## What isotope has a half-life of 4.5 billion years?

Parent Isotope | Stable Daughter Product | Currently Accepted Half-Life Values |
---|---|---|

Uranium-238 |
Lead-206 |
4.5 billion years |

Uranium-235 | Lead-207 | 704 million years |

Thorium-232 | Lead-208 | 14.0 billion years |

Rubidium-87 | Strontium-87 | 48.8 billion years |

## What percent of parent isotope would remain after 4 half lives?

**62.5 g**of the parent isotope will remain. After 5 half-lives (2500 years) 31.25 g of the parent isotope will remain. After 6 half-lives (3000 years) 15.625 g of the parent isotope will remain.

## How do you calculate age from a half-life?

## How do you determine the half-life of an isotope?

## How do you calculate half-life physics?

## What is the half-life of uranium 235?

**about 700 million years**and uranium-234 about 25 thousand years.

## What percentage remains after 4 half-lives?

After 4 half-lives there will be **6.25%** of the original isotope and 93.75% of the decay product.

## When 4 half-lives have gone by what percent of the original parent product still remains in a rock?

…

KEY: Half-Life Calculations.

Element | Uranium |
---|---|

Parent Isotope | U-238 |

Daughter Isotope | Pb-206 (Lead) |

Half-life | 4.5 billion years |

## What parent isotopes could be used to date a rock that is 4 billion years old?

Two isotopes of uranium are used for radiometric dating. **Uranium-238** decays to form lead-206 with a half-life of 4.47 billion years. Uranium-235 decays to form lead-207 with a half-life of 704 million years. Uranium-lead dating is usually performed on crystals of the mineral zircon (Figure 11.26).

## What is the formula for half-life in chemistry?

The half-life of a reaction is the time required for the reactant concentration to decrease to one-half its initial value. The half-life of a first-order reaction is a constant that is related to the rate constant for the reaction: **t _{1}_{/}_{2} = 0.693/k.**

## How do you solve for half-life in math?

## What is the half-life formula calculus?

**ln 2 k**. Half-life = ln 2 k .

## What is half-life of isotope?

one-half

The half-life of a radioactive isotope is the amount of time it takes for one-half of the radioactive isotope to decay. The half-life of a specific radioactive isotope is constant it is unaffected by conditions and is independent of the initial amount of that isotope. Consider the following example.Jul 31 2021

## What determines half-life?

A ‘half-life’ is defined as **the amount of time taken for the number of nuclei present in a sample at a given time to exactly halve**. This value does not depend on the moment chosen: the amount of time taken for the nuclei to halve will always be the same.

## What is an isotope half-life quizlet?

definition of half life. **the time taken for the radioactivity of a specified isotope to fall to half its original value**. a half life of a radioactive substance is. the time it takes to get half its radioactivity to go away.

## What is Half-Life in nuclear physics?

_{1}

_{⁄}

_{2}) is

**the time required for a quantity to reduce to half of its initial value**. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.

## What is the nuclear equation?

Nuclear equations **represent the reactants and products in radioactive decay nuclear fission or nuclear fusion**. Instead of chemical equations where it shows the different number of elements is conserved in a reaction in a nuclear reaction the atomic mass and proton number are conserved.

## How do you find half-life given percentage and time?

## What is the formula for uranium-235?

Uranium-235 Symbol

The symbol or formula for this radioactive isotope is ** ^{235}U**. It is also denoted by U-235.

## What is the half life of uranium 237?

Mass Number | Half-life | Decay Mode |
---|---|---|

237 | 6.75 days |
Beta-minus Decay |

238 | 4.468×10 ^{9} years |
Spontaneous Fission |

Alpha Decay | ||

239 | 23.45 minutes | Beta-minus Decay |

## What does the 235 represent in uranium-235 quizlet?

In terms of protons neutrons and electrons what does the 235 mean? Uranium atom contains **92 protons in the nucleus**. Why is uranium-235 an ideal isotope to use for nuclear technology compared to something like carbon-12? It Contains a large nucleus that can be split when truck by fast moving neutron.

## What percent of the parent isotope remains after 2 half-lives?

After two half-lives **75%** of the original parent atoms have been transformed into daughter products (thus only 25% of the original parent atoms remain). After three half-lives only 12.5% of the original parent atoms remain. As more half-lives pass the number of parent atoms remaining approaches zero.

## What fraction of a radioactive isotope remains after 4 half-lives have occurred?

Number of Half-Lives Passed | Fraction Remaining | Percentage Remaining |
---|---|---|

2 | 1/4 | 25 |

3 | 1/8 | 12.5 |

4 | 1/16 | 6.25 |

5 | 1/32 |
3.125 |

## How many half-lives have passed if a substance is left with 3.125 percent of the original amount?

**5 half lives**have passed.

## How many half-lives have passed if a rock contains 25% parent isotopes and 75% daughter isotopes?

**two half-lives**must have passed.

## How many half-life periods have passed if a fossil contains 1/32 of the original amount of carbon 14?

**5 half lifes**.

## What would you expect the half-life of the isotope used to date the age of Earth at 4.6 billion years to be?

Two uranium isotopes are used for radiometric dating. Uranium-238 decays to lead-**206** with a half-life of 4.47 billion years.

## What is the parent to daughter isotope ratio of 1 half-life has passed?

1:1

The ratio of parent to daughter after one half-life will be 1:1. After two half-lives half of the remaining half will decay leaving one-quarter of the original radioactive parent atoms. Those transformed atoms bring the tally of daughter atoms to three-quarters of the crop of parent plus daughter atoms.

## When should a long half-life versus a short half-life isotope be used for dating?

Radioisotopes with longer half-lives are used **to date older specimens** and those with shorter half-lives are used to date younger ones. Carbon-14 dating is used to date specimens younger than about 60 000 years old. It is commonly used to date fossils of living things and human artifacts.

## What is the easiest way to calculate half-life?

## What is a half-life in math?

**the amount of time it takes a given quantity to decrease to half of its initial value**. The term is most commonly used in relation to atoms undergoing radioactive decay but can be used to describe other types of decay whether exponential or not.

## How do you solve half-life problems on a calculator?

## How do you calculate half-life in college algebra?

## What isotope has the shortest half-life?

**Hydrogen-7** ( about 23x10E-24) has the shortest half life.

## Ex: Exponential Model – Determine Age Using Carbon-14 Given Half Life

## Half-Life Calculations: Radioactive Decay

## Half Life Chemistry Problems – Nuclear Radioactive Decay Calculations Practice Examples

## A radioactive isotope has a half -life of 1.2 billion years . As measured by the presence of the