Answer:
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Step-by-step explanation:
Answer:
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
Please give brainliest
Answer:
Step-by-step explanation:
d= 2r
therefore the radius is 1
Answer:
1/289 or 0.03462749213
Step-by-step explanation:
33 / 9537
= 1/289 or 0.03462749213
Answer:
18
Step-by-step explanation:
10/0.5 = 20
20 * 0.9 = 18