Question
25. The half-life for a 100-gram sample of radioactive element X is 5 days. How much of element X remains after 10 days have passed?
a
10o g - no change
b
25 g
c
50 g
d
12.5 g
26. What happens to the volume of a gas when the temperature is decreased?
a
The volume increases.
b
The mass decreases.
c
The volume decreases.
d
The pressure increases.
a
10o g - no change
b
25 g
c
50 g
d
12.5 g
26. What happens to the volume of a gas when the temperature is decreased?
a
The volume increases.
b
The mass decreases.
c
The volume decreases.
d
The pressure increases.
Answers
GPT-4o mini
25. To determine how much of radioactive element X remains after 10 days, we can use the concept of half-lives. The half-life is the time it takes for half of the substance to decay.
1. After the first half-life of 5 days, 50 grams of element X remains (half of 100 grams).
2. After the second half-life (5 more days, totaling 10 days), half of the remaining 50 grams will remain, which is 25 grams.
So, the answer is **b) 25 g**.
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26. According to Charles's law, when the temperature of a gas decreases, the volume also decreases, assuming pressure remains constant.
So, the answer is **c) The volume decreases.**
1. After the first half-life of 5 days, 50 grams of element X remains (half of 100 grams).
2. After the second half-life (5 more days, totaling 10 days), half of the remaining 50 grams will remain, which is 25 grams.
So, the answer is **b) 25 g**.
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26. According to Charles's law, when the temperature of a gas decreases, the volume also decreases, assuming pressure remains constant.
So, the answer is **c) The volume decreases.**