Name: __________________________
Class: _________
Radiometric Dating Homework
Directions: For the questions below, please show your work and include units on your
answers!!!
1. Carbon 14 (C-14) decays into Nitrogen (N-14) with a half-life of 5,730 years. A
fossilized bone was found to contain 0.281 g of C-14 and 17.719 g of N-14. How old is
the bone?
2. Potassium decays into Argon with a half-life of 1.3 billion years. A fossil sample
found contains 5.75 g Potassium and 17.25 g Argon. How old is the fossil sample?
3. Rubidium decays into Strontium and has a half-life of about 49 million years. If a
scientist finds a bone that contains 0.438 g of Rubidium and 6.562 g of Strontium,
how old is the bone?
4. A chunk of amber (hardened tree sap) containing a fossilized insect is found. After
running C-14 dating tests, scientists determine it contains 2.11 g of C-14 and 87.89 g
of Nitrogen. Carbon has a half-life of 5,730 years. How old is the insect?
5. Scientists on an excursion in Africa found a rock, and want to determine how old it
is. The rock has 6 g of Rb-87 and 10 g of Sr-87. Rubidium decays into Strontium and
has a half-life of about 49 million years. How old is the rock?
6. A rock that contains fossils has 15 g of Uranium 238 (U-238) and 5 g of Lead (Pb206). Scientists assume that the fossils are the same age as the rock. If Uranium
238 decays into Lead with a half-life of 4.5 billion years, how old are the fossils?