Question

●
What is the mass of 7.50x1023 molecules of CaCl₂?

Answer 1

138.22 g

Step-by-step explanation:

First, determine the molecular weight of
`CaCl_2`:

M.W. Ca = 40.08
`(g)/(mol)`

M.W. Cl = 35.45
`(g)/(mol)`

So,

M.W.
`CaCl_2=(40.08(g)/(mol))+2(35.45(g)/(mol))`

M.W.
`CaCl_2=40.08(g)/(mol)+70.90(g)/(mol)`

M.W.
`CaCl_2=110.98(g)/(mol)`

Recall that one mole of anything is equal to
`6.022x10^(23)` of that thing (as one dozen is equal to 12).

So,

`7.50x10^(23) moleculesCaCl_2((1mol)/(6.022x10^(23)molecules))=1.25molCaCl_2`

Next, determine the mass:

`1.25molCaCl_2((110.98g)/(1mol))=138.22gCaCl_2`