Potassium-40 has a half-life of 1.277 mc013-1.jpg 109 years. after 1.022 mc013-2.jpg1010 years, how much potassium-40 will remain from a 500.3-g sample? approximately 1.95 g approximately 3.91 g approximately 62.54 g approximately 71.47 g

The correct answer is approximately 1.95g. First, take (1.022*10^10)/(1.277*10^9). This is the same as time elapsed/half-life. This gives you 8, which is the number of half lives. Then multiply mass (500.3g) by (1/2)^8, resulting in 1.95g, which is the answer.

The metal is named first