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What is the mass in grams of #2.10 * 10^21# atoms of copper, #Cu#?

Answer 1

Olivia Anton

There are #N_A# individual copper atoms in a moles of copper metal, and this has a mass of #63.55# #g#.

So we know that #"Avogadro's number"(N_A)# of individual copper atoms have a mass of #63.55# #g#.

Thus #(2.10xx10^21"copper atoms"xx63.55*g*mol^-1)/(6.022140857(74)×10^23 "copper atoms " mol^-1)# #=# #??g#

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Answer 2

Jeremiah Adams

Copper (Cu) has a molar mass of about 63.55 g/mol. Based on Avogadro's number (6.022 x 10^23 atoms/mol), 2.10 * 10^21 atoms of copper have a mass of about 0.220 grams.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.