B) An unknown radioactive substance has a half-life of 3.20 hours. If 47.3 g of the substance is currently present, what mass A0 was present 8.00 hours ago?
Express your answer with the appropriate units.
C) Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 30.0 % of an Am-241 sample to decay?
Express your answer with the appropriate units.
D) A fossil was analyzed and determined to have a carbon-14 level that is 50 % that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?
Express your answer with the appropriate units.
B) An unknown radioactive substance has a half-life of 3.20 hours. If 47.3 g of the...
An unknown radioactive substance has a half-life of 3.20 hours. If 39.6 g of the substance is currently present, what mass Ao was present 8.00 hours ago? Express your answer with the appropriate units. View Available Hint(s) ? OP HÅR A9 = Value O 2 Units Submit Part C Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0 % of an Am-241...
a) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 76.2 minutes , what is the half-life of this substance? b)An unknown radioactive substance has a half-life of 3.20 hours . If 14.6 g of the substance is currently present, what mass A0 was present 8.00 hours ago? c) Americium-241 is used in some smoke detectors. It...
In the parts that follow, use the following abbreviations for time: Measure of time Units of time minutes min hours h days d years yr a) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 93.0 minutes , what is the half-life of this substance? Express your answer with the appropriate units. t(1/2) = ______ b) An...
A) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 48.2 minutes , what is the half-life of this substance? B) An unknown radioactive substance has a half-life of 3.20 hours . If 24.3 g of the substance is currently present, what mass A0 was present 8.00 hours ago? C) Americium-241 is used in some smoke detectors....
An unknown radioactive substance has a half-life of 3.20 hours . If 23.9 g of the substance is currently present, what mass Ao was present 8.00 hours ago? Express your answer with the appropriate units. ► View Available Hint(s) ? Å Value o O Units A0 = Phosgene (carbonyl chloride), COCl2, is an extremely toxic gas that is used in manufacturing certain dyes and plastics. Phosgene can be produced by reacting carbon monoxide and chlorine gas at high temperatures: CO(g)...
An unknown radioactive substance has a half-life of 3.20hours . If 30.7g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your answer with the appropriate units.
Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 32.0 % of an Am-241 sample to decay? Express your answer numerically in years.
Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 44.0 % of an Am-241 sample to decay?
Review | Constants Periodic Table In the parts that follow, use the following abbreviations for time If a substance is radioactive, this means that the nucleus is unstable and will therefore decay by any number of processes (alpha decay, beta decay, etc.). The decay of radioactive elements follows first-order kinetics. Therefore, the rate of decay can be described by the same integrated rate equations and half-life equations that are used to describe the rate of first-order chemical reactions: Measure of...
Americium-240 has a half-life of 2.12 days. (Can you see why americium-241 is used in smoke detectors rather than americium-240? See exercise 4.) How many hours does it take for 34.5% of a sample of americium-240 to decay? answer should be 31.1 hr