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Snowcat [4.5K]
3 years ago
11

A particular graduated cylinder contains 24.0 mL Br2(liquid). The density of bromine at 25 degrees C is 3.12g/cm^3. Note that in

nature, elemental bromine exists in diatomic form(that is, as Br2)
How many representative particles(molecules of Br2) are in the cylinder?
Chemistry
1 answer:
motikmotik3 years ago
4 0

Answer:

2.82x10^{23}molecules

Explanation:

Hello.

In this case, given the volume (1cm³=1mL) and density of the bromine we are to firstly compute the mass since it will allow us to compute the representative particles:

\rho =\frac{m}{V}

m=\rho *V=3.12g/cm^3*24.0cm^3\\\\m=74.88gBr_2

Next, since the mass of one mole of diatomic bromine is 159.82 g (one bromine weights 78.91), we can next compute the moles in that sample:

n=74.88g*\frac{1mol}{159.82g} =0.469molBr_2

Finally, via the Avogadro's number we can compute the representative particles of bromine as follows:

particles=0.469mol*\frac{6.022x10^{23}molecules}{1mol}\\ \\2.82x10^{23}molecules

Best regards.

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Explanation:

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In given question it is stated that the half life thorium-234 is 25 days. Which means after passing the 25 days the amount of thorium must be halved of original amount.

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After 50 days amount of thorium left:

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