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Half-Life

Produce energy commercially by fusion; Dating using carbon-14

1. (A) Efforts are underway to produce energy commerically by fusion. It is too difficult to produce helium by fusion of protons, as is done in the sun, so we have to start with heavier nuclei such as deuterons. One possible reaction is Calculate the energy, in MeV, released in this reaction. (4.032 MeV) The abundance of de

Radiation Biological Damage and Bohr Model of Atoms

1. An electron drops from the L shell to the K shell and gives off an X-ray with a wavelength of 0.0205 nm. What is the atomic number of this atom? Answer 78 2. A radioactive substance has a decay constant equal to 8.9x10^-3s-1. What is the half-life of this substance? Answer 78sec 3. How many rad of 200-keV X-rays caus

Rate of Radioactive Decay

226-88 Ra, a common isotope of radium, has a half-life of 1620 years. Knowing this, calculate the first order rate constant for the decay of radium-226 and the fraction of a sample of this isotope remaining after 100 years.

10 Chemistry Problems on half-life and formation

11. The half-life of a first-order reaction is 13 min. If the initial concentration of reactant is 0.085 M, it takes _____ min for it to decrease to 0.055 M. a. 8.2 b. 11 c. 3.6 d. 0.048 e. 8.4 12. The mechanism for formation of the product X is:

Circular Conducting Loops Carried

Question 84 (a) A circular conducting loop carries a current of 5.0 A and has radius 30 mm (i) Calculate the magnetic field at the centre of the loop (H) How many turns would be needed to give a field of 1.0 mT (b) A electron is injected into the 1.0 mT magnetic field mentioned in part (a) with a velocity of 2500 m S-lin a

Radioactive decay

Radioactice substances decay exponentially. The amount of radium present at an time t obeys the law Q(t)= Qoe^-kt, where Qo. is the initial amount present and k is a suitable positive constant. The half-life of a radioactive substance is the time required for a given amount to be reduced by one-half. Now, it is known that the ha

Half-Life

At 300 K the reaction below obeys the rate law Rate=k[NOCl]^2, where k=2.8 X .000010 M to the neg 1 times s to the neg 1. 2 NOCl >>>>>> 2NO + Cl2 Suppose 1.0 mole of NOCl is introduced into a 2.0-liter container at 300 K. Evaluate the half-life of the reaction.

Zero and Second Order Reaction

The second order reaction for the decomposition of nitrosyl bromide has a half life of 12.5s at a concentration of 0.100M. NOBr(g)-->NO(g) + 1/2Br2(g) I need help finding k for the reaction, and how would I find how long it will take to decompose 80 % of a 0.0500M solution of nitrosyl bromide, and how fast 0.200M solutio

What is the specific activity of the air inside?

a) Tritium (H-3) has a radiological half-life of 12.3 years. What is its specific activity in units of Bq/g and Ci/g? b) A 0.2 gram sample of Kr-85 gas, which decays into stable Rb-85, is accidentally broken and escapes into a sealed warehouse measuring 40 x 30 x 20 m. What is the specific activity of the air inside in Bq/cm^

Nuclear Medicine Clarification

Email me for Clarification. I only need Parts C and D... I solved A and B, the answers are below. Not too much work left for 25 credits. Your help is appreciated. The only radiogenic lead isotope that is not either stable (Pb-206, 207, 208) or with a halflife of less than one day is Pb-210, which is found in nature in sec

Relativity

At standard Temperature and pressure sound travels at speed u=330m/s relative to the air through which it propagates. Four students A,B,C and D position themselves as shown if figure 1.20 (see attachment), with A,B,C in a straight line and D vertically above B. A steady wind is blowing with speed 30m/s along the line ABC. If

Radioactive decay

A threory of nuclear astrophysics is that all the heavy elements like uranium are formed in supernova explosions of massive stars, which immediately release the elements into space. If we assume that at the time of the explosion there were equal amounts of 235U and 238U, how long ago were the elements that formed our Earth rele

Radioactive decay: Example problem

Find the half-life of a radioactive material if, after one year 99.5713% of the amount remains, also write the formula for finding the amount of this material after (t) years, and how much will remain in 500 years?

Carbon-14 Content

The age of a piece of wood from an ancient source is determined by carbon dating. The carbon-14 content of a sample of the wood is found to be one-fourth that of living trees. The half life of carbon-14 is 5730 years. How old is the piece of wood?

Quantities that could be modelled by exponential growth or decay

Select the three options which are NOT examples of quantities that could be modeled by exponential growth or decay. Options A. The number of students registering for named degress at the Open University, if each year there are 5% more than the previous year. B. The world's reserve of a certain mineral, given that 1000

Half life of Ge

A 1.00g of sample of Ge decays to 0.87 in 1.9hr. What is the half-life of Ge? Please show how you arrive at the solution. thanks a. 1.4 x 10(exponent 1)hr b. 9.5 hr c. 1.1 x 10(exponent negative 1) hr d. 7.3 x 10(exponent negative 2) hr e. 13 hr