Question

What is the mass in grams of a single atom of each of
the following elements? (a) As, (b) Ni.
please explain..

Answer 1

Here's a question to test your understanding of the concept of a mole of an element or a compound. 1 mole is an expression of the atomic or molecular weight of an element or compound in grams, so for arsenic it's 75 and for nickel it's 58.7. The other thing you need to know is the constant known as Avogadro's number - this is how many atoms make up 75g of arsenic or 58.7g of nickel. The value is 6.022e23, so if you divide 75 by this constant you'll know how much one atom weighs in grams.