how can i work out to find the correct answer ? can you please explain

Question

According to the following reaction, how many grams of bromine will be formed upon the complete reaction of 30.1 grams of bromine trifluoride?

bromine trifluoride (g) bromine (g) + fluorine (g)

Answer 1

Hey Hawwa,

 

It looks like to be like this:

 

Br + F --->   BrF₃

 

To balance the equation, it will look like this:

 

Br + 3F  --->  BrF₃

 

You can see that from 2nd equation, there is 1 Br, 3F, and 1 BrF₃.  In other words, 1 mol of Br, 3 mol of F, and 1 mol of BrF₃.  Since both Br and BrF₃ has 1 mol (each), the ratio will be 1:1.

 

Here is how to get it (use Stoichiometry):

                                                     

Br = 79.9 g  F = 19.0 g   

 

            Br           F₃

BrF₃ = 79.9 + 19.0 * 3 = 79.9 + 57.0 = 136.9 grams / 1 mol

 

 

30.1 g (BrF₃)          1 mol                79.9 g (Br)

------------------ x  ------------------- x --------------   =   17.5675 g   

                          136.9 g (BrF₃)         1 mol

 

 

 

= 17.6 grams of Br (for 3-sig figs)

 

 

From 30.1 grams of BrF₃, there will be 17.6 grams of Br.

 

I hope you understood.  Good luck to you.

 

Yohan C.   (LV  NV)