<span>the average atomic mass of this element is 39.95 u</span>
Answer:
3.74%
Explanation:
We express a solution's volume by volume percent concentration, % v/v,
Take the ratio of the isopropyl alcohol (IPA) volume to the total volume of the solution, which is 1800 mL of water+ 70 mL of IPA,
and multiply by 100 to get the percentage: 70/(1800+70) *100 = 0.0374*100 = 3.74%
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
Answer: Petroleum or Natural gas and Kerosine
Explanation: