How many uranium atoms are there in 7.1 g
of pure uranium? The mass of one uranium
atom is 4 × 10^−26kg.

Question

How many uranium atoms are there in 7.1 g
of pure uranium? The mass of one uranium
atom is 4 × 10^−26kg.

anonymous · Answer

using your info:$$7.1g\frac{1 atom}{4x10^{-26}kg}\frac{1 kg}{1000 g}$$

anonymous · Answer

Still confused... what am I supposed to do with that?

anonymous · Answer

They are conversion units... if the units cancel, you usually get the right answer, but it tells you how to multiply or divide to get the answer (if the units work out).  If you look at it... kg cancels with kg and g cancels with g... leaving atoms in the numerator.  To get the number... take 7.1 divided by 4x10^-26 then divide again by 1000.

anonymous · Answer

ohhh okay that makes sense! thanks

anonymous · Answer

You're welcome.  :)