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3 years ago

5

La is element 57 on the periodic table a sample contains 2.82 * 10€25 power atoms of La calculate the amount of LA

1 answer:

vodka [1.7K]3 years ago

5 0

Answer:

$n=46.8molLa\\\\m=6.50x10^3gLa$

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate both moles and grams of lanthanum by using the Avogadro's number as a relationship of atoms to moles and its atomic mass as a relationship to moles to grams to obtain the following:

$n=2.82x10^{25}atomsLa*\frac{1molLa}{6.022x10^{23}atomsLa}=46.8molLa\\\\m=46.8molLa*\frac{138.9gLa}{1molLa} =6.50x10^3gLa$

Regards!

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A sample of helium gas has a volume of 1.25 L and a temperature of 22 °C, under a constant pressure. What is the new volume if t

Digiron [165]

Answer:

the new volume is 1.35L

Explanation:

The computation of the new volume in the case when the temperature rises to 45 degrees is shown below:

GIven that

Volume = 1.25L

And, the temperature is 22 degrees celsius

So, $T_1$ = (275 + 22)k

= 297 k

Now

$T_2$ = (275 + 45)k

= 320 k

Now as it is a constant pressure

So, the new volume is

$\frac{V_1}{T_1} = \frac{V_2}{T_2} \\\\V_2 = \frac{V_1}{T_1}\times T_2 \\\\= \frac{1.25}{297}\times 320$

= 1.35L

hence, the new volume is 1.35L

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