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Tresset [83]
3 years ago
12

The half-life of sodium-24 is 15 days. A laboratory technician measures out a 72 g sample. Approximately how many grams of sodiu

m-24 would remain after 45 days?
Chemistry
1 answer:
Vanyuwa [196]3 years ago
6 0

Answer:

after 45 days 9 g left

Explanation:

Given data:

Half life Na-24 = 15 days

Mass of sample = 72 g

Mass remain after 45 days = ?

Solution:

Number of half lives passed:

Number of half lives = time elapsed / half life

Number of half lives = 45 days / 15 days

Number of half lives = 3

At time zero total amount = 72 g

After first half life = 72 g/ 2= 36 g

At 2nd half life = 36 g/2 = 18 g

At 3rd half life = 18 g/2 = 9 g

Thus after 45 days 9 g left.

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Answer:

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Explanation:

This is the equilibrium:

N₂(g) + 2H₂O(g) → 2NO(g) +2H₂(g)

And we have all the concentration at equilibrium:

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H₂ : 1.3M

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They are ok, because they are in MOLARITY. (mol/L)

Let's make the expression for Kc

Kc = ( [NO]² . [H₂]² ) / ([N₂] . [H₂O]²)

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