Question

PLEASE HELP
Complete and balance an equation for each reaction
b. Al + Cl2

Now, I have the solution that the teacher provided us, in order to study for the exam; however, I cannot for the life of me seem to make sense of it.

The solution is 2Al + 3Cl2 -> 2AlCl3

The part I am deeply confused on is: why the heck does Al+Cl2 turn into 2Al + 3CI2, where do that 2 and 3 come from????

Answer 1

See, when \(Al\) and \(Cl_2\) combine, they form \(AlCl_3\)

Answer 2

So, I can write that as :

\(Al + Cl_2 \rightarrow AlCl_3\)

You can notice in RHS , we have 3 Cl atoms and 1 Al atom

In LHS, We have only 2 Cl atoms and 1 Al atom.

Answer 3

So, in order to balance it, we put some numbers behind them so that the equation can be balanced.

Answer 4

oh, ok well I understand that part because Al and Cl are being multiplied therefore you would just add the subscript.

Answer 5

No.. its not like that

Answer 6

Al is Aluminium Atom
Cl is Chlorine Atom

Now see, Al is combined (added) to Chlorine gas (\(Cl_2\) ) and then a product is formed.

It is like a chemical reaction, just like while cooking you add something to another thing and a third thing is formed

Answer 7

But remember, while cooking you use those two things (call them as reactants) in a proper ratio like 1 Tea spoon etc. to get a proper third thing (call it as product)

Similar is the case in Chemistry. When you react Aluminium with Chlorine Gas (\(Cl_2\)) then \(AlCl_3\) is formed. (AlCl3 is also called as Aluminium Tri Chloride)

Answer 8

I didn't understand that at all. you see i thought of it mathwise, because I know that in math when you multiply a variable with another variable and you have exponents then you would simply add the exponents...

Answer 9

There is no specific method to know what will be formed though you can know it like :

Al has valency of +3 (that is it can lose 3 electrons with another element)
Cl has valency of -1 (that is it can gain 1 electron from another element)

So, Al (+3) and Cl (-1) when combine it becomes

Answer 10

Im sure your teacher provides you a periodic table on your test and quizes correct?

Answer 11

...well I atleast understood the rest. Because, after you have Al + Cl2 -> AlCl3
On the left side I have Al: 1 Cl: 2, and then on the right side I have Al 1 CI:3 so the Al is already balanced. But then we need to balance Cl, so it is Al + 1 1/2 Cl2 -> AlCl3, however we cannot have a fraction therefore we multiply it by 2, and then we have 2Al + 3 CI2 -> 2 AICI3 right? And, we can use thee periodic table, but all I understand on it are the symbols, and the atomic mass. I have no idea how it'll help me with electrons.

Answer 12

how would I go about using the periodic table for this though? Because, as you can see I get stuck on that first part, but then I can balance the equations pretty easily.

Answer 13

Look at that photo

Answer 14

As you can see Al is located under +3 and Cl is located under -1

Answer 15

ah, I never even knew of that my teacher can't teach for the world and I can usually teach myself pretty quick except that wasn't in my sucky textbook either. this makes so much more sense now

Answer 16

Check out the diagram I drew above.

Answer 17

yah, I know I saw except I didn't understand at all until now because I didn't know where those numbers had come from.

Answer 18

The last part of balancing is simple\[Al+Cl _{2}\rightarrow AlCl _{3}\] All you need to do is make sure you have the same number of each substance on both sides.

Answer 19

\[2Al+3Cl _{2}\rightarrow 2AlCl _{3}\]

Answer 20

Basically the coefficent distributes to all of the Substances

Answer 21

So the 3 in front of the Cl2 makes it a 6 and the 2 in front of AlCl3 distributes to Al and Cl and since Cl has a subscript of 3 on the right side it becomes a 6 also

Answer 22

Sorry if this is a bit confusing

Answer 23

If you just look at the final answer you will see that on both sides we have the same number of each substance.