Radioactive elements decay at a know rate known as half-life. Choose all of the correct statements concerning half-life. Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years. Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years. Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years. Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams. Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years.

Explanation:

Half life is simply the amount of time it takes for half of a substance to decompose.

Options;

- Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years. This is incorrect. After 5730 years, 15g of the sample ought to remain.

- Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years. This is correct. 3 * 76000 = 228,000

- Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years. This is incorrect. Mass after 3 half lives (27/9) = 9.5 (38 / 2 / 2)

- Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams. This is incorrect. Mass after 4 half lives (6 / 1.5) = 2.5 gram (40 / 2 / 2 /2 / 2)

- Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years. This is incorrect. Original sampe = 240 gram. So after 2 half lives (105,000/52500), mass left = 60 (240 / 2 /2)

the answer is: they rebelled against saddam hussein’s rule.

kurds opposed saddam rule and wanted independence. kurds in the north and shiites in the south revolt against hussein.

for example, the halabja attack in 1988 conducted against the kurdish people by the iraqi regime under saddam hussein, where between 4000 people are killed and around 9000 are injured.

is there multiple choice answers?