Nuclear chemistry Questions and Answers

Iodine-131 is radioactive and has a half life of 8.04 days. What percentage of a sample would be left after 36.4 days? Round your answer to 2 significant digits. 00 % ×10 x 3 ?

The potassium-38 nuclide radioactively decays by positron emission. Write a balanced nuclear chemical equation that describes this process. X Ś Y

The half-life of silicon-32 is 710 years. If 40 grams is present now, how much will be present in 700 years? (Round your answer to three decimal places.)

Cesium-137 is radioactive and has a half life of 30. years. Calculate the activity of a 5.2 mg sample of cesium-137. Give your answer in becquerels and in curies. Round your answer to 2 significant digits.

The carbon-11 nuclide radioactively decays by positron emission. Write a balanced nuclear chemical equation that describes this process.

Radium-226 is radioactive and has a half life of 1600. years. How much of a 6.70 mg sample would be left after 3.47 × 10³ years? Round your answer to 2 significant digits. Also, be sure your answer has a unit symbol.

MERE Suppose a samarium-147 nuclide decays into a neodymium-143 nuclide by emitting an alpha particle. 2012 Complete the nuclear chemical equation below so that it describes this nuclear reaction.

Suppose a potassium-38 nuclide decays into an argon-38 nuclide by emitting a positron. Complete the nuclear chemical equation below so that it describes this nuclear reaction. 38 19 1 0 00

The uranium-238 nuclide radioactively decays by alpha emission. Write a balanced nuclear chemical equation that describes this process.

The yttrium-88 nuclide radioactively decays by electron capture. Write a balanced nuclear chemical equation that describes this process.

On your own paper, write the equation for the nuclear reaction described in each of the following processes: 1. The transmutation that occurs when a scandium-48 nucleus undergoes beta decay. 2. Americium-241 undergoes alpha decay (inside a smoke detector) 3. Technetium-99 (99mTc) undergoes gamma decay to form 99Tc Upload your equations. Posted Today at 9:13 am Comments

What is the ground state of an element? Select one: It is the most energetically favorable arrangement of the element's electrons. It is the arrangement of electrons that occurs at room temperature or below. It is the arrangement of electrons that occurs after one or more electrons becomes excited. It is the most energetically favorable arrangement of the element's protons.

To resolve an object in an electron microscope, the wavelength of the electrons must be close to the diameter of the object. What kinetic energy, Ek, must the electrons have in order to resolve a protein molecule that is 7.60 nm in diameter? Take the mass of an electron to be 9.11 x 10-³1 kg. Ex = x10 x10 TOOLS

(5 points) In a certain sci-fi movie, machines take over the Earth and use human body heat as an energy source. If humans are 37°C, and the environment is 20°C, what is the maximum possible efficiency of this process? Explain your reasoning.

32p has a half-life of 14.3 days. The original sample of 32p has a mass of 1.88mg. Approximately what mass of P-32 will remain after 6 half-lives? 0.188 mg 0.0588 mg 0.352 mg 0.0294 mg 0 0.101 mg None of the answers are correct.

An isotope with a half-life of 18.0 seconds was produced in a physics lab as a by-product of a reaction. Exactly how many half-lives pass after 126 seconds have elapsed? Enter only a number.

Curium-240 has a half-life of 27 days. The original sample of curium-240 has a mass of 0.874 mg. Approximately what mass of Cm-240 will remain after 5 half-lives? 0.175 mg 0.0625 mg 0.135 mg 0.0273 mg 0.361 mg None of the answers are correct.

Which of the following statements is true about both nuclear fusion and nuclear fission? They occur in the sun. Heavy atoms are split. Two light nuclei combine. Some mass changes into energy.

Indium-116 is radioactive and has a half life of 14.10 seconds. Calculate the activity of a 1.9 mg sample of indium-116. Give your answer in becquerels and in curies. Round your answer to 2 significant digits.

Consider the fission of uranium-235. a. The fission of uranium-235 begins with the addition of a neutron to the nucleus What isotope is formed? Give the isotope symbol. b. After the neutron is added, the uranium atom is more unstable and undergoes fission. A possible set of products is krypton-94, barium-139, and 3 neutrons. How many protons are in these products? c. Were any protons lost?

Write a nuclear equation for the fission of uranium-235 by neutron bombardment to form antimony-133, three neutrons, and one other isotope.

How much phosphorus-32 remains from a 8.00 g sample after each of the following number of half- lives: (a) 3; (b) 9? g of phosphorus-32 remains. g of phosphorus-32 remains.

A certain element consists of two stable isotopes. The first has an atomic mass of 7.0160 amu and a percent natural abundance of 92.58%. The second has an atomic mass of 6.0150 amu and a percent natural abundance of 7.42 %. What is the atomic weight of the element?

A wooden object from a prehistoric site has a carbon-14 activity of 10 cpm compared to 40 cpm for new wood. If carbon-14 has a half-life of 5730 yr, what is the age of the wood? 22 900 yr 17 200 yr 1430 yr 5730 yr 11 500 yr

Light gathering power of optical telescopes is dependent on the of the lens. shape thickness size refractive Index

Splitting of the nucleus of an atom is called chemical reaction nuclear fission nuclear fusion chemical bonding

Be sure to answer all parts. Compare the wavelengths of an electron (mass=9.11 × 10-31 kg) and a proton (mass = 1.67 x 10-27 kg), each having (a) a speed of 3.52 x 106 m/s and (b) a kinetic energy of 1.88 × 10-15 J. Enter your answers in scientific notation. (a) Electron wavelength = __ x 10 __ m Proton wavelength = __ x 10 __ m (b) Electron wavelength = __ x 10 __ m Proton wavelength = __ x 10 __ m

Use the Rydberg equation to calculate the wavelength (in nm) of the photon emitted when an electron in a hydrogen atom undergoes a transition from n = 6 to n = 2.

Identify the isotope used in farm animals' body composition analysis. Phosphorous-40 Potassium-40 Calcium-45 Sodium-24

Infrared radiation has frequencies from 3.0×10¹1 to 3.0x10¹4 Hz, whereas the frequency region for X-ray radiation is 3.0×1016 to 3.0×10¹⁹ Hz. We can say that: 1. The speed of infrared radiation is ___ X-ray radiation. 2. The wavelength of infrared radiation is ____ X-ray radiation.

Plutonium-238 is an a emitter and a compact heat source. Coupled with a PbTe thermoelectric device, it was once used as a very reliable electrical energy source for cardiac pacemakers. What is the product of the radioactive decay of plutonium-238? A Thorium-230 B. Uranium-234 C. Californium-246 D. Plutonium-234 238 Pu ⇒ a particle + ?

Two nitro (NO₂) groups are chemically bonded to a patch of surface. They can't move to another location on the surface, but they can rotate (see sketch at right). It turns out that the amount of rotational kinetic energy each NO, group can have is required to be a multiple of e, where E=1.0 × 10 -24 J. In other words, each NO, group could have e of rotational kinetic energy, or 2e, or 3ɛ, and so forth - but it cannot have just any old amount of rotational kinetic energy. Suppose the total rotational kinetic energy in this system is initially known to be 188. Then, some heat is removed from the system, and the total rotational kinetic energy falls to 14ɛ. Calculate the change in entropy. Round your answer to 3 significant digits, and be sure it has the correct unit symbol. ► Two rotating NO, groups bonded to a surface.

The first has a mass of 35.0 u and a percent natural abundance of 75.5%. The second has a mass of 36.9 u and a percent natural abundance of 24.5 %. What is the atomic mass of the element? u

Cameron is a doctor treating a cancer patient, Billy is an archeologist dating a vase, and Isabelle is a geologist dating a layer of soil. Which isotopes would each person most likely use? (a) Cameron would use carbon-14, Billy would use cobalt-60 (which releases gamma rays), and Isabelle would useuranium-238. (b)Cameron would use cobalt-60 (which releases gamma rays), Billy would use carbon-14, and Isabelle would use uranium-238. (c) Cameron would use uranium-238, Billy would use carbon-14, and Isabelle would use cobalt-60 (which releases gamma rays). (d) Cameron would use cobalt-60 (which releases gamma rays), Billy would use uranium-238, and Isabelle would use carbon-14.

The beryllium-10 nuclide radioactively decays by beta emission. Write a balanced nuclear chemical equation that describes this process.

The table below lists information about two common types of nuclear radiation. Fill in the missing information. Note: round masses to the nearest atomic mass unit (u). name matter or energy? mass(u) charge(e) can be stopped by gamma matter ______ _______ __________ energy ________ matter 4 +2 ___________ energy

Suppose an aluminum-27 nuclide transforms into a sodium-24 nuclide by absorbing a neutron and emitting an alpha particle. Complete the nuclear chemical equation below so that it describes this nuclear reaction.

If a rock sample was found to contain 6.93 x 10^-7 mol of argon-40, how much potassium-40 would also have to be present for the rock 1.3 x 10^9 years old? The half-life of K-40 is 1.3 x 10^9 years. ______ mol K-40

Find the half-life of a radioactive element, which decays according to the function A(t) = A₀e‾⁰∙⁰³⁸⁴ᵗ, where t is the time in years. The half-life of the element is ___________years.

The technetium-99 nuclide radioactively decays by beta emission. Write a balanced nuclear chemical equation that describes this process.

Properly order the following steps for a U-235 nuclear fission chain reaction 1. 9 neutrons are now able to bombard other U-235 isotopes 2. A neutron bombards a U-235 isotope 3. Two new isotopes are created along with 3 neutrons 4. 3 neutrons bombard 3 other U-235 isotopes

What is the process called where 2 H isotopes combine to form an alpha particle, a neutron, and energy? a. Radioactivity b. Alpha Decay c. Nuclear Fusion d. Chain Reaction e. Nuclear Fission

If 12 g of a radioactive substance are present initially and 9 yr later only 6 g remain, how much of the substance will be present after 11 yr? After 11 yr there will be g of a radioactive substance. (Round the final answer to three decimal places as needed. Round all intermediate values to seven decimal places as needed.)

We ended with 15 grams of Xenon-131 and 3 half lives have passed. a. What element was it originally? (What was its radioactive version) b. How much of this radioactive element did we originally have? (Hint: This was Beta decay)

If we started with 65 grams of Gold-198 a. What daughter element will be produced? b. How much of that element will be present after 4 half lives? c. How much time has passed?

Which statement about nuclear reactions is NOT true? in fission, nuclei are split and in fusion, nuclei are combined nuclear reactions release small amounts of energy nuclear reactions involve changing the identity of the atom in fission, the total mass of the reactants equals the total mass of the products

What is the half-life of a 100.0 g sample of nitrogen-16 that decays to 6.25 g of nitrogen-16 in 21.6 s? 64.8 seconds 10.8 seconds 43.2 seconds 7.2 seconds none of these choices is correct

Write balanced nuclear equations for the decay of the radioactive particles below. 1. Radon-226 decays to produce an alpha particle and a gamma ray. 2. Gallium-70 decays to produce a beta particle.

Complete the following nuclear equations. Write the mass number, atomic number, and symbol for the remaining particle.

TUTOR Radiochemical Dating half-life rate constant, k disintegrations per minute (No) elapsed time (age) Radiochemical dating works on the principle that the quantity of radiation emitted from a sample is proportional to the quantity of radioactive isotope present. Therefore, comparing the radioactivity of an old sample (at time t) to that of a new sample (at time 0) can give the ratio of masses (or amounts) of the radioactive isotope present in each. This ratio can then be used to calculate the time elapsed. Step 1 Use the half-life to calculate the rate constant for the reaction. All radioactive decay processes are first order, so k = 0.693/t1/2- Step 2 Experimentally determine the number of disintegrations per minute for the artifact and for carbon in living matter. The ratio of these two values is equal to N₂/No. Step 3 Solve for time elapsed. The carbon-14 activity of an artifact from a burial site was 6.0 min¹g¹. The half-life of carbon-14 is 5730 years, and the current carbon-14 activity is 16.1 min¹g¹ (that is, 16.1 disintegrations per minuts per gram of carbon). How old is the artifact? y