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kkurt [141]
3 years ago
11

Niobium-91 has a half-life of 680 years. After 2,040 years, how much niobium-91 will remain from a 300.0-g sample? 3 g 18.75 g 3

7.5 g 100.0 g
Chemistry
2 answers:
Vadim26 [7]3 years ago
7 0
Amount of Niobium-91 initially
= 300/91 =3.2967mol
2040 years = 3 ×680 = 3 half-lives
therefore, amount left = 0.4121mol
mass of Niobium-91 remaining = 0.4121 ×91 =37.5g
Maslowich3 years ago
7 0
The correct answer is letter c 


hope i helped
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FCH_{2}COOH(aq) + H_{2}O (l)    FCH_{2}COO^{-}(aq)+ H_{3}O^{+}(aq)

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4 0
3 years ago
A volume of a fixed gas is doubled and the temperature is doubled. What happens to the pressure of the gas?
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Hope this helps!

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