SOLUTION: a uranium atom has a mass of 3.95 x 10^-22 grams. A sample of uranium has a mass of 9.085 x 10^-1 grams. Determine how many atoms are in the sample using scientific notation ple

Question 1204549: a uranium atom has a mass of 3.95 x 10^-22 grams. A sample of uranium has a mass of 9.085 x 10^-1 grams. Determine how many atoms are in the sample using scientific notation
please help I have a math test tomorrow
Found 2 solutions by math_tutor2020, josgarithmetic:
Answer by math_tutor2020(3817) (Show Source): You can put this solution on YOUR website!

For the sake of a simple example, let's say that one single atom of uranium has a mass of 2 grams.
Of course this is way too large but it's for illustrative purposes only.

If we had a sample of 12 grams of uranium total, then we'd have 12/2 = 6 atoms.

Or in terms of algebra
2n = 12
n = 12/2
n = 6

-------------------------------------

Let's return back to real-world figures now.

We'll have n still represent the number of atoms.

We multiply this value n with the mass of one atom of uranium.
The expression (3.95x10^(-22))*n represents the total amount of mass, when we have n atoms of uranium.
The x refers to multiplication and it's not a variable.

Set this equal to the stated total amount 9.085x10^(-1) and let's isolate n.
(3.95x10^(-22))*n = 9.085x10^(-1)
n = 9.085x10^(-1) divide (3.95x10^(-22))
n = (9.085/3.95) x 10^(-1 - (-22) )
n = 2.3 x 10^21

This number is really massive. We write 23 and then have 20 zeros after the number.
The massive number is: n = 2,300,000,000,000,000,000,000
I started with 2.3 and then moved the decimal point 21 spots to the right to arrive at the large number shown above.

Scientific notation is best suited for massive numbers like this.

Answer: 2.3 x 10^21 atoms

Answer by josgarithmetic(39630) (Show Source): You can put this solution on YOUR website!
Number of atoms per gram

Sample of grams uranium

2.30*10^21 atoms

The given information limits to number to three significant figures.
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