⚡️science test retake questions ⚡️

What's a similarity between fission and fusion

C) They both result in products that have less mass than the reactants.

All decays

Release radiation

A radioactive isotope has a half-life of ten days. How much of a 100 gram sample will be left after 20 days?

B) 25.0 grams

What is the half-life of Cobalt-57?

10 days

If 50-grams of Cobalt-57 remained after 10 days. What was the original amount of the sample?

100 grams

Archaeologists use the radioactive decay of carbon-14 to estimate the age of fossils and can be used on samples of bone, cloth, wood and plant fibers. The half-life of carbon-14 is 5,730 years. Several human bones have been unearthed at an archaeological dig. 25% of the original carbon-14 isotope is remaining and scientists estimate the bones to be ___________ years old.

11460

A 50-gram sample has a half-life of 12 days. How much material will remain after 12 days?

25 grams

How much of 100-gram sample of cobalt-57 will remain after 10 days

25 grams

A radioactive isotope has a half-life of ten days. How much of a 100 gram sample will be left after 20 days?

25. Why? Since the half-life is 10 days, 20 days equals 2 half-lives. If you start with 100g, after 10 days it will decay to 50g. After the second half-life, the amount should be cut in half once again. This yields an answer of 25.0 grams.

What is the half-life for a substance in which 25% of the original remains after 10 days?

5 days

A radioactive isotope of potassium (K) has a half-life of 20 minutes. If a 40.0 gram sample of this isotope is allowed to decay for 80 minutes, how many grams of the radioactive isotope will remain?

A) 2.5 grams why? Because it goes through 80 minutes, this is 4 half-lives, 80/20=4. During each half life, the amount is reduced by a factor of 1/2. So, it goes from 40g to 20g, 20g to 10g, 10g to 5g and finally, 5g to 2.5g.

Cobalt-60 is a radioactive element with a half-life of 5.27 years. Cobalt-60 atoms decay by releasing both beta and gamma radiation. What element is produced by this process of nuclear decay?

A) Nickel-60

Barium-142 is used as a GI radiocontrast agent. After 1.25 hours, 9.25 μg remains in the patient. Determine the original dose given the half-life of Ba-142 is 10.6 minutes.

D) 1,180 μg

18) Two isotopes of hydrogen fuse to form a neutron plus the larger element,

D) helium.

alpha decay

Decreases the number of protons in the parent nuclide

Beta decay and gamma decay

Do not alter the mass of the parent nuclide

beta decay

Increases the atomic number of the parent nuclide

Nuclear fission produces about one-fifth the power in the United States. An unintended positive consequences of nuclear power has been that

Less greenhouse gases

gamma decay

Wave nature