Beryllium is a chemical element with symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays.

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2 years ago

Which of the following are considered pure substances?

Tanzania [10]

Element. Everything is else is a mixture, therefore not pure.

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3 years ago

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The element californium (cf) sells for $1000 per µg. assuming 6.02 x 1023 atoms of cf have a mass of 251 grams, how many atoms o

saveliy_v [14]

Answer:- $2.40*10^1^0atoms$

Solution:- It is a simple unit conversion problem. We could solve this using dimensional analysis.

We know that, 1 US dollar = 100 cents

1 cent = 1 US penny

So, 1 US dollar = 100 US pennies

$1g=10^6\mu g$

Let's make the set up starting with 1 penny as:

$1penny(\frac{$1}{100pennies})(\frac{1\mu g}{$1000})(\frac{1g}{10^6\mu g})(\frac{6.02*10^2^3atoms}{251g})$

= $2.40*10^1^0atoms$

Therefore, we can bye $2.40*10^1^0atoms$ of Cf in one US penny.

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2 years ago