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Questions and Answers
Explain the difference between an isotope and a radioisotope.
Explain the difference between an isotope and a radioisotope.
An isotope is an atom of an element with the same number of protons but a different number of neutrons. A radioisotope is an isotope that is radioactive.
Calculation the value of a 100g sample of a radioactive substance has a half-life of 5 years. How much of the substance remains radioactive after 15 years? Answer: 12.5g
Calculation the value of a 100g sample of a radioactive substance has a half-life of 5 years. How much of the substance remains radioactive after 15 years? Answer: 12.5g
12.5g
What is the time it takes for half of a radioactive sample to decay?
What is the time it takes for half of a radioactive sample to decay?
Half-life
The original radioactive material before decay.
The original radioactive material before decay.
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The stable material formed after radioactive decay.
The stable material formed after radioactive decay.
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A type of radioactive decay where an alpha particle is emitted, reducing the atomic number by 2 and mass number by 4.
A type of radioactive decay where an alpha particle is emitted, reducing the atomic number by 2 and mass number by 4.
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After 2 trials in the M&M lab, 25 M&M's remain. If each trial represents one half-life, how many M&M's would be present after 5 half-lives?
After 2 trials in the M&M lab, 25 M&M's remain. If each trial represents one half-life, how many M&M's would be present after 5 half-lives?
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Explain this graph.
Explain this graph.
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Based on the graph estimate the half-life of Mercury 203.
Based on the graph estimate the half-life of Mercury 203.
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If each trial represents 4.2 years, what is the half-life of the red M&M's?
If each trial represents 4.2 years, what is the half-life of the red M&M's?
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Suppose you start with 100 grams of red M&M's. How much remains after 12.6 years? Answer: 5 grams.
Suppose you start with 100 grams of red M&M's. How much remains after 12.6 years? Answer: 5 grams.
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Describe the relationship between the parent material and the daughter material over time. Answer: As the parent material decreases due to radioactive decay, the daughter material increases proportionally.
Describe the relationship between the parent material and the daughter material over time. Answer: As the parent material decreases due to radioactive decay, the daughter material increases proportionally.
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The half-life of radium-222 is 38 seconds. If you have a 12-gram sample, how much remains after 114 seconds? Answer: 1.5 grams.
The half-life of radium-222 is 38 seconds. If you have a 12-gram sample, how much remains after 114 seconds? Answer: 1.5 grams.
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Matter cannot be created or destroyed in a chemical reaction. Therefore, the number of each type of atom must be the same on both sides of a chemical equation.
Matter cannot be created or destroyed in a chemical reaction. Therefore, the number of each type of atom must be the same on both sides of a chemical equation.
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Substances on the left side of the equation are reactants, and those on the right side are products.
Substances on the left side of the equation are reactants, and those on the right side are products.
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Numbers placed before compounds to balance the equation.
Numbers placed before compounds to balance the equation.
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Elements that exist as two atoms bonded together in their natural form (e.g., H2, O2, N2).
Elements that exist as two atoms bonded together in their natural form (e.g., H2, O2, N2).
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Compounds composed of two different elements (e.g., NaCl, H2O).
Compounds composed of two different elements (e.g., NaCl, H2O).
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Write the unbalanced equation.
Write the unbalanced equation.
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Count the number of atoms of each element on both sides.
Count the number of atoms of each element on both sides.
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Study Notes
Radioactive Decay and Half-Life
- Half-life: The time it takes for half of a radioactive sample to decay.
- Radioactive Decay: Decay where an unstable atomic nucleus loses energy by emitting particles.
- Parent Material: The original radioactive substance.
- Daughter Material: The stable substance formed by the decay.
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Alpha Decay: A type of radioactive decay where an alpha particle (a helium nucleus) is emitted.
- This reduces the atomic number by 2.
- This reduces the mass number by 4.
Radioactive Decay Calculations
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Example: A 100g sample of a radioactive substance with a 5-year half-life.
- After 5 years, 50g remains radioactive.
- After 10 years, 25g remains radioactive.
- After 15 years, 12.5g remains radioactive.
Isotopes and Radioisotopes
- Isotopes: Atoms of the same element with different numbers of neutrons.
- Radioisotopes: Isotopes that are radioactive.
Graphing Radioactive Decay
- Graphs of radioactive decay show an exponential decrease in the amount of radioactive material over time.
M&M Example
- Half-life: 4.2 years based on given experiment data.
- Starting Quantity: 100 grams of M&M's
- Remaining after 12.6 years: 5 grams
Chemical Equations
Balancing Equations
- Law of Conservation of Mass: Matter cannot be created or destroyed in a chemical reaction.
- The number of each type of atom is the same on both sides of a balanced chemical equation.
- Reactants: Substances on the left side of the equation.
- Products: Substances on the right side of the equation.
- Coefficients: Numbers placed before compounds to balance the equation.
Diatomic Molecules
- Elements that exist as two atoms bonded together in their natural form (example: H2, O2, N2).
Binary Compounds
- Compounds composed of two different elements (example: NaCl, H2O).
Steps to Balance Equations
- Write the unbalanced equation.
- Count the number of atoms of each element on both sides.
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Description
Test your knowledge on radioactive decay and half-life concepts. This quiz covers terms such as isotopes, radioisotopes, and calculations related to half-lives. Challenge yourself with questions on alpha decay and graphing radioactive decay.