Question #7504a

1 Answer
Dec 10, 2015

Answer:

Here's what I got.

Explanation:

You're actually dealing with a coordination compound called hexamminechromium(III) nitrate, which consists of the hexaamminechromium(III) complex ion, #"Cr"("NH"_3)_6^(3+)#, and the nitrate anion, #"NO"_3^(-)#.

More specifically, the coordination compound consists of one hexamminechromium(III) complex ion and three nitrate anions.

So, how many elements are a part of this compound? To figure that out, break up the complex ion and the nitrate anion into their respective constituent elements.

Notice that #6# subscript that follows the ammonia ligands. This means that the complex ion contains six ammonia molecules, #"NH"_3#, so make sure that you keep track of all these atoms.

You can thus say that #"Cr"("NH"_3)_6^(3+)# contains

  • one chromium atom, #"Cr"#
  • six nitrogen atoms, #"N"#
  • eighteen hydrogen atoms, #"H"#

Now focus on the nitrate anion. Notice that it has a #3# subscript, so keep that in mind when listing the number of atoms it contains.

You can say that three nitrate anions, #3 xx"NO"_3^(-)#, will contain

  • three nitrogen atoms, #"N"#
  • nine oxygen atoms, #"O"#

So, this coordination compound contains four distinct elements

  • chromium
  • hydrogen
  • nitrogen
  • oxygen

Add up all the atoms we've listed above to get the total number of atoms per element

  • chromium: #1 -># from the complex ion
  • hydrogen: #18 -># all from the complex ion
  • nitrogen: #9 -># #6# from the complex ion and #3# from the three nitrate anions
  • oxygen: #9 -># all from the nitrate anions

The total number of atoms present in the compound will be

#"no. of atoms" = 1 + 18 + 9 + 9 = 37#