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Question 14 0 / 7 points a) Fill in the missing number of protons and neutrons in the beta decay shown.(2 marks) 15 P (-) 17 N Beta Particle b) A sample of carbon-14 has a mass of 2.0 x 10- g. Carbon-14 has a half-life of 6000 years. How much carbon-14 will be left after 24 000 years? (3 marks) c) Why can carbon-14 be used to date things that have died, but not to date rocks that formed many millions of years ago? Give two reasons. (2 marks) - No text entered - This question has not been graded. The correct answer is not displayed for Written Response type questions. Hide question 14 feedback a) 16 protons and 16 neutrons b) At t = 0, the mass is 2.0 x 10- g At t = 6000 years, the mass is 2.0 x 10 6 g x 1 = 1.0 x 10-6 g At t = 12 000 years, the mass is 1.0 x 10- g x 1 = 5.0 * 10 7g At t = 18 000 years, the mass is 5.0 x 107 g x 1 = 2.5 x 10-7g At t = 24 000 years, the mass is 2.5 x 10 0 g x 1 = 1.25 x 10-7 g c) This Carbon-14 is not absorbed and stored in rock in any predictable way, so there is no way to estimate how much would have initially been contained in the rock, if any. Carbon-14 is stored in living things while they are alive, and the proportion of Carbon-14 is the same when they die. The half-life of Carbon-14 is too short to be used to estimate the age of ancient rocks, as it would decrease to very small, undetectable levels within the time periods that measure geologic changes in the earth