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34kurt
1 year ago
13

Radioactive phosphorus-32 decays with a half-life of 14.0 days. A chemist obtains a fresh sample of phosphorus-32 and measures i

ts radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How many days does she have to perform the experiment
Chemistry
1 answer:
solniwko [45]1 year ago
3 0

It will take 28 days to let the radioactivity fall below 25%.

<h3>What is Half Life ?</h3>

Half life can be described as the time required by the radioactive compound to reduce to half of the original value of concentration.

It is given that

Radioactive phosphorus-32 decays with a half-life of 14.0 days

25% of the initial measure at what time =?

For 50% decay the time needed is 14 days

for decay of the next 50%  of the amount left the time taken will be another 14 days

2nd half life = 25% decay of the substance = 28 days

Therefore it will take 28 days to let the radioactivity fall below 25%.

To know more about Half Life

brainly.com/question/24710827

#SPJ1

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Have people considered that aliens could possibly live without oxygen and water and we are looking in the wrong direction for a
bija089 [108]
I have never heard anyone ever say anything about aliens only living by using the same metabolistic processes as humans... But.. there may likely be another planet out there that does use oxygen, although at a different percentage from Earths. Anyways, even if we do find "other" life forms, who's to say that they're on the same level as us? Have you ever considered the fact that ants to us are like we are to other life forms out there and maybe they don't want or can't communicate with us because they see themselves as superior?

Hope that helps!
8 0
3 years ago
Explain how you determine the freezing point of a solution that does not have a well-defined transition in the cooling curve.
Sophie [7]

This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.

The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.

However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.

As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:

y=-3.5 x + 25\\\\y=-0.52 x + 2

First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:

-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72

Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:

y=-3.5 (7.72) + 25\\\\y = 1.84

This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.

Learn more:

  • brainly.com/question/22818252
  • brainly.com/question/9680530

7 0
2 years ago
Please help!!!!!!!!!!!!!!!
svlad2 [7]
The 2nd one is the right answer

Hope this helped
3 0
2 years ago
43 mg = [?]g <br>A. 0.043 g <br>B. 4.3 g <br>C. 4300 g <br>D. 43,000 g​
Ymorist [56]

Answer:

Option A (0.043 g) is the correct answer.

Explanation:

Given:

= 43 mg

As we know,

1 \ mg = \frac{1}{1000} \ g

then,

⇒ 43 \ mg = \frac{43}{1000}  \ g

              = 0.043 \ g

Thus, the above is the correct alternative.

4 0
2 years ago
Urgent! <br> which element do you think has a greater mass? cadmium or zinc?
Alex Ar [27]

Answer:

zinc

Explanation:

5 0
2 years ago
Read 2 more answers
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