Question

Ok, I'm stuck on another question that my book isn't fully explaining to me.

In the formula 5CaSO4 the total number of sulfur
atoms present is
a. 1.
b. 5.
c. 9.
d. 20.


now, how can I tell the number of the sulfur in the first place? (sorry im not good at this at all)

Answer 1

Treat it like a math problem.

If you had \(5(x+2y+4z)\), you would have 5x, 10y, 20z

Answer 2

alright....

Answer 3

\(5(Ca+S+4O) \)

Answer 4

alright, forgive me if im wrong, (just trying to understand this) but the correct answer would be.... 20?

Answer 5

no remember sulfur is S,

So from \(5(Ca+S+4O)=5~ Ca+5~S+20 ~O\)

Answer 6

im completely lost. I'm sorry for being a bother :/

Answer 7

Look at it this way: if there was only one CaSO4, there would be 1 Ca, 1 S, and 4 O, right?

Answer 8

yes

Answer 9

But there's five CaSO4. That means that there's five times as many of each of the elements within it, correct?

Answer 10

^yep. forget the 5 in the front. That is only multiplying the whole unit.

this is 1 of the units

Answer 11

So, knowing that, how many sulfur atoms would you say are in the molecule?

Answer 12

1!

Answer 13

Ah, no, that's how many there is in ONE CaSO4 molecule.

Answer 14

There's five- so then, 5 x 1 would be...

Answer 15

nonono

Answer 16

sorry i just discovered how you guys are trying to get me to reason on this (thnak you)

Answer 17

the answer is 5 because you said that the sulfer molecule equals 1, jujst like the calcium. And the 4 is showing that the oxygen has 4 atoms. because theres no extra number for the sulfur or calcium, we assume that they have only one

Answer 18

and then 1, times 5, equals 5, is that right?

Answer 19

pretty much

Answer 20

thank you guys!

Answer 21

sorry that i wasn't getting it. thank you for reasoning on it with me.

Answer 22

no problem, +1 for teamwork.

if you have more problems like these, try drawing the structure out first

Answer 23

Have you learnt Lewis or Bohr structures yet though?

Answer 24

no. i have not

Answer 25

Don't worry about it then, you'll learn it soon enough if you're in Chem.

Answer 26

alright, thanks ^-^