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Answer:
C. The half-life of C-14 is about 40,000 years.
Explanation:
The only false statement from the options is that the half-life of C-14 is 40,000yrs.
The half-life of an isotope is the time it takes for half of a radioactive material to decay to half of its original amount. C-14 has an half-life of 5730yrs. This implies that during every 5730yrs, C-14 will reduce to half of its initial amount.
- All living organisms contain both stable C-12 and the unstable isotope of C-14
- The lower the C-14 compared to the C-12 ratio in an organism, the older it is.
Answer:
4.20 moles NF₃
Explanation:
To convert between moles of N₂ and NF₃, you need to use the mole-to-mole ratio from the balanced equation. This ratio consists of the coefficients of both molecules from the balanced equation. The molecule you are converting from (N₂) should be in the denominator of the ratio because this allows for the cancellation of units. The final answer should have 3 sig figs because the given value (2.10 moles) has 3 sig figs.
1 N₂ + 3 F₂ ---> 2 NF₃
2.10 moles N₂ 2 moles NF₃
--------------------- x --------------------- = 4.20 moles NF₃
1 mole N₂
The concept that this best illustrates is replication.
