Answer : True
Explanation : When storing parts outside it is best to keep them under tarps or wrapped to stay in compliance is true, because when we store the parts outside the house there are high chances of the parts getting exposed to environmental moisture. Which will develop rust on the parts and make it useless later on. To avoid this situation it is safer to keep it covered under the tarps or wrap it with something which can protect it from moisture.
Answer:
25 gm would be left
Explanation:
45 hours is 3 half lives
200 gm * 1/2 * 1/2 * 1/2 = 25 gm
Answer:
67.6 years is the time the isotope take to decay from 0.900g to 0.170g
Explanation:
The radioactive decay follows first order law:
Ln [A] = -kt + ln[A]₀
<em>Where [A] is concentration after time t,</em>
<em>k is decay constant:</em>
<em>k = ln 2 / t(1/2)</em>
<em>k = ln2 / 28.1 years</em>
<em>k = 0.02467 years⁻¹</em>
<em>[A]₀ = Initial concentration.</em>
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We can replace concentration and use the mass of the isotope:
Ln [A] = -kt + ln[A]₀
Ln [0.170g] = -0.02467 years⁻¹t + ln[0.900g]
-1.667 = -0.02467 years⁻¹t
t =
<h3>67.6 years is the time the isotope take to decay from 0.900g to 0.170g</h3>
Start with the 19.7 mol HNO3. use dimensional analysis to correctly convert from mol HNO3 to gram H2O. so, it should look similar to 19.7 mol HNO3 x (2 mol H2O/6 mol HNO3) x (18 g H2O/1 mol H2O)
the first parenthesis’ numbers were received from the balanced equation (for every 6 mol HNO3, 2 mol H2O formed). the second is converting from moles to grams by using the molar mass of H2O (1+1+16). you should get 709.2/6. once you divide those, the answer should be 118.2 g H2O. I’m not sure if your computer requires you to use the exact answer or stop at the correct number of significant digits, but if it does then it might just be 118. g H2O.
