a lower energy.
