Half- life = 3.83 days
31 days/3.83 days = 8.093 half-life
Now we know that
After 1 half-life fraction of amount left = 1/2
After 8.093 half-life fraction left = (1/2)^8.093
atoms left = 3.0*10^7*(1/2)^8.093 = 109871.613 atoms = 1.09*10^5 atoms
Given: element: 3.0 times 10 7 th atoms of Radon, Rn, whose 1/2 life is 3.83...
Radon-222 (222 86 Rn) is a radioactive gas that is often found in homes as a byproduct of natural radiation in the ground. It has a mass of 222.017578u and a half-life of 3.8235 days. You are conducting an experiment on the effects of Radon on bacteria. You begin the experiment at 8:00 am on Monday when you introduce 4.00 µg of Radon-222. Later in the week you are concerned that the activity is too low for your experiment. How...
(1 point) Radon is a radioactive gas with a half-life of 3.82 d. If there are initially 460 decays/s in a sample, how many radon nuclei are left after 3 d 7
Why is the answer D? I got 9.9 * 10-1 g
45. The half-life of Rn-222 is 3.8 days. Starting with 1.0 g of Rn-222. how much will be left after 10 half-lives? Recall that radioactive decays obey first- order kinetics. A) 7.5 X 10-3 g B) 8.4 X 10-6 g C) 6.5 X 10-7 g D) 9.8 X 104 g
1-2
lodine-131 is often used in nuclear medicine to obtain images of the thyroid. If you start with 4.0x10 lodine-131 atoms, how many are left after approximately 1 month? 1-131 has a half- life of 8.0 days. 2) Radium-223 decays with a half-life of 11.4 days. How long will it take for a 0.240-mol sample of radium to decay to 1.50x 10 mol?
lodine-131 is often used in nuclear medicine to obtain images of the thyroid. If you start with...
The half-life of a radioactive isotope is 2.5 min. If there are initially 48 Times 10^32 atoms of this isotope, (a) the number of atoms of this isotope remaining after 15 min is: 12 Times 10^32 7.5 Times 10^31 3 Times 10^32 6 Times 10^4 3 Times 10^2 (b) what is the decay constant? (c) What is the initial activity?
1. (2 pts) Given the name or symbol for an element and its mass#, Fill in the table: Element # protons # neutrons # electrons 87Rb+ 128Te-2 2. (3 pts) Write the correct symbol and charge for the following: An atom with 47 protons, mass number 107, and 46 electrons. An atom with 2 more electrons than protons, mass number 80, and 46 neutrons. Write the atomic symbol for the element whose ion has a 2- charge, has 20 more...
1. The half-life of an element is 30 years. We start with 50 grams. Find a formula that gives the amount of the element remaining after h half-lives. Select one: a. 50 cross times 0.5 to the power of h b. 50 minus 0.5 cross times h c. 15 to the power of h d. 15 plus 0.5 to the power of h e. None of these 2. A bank account starts with $ 10. Every month, the amount in...
Concept check: element, compound formula, atoms, isotopes 1. Fill in the blank: Element symbol Name S AI P Fluorine Carbon Boron Bromine Cr Fe 2. Recognizing compound: Compound How many of each atom in one compound Elements in the compound HO 2 H, 10 H2O C.H.O. NaOH Caco CH,COOH NO. MealPO) Ba(NO)
1 mole of uranium-238 has potential to emit total energy equal to about A. 10^9 J B. 10^10 J C. 10^11 J D. 10^12 J Ps show your detail calculation. Pd-100 has a half-life of 3.6 days. If one had 6.02 times 10^23 atoms (209 gm) at the start, (a) How many atoms would be present after 20.0 days? (b) How much mass is left after 20.0 days?
1. How many electrons appear in the Lewis symbol for an element whose electron configuration is 1s'2s'2p? a. 2 b. d. 2. In which of the following ionic compounds are ions with a +2 charge present? a LiSe c Mg,Si d. SnO 3. The Roman numeral ." in the name iron(m) oxide indicates that: a. iron is present in the form of +3 ions b. there are three iron atoms per formula unit c. there are three oxygen atoms per...