Nuclear Chemistry, Half-life Problems

What element is formed when the radioisotope Uranium-235 undergoes beta decay? Give atomic number and mass

Neptunium-235

How much of 30.0 grams of a substance will be left after 2 hours if the half-life is 15 minutes?

0.1171875 grams

An isotope of Cesium (Cesium-137) has a half-life of 30 years. If 1.0 mg of Cesium-137 disintegrates over a period of 90 years, how many mg of Cesium-137 remain?

0.125 mg

Sodium-25 was to be used in an experiment, but it took 3 minutes to get the Sodium from the reactor to the laboratory. If 5.0 g of Sodium-25 was removed from the reactor, how many g of Sodium-25 were placed in the reaction vessel 3 minutes later if the half-life of Sodium-25 is 60 seconds?

0.625 g

Thallium-201 has a half-life of 73 hours. If 4.0 mg of Thallium-201 disintegrates over a a period of 6 days and 2 hours, how many mg of Thallium-201 will remain?

1 mg

If the half life of uranium-235 is 703.8 million years. Today you have 200 g of uranium-235, how much uranium do you have in 1.408 billion years?

100 grams

The half-life of Polonium-218 is 3 minutes. Suppose you wanted to buy some of this isotope, and it required half an hour for it to reach you. How much should you order if you need to use 0.10 grams of this material?

102.4 grams

How much of a 100.0 gram sample of Au-198 is left after 8.10 days if it's half-life is 2.70 days?

12.5 grams

How many days will have passed if a substance has a half-life of 120 days and 50% of the substance remains?

120 days

Complete the nuclear equation..... 142/61 Pm + 0/-1 e = _____

142/62 Sm

The half-life of Cesium 137 is 30.2 years. What was the mass of the original sample if there are 11 g remaining after 120.8 years?

176 g

The half-life of Cobalt- 60 is 5.271 years. If there are 25.0 grams of the sample left after 15.813 years, how many grams were in the original sample?

200 grams

The half-life of K-42 is 12.4 hours. How much of a 750 gram sample is left after 62 hours?

22.5 grams

If the half life of carbon-14 is 5730 years. Today you have 200 g of carbon-14, how much carbon-14 do you have in 17,190 years?

25 grams

Actinium-226 has a half-life of 29 hours. If 100 mg of Actinium-226 disintegrates over a period of 58 hours, how many mg of Actinium-226 will remain?

25 mg

Complete the nuclear equation..... 38/19K = _____ + 0/-1 B

38/20 Ca

A 2.5 gram sample of an isotope of Strontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson island in the Pacific Test Site. The half-life of Strontium-90 is 28 years. How many years have passed if only 0.625 grams of this Strontium-90 remain?

56 years

The half-life of isotope X is 2 years. How many years would it take for a 4.0 mg sample of isotope X to decay and only have 0.50 mg of it remain?

6 years

A 50.0 gram sample of N-16 decays to 12.5 grams in 14.4 seconds. What is its half-life?

7.2 seconds

Selenium-83 has a half-life of 25 minutes. How many minutes would it take for a 10.0 mg sample to decay and have only 1.25 mg of it remain?

75 minutes

Calculate the neutron-to-proton ratio for the isotope Carbon-14

8 to 6

isotope

Atoms that have the same number of protons (and are therefore the same element) but different numbers of neutrons.

Write the balanced nuclear equation for the beta decay of the radioisotope Iron-60

Cobalt-60

What element is formed when the radioisotope Iron-60 undergoes alpha decay? Give atomic number and mass

Chromium-56

Every living organism on Earth contains a small, consistent, predictable fraction of which radioactive isotope?

Carbon-14, which has a half-life of 5730 years.

What are the products of the fusion of two hydrogen-1 atoms?

Helium-2

How are nuclear chain reaction rates controlled in a nuclear reactor?

Neutrons are absorbed or slowed down by graphite control rods and water surrounding the uranium in the reactor.

Write the balanced nuclear equation for the beta decay of the radioisotope Thorium-234

Pascalium-234

What element if formed when the radioisotope Thorium-242 undergoes alpha decay? Give atomic number and mass

Radium-238

fusion

Smashing smaller nuclei together to form larger nuclei. This releases even more energy than nuclear fission.

What subatomic particle causes the nuclear chain reaction in nuclear reactors and atomic bombs?

The neutron

Write the balanced nuclear equation for the beta decay of the radioisotope Pascalium-235

Uranium-235

Name one thing you can do change the rate of nuclear decay in a radioactive isotope.

You can't. The rate of radioactive decay is not changed by any factors that usually affect chemical reactions, such as adding or removing heat, raising or lowering pressure, etc.

alpha particle

a helium nucleus that is emitted from a radioactive atom.

beta particle

a high speed electron that is emitted from a radioactive atom. Neutron is transformed into a proton

gamma particle

a high-energy photon (particle of light) that is emitted from a radioactive nucleus. They have zero mass

Carbon-14

a long-lived naturally occurring radioactive carbon isotope of mass 14, used in carbon dating and as a tracer in biochemistry.

What type of decay occurs polonium-214 decays to lead-210?

alpha decay

Radioisotope used in smoke detectors, by alpha decay

americium-241

stable isotope

an "ordinary" element: does not break down and does not emit particles or rays.

radioisotope

an atom that emits alpha particles, beta particles, and/or gamma rays.

What type of decay occurs when Pascalium-234 turns to uranium-234?

beta decay

fission

breaking a large nucleus into smaller nuclei. This is what releases the energy in nuclear reactors and atomic bombs.

This isotope is used to estimate the age of living things years after they die. What is this dating technique called?

carbon dating.

Radioisotope used to treat prostate cancer, by beta decay

cobalt-60

What stops alpha?

paper

uranium-238

dating of rock formations and the age of earth

type of nuclear reaction found in nuclear power plants

fission

type of radioactive reaction found in the sun

fusion

used to sterilize medical equipment

gamma

What type of decay occurs between polonium-210 to polonium-210?

gamma decay

Radioisotope used to detect and treat thyroid disorders, by beta decay

iodine-131

Radioactive half-life

is the time for half the radioactive nuclei in any sample to undergo radioactive decay.

What stops gamma radiation?

lead or concrete

Write the balanced nuclear equation for the alpha decay of the radioisotope polonium-210

lead-206

What stops beta radiation?

metal

Radioisotope used to trace the flow of fertilizer through plants

phosphorus-32

nuclear radiation

the emission of alpha particles, beta particles, or gamma rays from the nucleus of an atom

mass number

the number of protons and neutrons in the nucleus of an atom

atomic number

the number of protons in the nucleus of an atom.

Write the balanced nuclear equation for the alpha decay of the radioisotope uranium-234

thorium-230

The largest natural element. Fuel for fission reactors

uranium (several isotopes)

radium-223

used to treat cancerous tumor by producing alpha particles

chain reaction

when one fission causes another and another