A substance has a half-life of 100,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance’s parent material is left? (2 points)

The graph below shows the radioactive decay of an isotope of carbon. Based on the graph, what is the half-life of carbon? (4 points)

Which of the following reduces the number of protons in the nucleus of an atom by 2? (2 points)

A rubidium isotope has a half-life of almost 50 billion years. Given that scientists estimate Earth’s age to be 4.6 billion years, what is the most likely percentage of parent to daughter isotopes of this element currently existing on Earth? (2 points)

The Dead Sea is a location where high evaporation rates occur. What can you conclude about the water in the Dead Sea? (2 points)

A substance has a half-life of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance’s parent material is left? (2 points)

Scientists estimate Earth’s age to be 4.6 billion years. Samarium has a half-life of approximately 106 billion years. From the present date, approximately how many more years must pass before a sample of samarium that was created at the beginning of Earth’s history contains 25 percent of the original parent material? (2 points)

The half-life of carbon-14 is 5,730 years. How many grams of parent material will remain from a 120-gram sample of carbon-14 after 2 half-lives? (2 points)

Carbon-14 has a half-life of approximately 5,730 years. How many half-lives have occurred in a sample that contains 25 percent of the original amount of the parent isotope? (2 points)

The following graph shows the rates of decay for four parent isotopes. Based on the graph, which parent isotope most likely has a half-life of 4.5 billion years? (2 points) Public Domain