Question

When finding the mass of an equation such as Pb(NO3)2-- where is the 2 applied to the equation?

Answer 1

I'm assuming you mean the molar mass.

Pb - 207.2g*

2 is applied to both elements in the bracket. you multiply it.

N*2= 2N= 2*14= 28g*
O3*2=O6=6*16=96g*

add the 3 of those values (the ones with the asterisks) together and you'll have your molar mass for lead nitrate which is Pb(NO3)2

Answer 2

I got the molar masses of each element from the periodic table btw

Answer 3

Thank you! If the question says to determine the formula mass, is molar mass what is implied?

Answer 4

molar mass and formula mass are the same in this case

Answer 5

okay, thank you for your help!

Answer 6

no problem. don't hesitate to tag me & good luck!

Answer 7

I want to run the whole question by you because I feel like my answer came out to be too large. Determine the formula mass of Pb(NO3)2 in g/mol and convert 0.250g Pb(N)3)2 to moles Pb(NO3)2.

I did the first part of the question as you said and got an answer of 331g/mol. Then for the second part I ended up with 1324 moles. I'm new to chemistry but to me that seems like a high number of moles?

I set it up as:

0.250g/1mol=331g/mol/Xmol
0.250gX=331g/mol
0.250gX/0.250gX 331g/mol/0.250gX
X=1324 moles

Answer 8

0.250g*1mol/331g

remember what you want over what you got. we want moles, we have grams. grams cancel out and we calculate. that is your answer.