Question

If the original mass of the radioactive material was 500 grams, what will be its mass after 4 billion years?

10.25 grams
12.50 grams
25.50 grams
31.25 grams

Answer 1

@genius12 I really need your help!!!

Answer 2

@genius12

Answer 3

@genius12

Answer 4

@genius12

Answer 5

@superhelp101 Sorry I was gone. Are you still here?

Answer 6

o yes I am here! :)

Answer 7

Hello?? are u there?

Answer 8

From the graph it seems to be that the material reaches 25% its original mass after 2 billion years. Plugging these values in to the half life formula we get:\[\bf 0.25(500 )=500 (0.5)^{\frac{2 \ BY}{h}} \implies \frac{125}{500}=(0.5)^{\frac{2 \ BY}{h}}\]\[\bf \implies \log \left( \frac{ 125 }{ 500 } \right)=\frac{ 2 \ BY }{ h } \log(0.5) \implies h = \frac{ 2 \ BY (\log(0.5)) }{ \log \left( \frac{ 125 }{ 500 } \right) }=1 \ BY\]And 'BY' is short for 'Billion Years'. So the half life of the substance shown is about 2 BY. From this, we can find it's mass after 4 billion years which can still be approximated by looking at the graph but will be a better approximation if we use the information we were able to find so far. Using the formula again, let's find the final mass 'A' from the initial mass 500g, the half life being approximately 2 BY and the time taken to decay being 4 BY:\[\large \bf A=500(0.5)^{\frac{4 \ \cancel{BY}}{1 \ \cancel{BY}}}=500(0.5)^4=31.25 \ g\]And that's our final answer. Now you easy, my entire answer was based on a careful observation from the graph which was that it takes 2 BY for the substance to reach 25% the original amount. Based on that approximate observation of the graph, I was able to derive the following results. This shows that if you read the graph carefully, you can figure these things out yourself.

Answer 9

@superhelp101

Answer 10

@superhelp101 Do you understand?

Answer 11

Wow now I get it!!!

Answer 12

Thank you!!!!!!!!!

Answer 13

Can you help me with another please:


The table below compares the radioactive decay rates of two materials.

Material Original mass of material (in grams) Mass of material after 21.6 seconds (in grams)
1 100 12.5
2 200 25
Based on the table, which of these conclusions is most likely correct?

The half-life of Material 1 and Material 2 are equal.
The half-life of Material 2 is double the half-life of Material 1.
The half-life of Material 2 is 10.8 seconds more than the half-life of Material 1.
The half-life of Material 1 is 10.8 seconds more than the half-life of Material 2.
@genius12

Answer 14

@superhelp101 I've showed you step by step on how to approach similar problems and you can also look at the problem I assisted watermelon with. From the knowledge you've gained, first attempt the question by yourself and if there is still something you can't understand then tag me and I'll drop by.

Answer 15

Okay thanks!

Answer 16

I checked watermelon's but I still don't understand is there a way you can explain it to me the same way you did at the beginning? That beginning one was really helpful and I understood the process very well!

Answer 17

@genius12

Answer 18

@genius12

Answer 19

Note that material 1 is at 100g and after 21.6 sec its 12.5 g. Material 2 is 200g and after 21.6 sec its 25g. Both materials are now at 1/8 the original mass after THE SAME PERIOD OF TIME. This must mean that they decay at the same rate hence both materials have an equal half life. @superhelp101

Answer 20

Thank you so much you are like heaven I understand it!!! Can you help me with another:

One group of students did an experiment to study the movement of ocean water. The steps of the experiment are listed below.
Fill a rectangular baking glass dish with water.
Place a plastic bag with ice in the water near the left edge of the dish.
Place a lighted lamp near the left edge of the dish so that its light falls directly on the plastic bag.
Put a few drops of ink in the water.
The student did not observe any circulation of ink in the water as expected because the experiment had a flaw. Which of these statements best describes the flaw in the experiment?

Not enough ink was added.
Not enough water was taken.
The dish was too small for the experiment.
The lamp and the ice bag were at the same place.
@genius12

Answer 21

@superhelp101 Now I'm sure after the questions we've done together so far, you can atleast attempt this one yourself =P

Answer 22

I said A, but just to make sure!

Answer 23

Just to see if you agree with A

Answer 24

@genius12

Answer 25

Do you agree with A? @genius12

Answer 26

@superhelp101 Yes I believe so.

Answer 27

Thanks!!! :-)

Answer 28

I just need one more help!:

Which of these labels best fits the empty cell in the diagram?

Creation of living virus molecules from plants
Splitting up of molecules to form simple structures
Reaction between non-living and living molecules
Combining of molecules to form complex structures

I probably think D on this but not too sure! And you were a big help to me to thanks!
@genius12

Answer 29

@genius12 you still there? :(

Answer 30

@genius12