Question

Calculate the formula mass of each compound given below. Keep at least one decimal place in atomic masses from the periodic table.

Answer 1

@zepp

Answer 2

?

Answer 3

H2O2

Answer 4

find formula mass

Answer 5

Peroxyde, yes

Answer 6

i think i know how to do this

Answer 7

Mass per mole?

Answer 8

Simply add up the mass of each atom that peroxyde is composed of

Answer 9

cuz i remember my professor did it in class

Answer 10

so for H2O2 would be : 2(1.00)+2(16.0) = 2+32 = 34 amu right ?

Answer 11

Yep! :)

Answer 12

hi @stephstar101 how r u :)

Answer 13

Hey there :) Just watchin' you learn! Mwahahahaaaa

Answer 14

@zepp what about H2SO4

Answer 15

lol evil laugh!!! :)))

Answer 16

Same thing

2(H)+(S)+4(O)

Answer 17

ohh S and O is separated ?

Answer 18

Yup! They are, since they're separate elements!

Answer 19

kk, this one should be 98 right?

Answer 20

@stephstar101 What do you think about the answer? I'm lazy to take out my calculator :<

Answer 21

really now? i know you have a virtual calculator hiding somewhere !!! :O

Answer 22

You're good :) It's 34.01468 amu if you want the fancy decimal stuff

Answer 23

Don't want to click on icon :P

Answer 24

Oh and 98 is correct! :D

Answer 25

what about "Keep at least one decimal place in atomic masses from the periodic table."

Answer 26

uh oh o_0

Answer 27

thanks for the freebies medal!! :D

Answer 28

@zepp get your lazy self together before i smack u D:

Answer 29

I like watching people learn c: If they have the motivation to learn, they should be rewarded! :D

Answer 30

your just like chatting/spamming with us...naw im just kidding lol :D

Answer 31

I see that @stephstar101 loves chem :D

Answer 32

zepp hated chem :<

Answer 33

he loves physics! BOOO !

Answer 34

:D Chem and bio are quite fun!

Answer 35

just to let you guys know, i have completed 9/34 questions for a total of 4 hours! what the heck lol

Answer 36

I like Chem :(

Answer 37

Convert 1.65 × 10^24 atoms of carbon to moles of carbon.

Answer 38

uh oh here come the moles, i hate moles :<

Answer 39

ohh dont u gotta use Avogadro's number for this?

Answer 40

Aww, they aren't too bad! I actually have to go soon since it's nearing midnight, but yes Avogadro all the way

Answer 41

http://images.wikia.com/theregularshow/images/6/6d/Mole.jpg
You can't hate moles, moles are cute!

Answer 42

aww wtf ! with the extra long nails lmao

Answer 43

that is one ugly a$$ mole haha :))

Answer 44

is this right? 2.74x10^46

Answer 45

@zepp !!

Answer 46

?

Answer 47

That' wrong lol

Answer 48

welcome back blitz! lol

Answer 49

The number of Avogadro is used to find the number of atom in a mole
\[\text{Number of atoms in a mole}=\text{Number of mole} * 6.23*10^{23}\]
(I round the number)

Answer 50

6.23 ? i thought its 6.02 ?

Answer 51

Sorry, I left a 0 behind :s\[1.65 × 10^{24}=\text{Number of mole} * 6.023*10^{23}\]
That should be our formula

Answer 52

And the number of mole would be
\[1.65*10^{24}\div6.023*10^{23}\]

Answer 53

that's what i did =.=

Answer 54

(Division, not multiplication)

Answer 55

yes! i did division wth :| what did u get?

Answer 56

That http://puu.sh/JtvC

Answer 57

i didn't put parenthesis =.=

Answer 58

That must be the problem :P

Answer 59

How many moles of Fe2O3 are in 235 g of the compound?

Answer 60

ok let me try this first

Answer 61

Cool :)

Answer 62

idk if i did it right or not, but my final answer is 1.47

Answer 63

Alright so in Fe2O3, there's two Fe and 3 O
2(Fe)= 55.845*2 = 111.69
3(O)= 16*3 = 48

Fe2O3 = 111.69 + 48 = 159.69

Take the 235 and divide
235/159.69 = 2.1

Answer 64

1.47, sorry, not 2.1

Answer 65

So yep, that's right :)

Answer 66

:) thanks for the explanation !

Answer 67

yw :)

Answer 68

not you, i was thanking Blitz ! lol

Answer 69

psh

Answer 70

You are welcome :D

Answer 71

Blitz is a really helpful guy, he knows everything well, explain clearly, give good examples..everything you can ask of a tutors :0

Answer 72

blitz is awesome :)

Answer 73

So I don't explain well? :(

Answer 74

zepp you just lazyyy !! 50% of blitz muahahha :))

Answer 75

meh

Answer 76

@zepp I thought you need to be helpful here and not just talking rubbish... :/

Answer 77

yup ! he need to be more helpful and not disconnecting too much! and also get a new ISP lol

Answer 78

Next question? :D

Answer 79

lol :) your so hyper

Answer 80

How many moles of N are in 0.235 g of N2O?

Answer 81

i got this, just need you to chek my answer ok?

Answer 82

42 is the answer.

Answer 83

wow...i said hold on lmao ! -.-

Answer 84

wtf zepp ! screww u lol :D

Answer 85

:D

Answer 86

i got .0083 though ?

Answer 87

It's NO2 or N2O?

Answer 88

N2O !

Answer 89

Alright, first step would be see how many g does 1 mole of this weight
2(N) = 14
1(O) = 16

N2O = 14+16 = 30
30g/mol of N2O

We have 0.235 g
We'll simply divide, how many 30g/mol fits in there?
\(0.235g\div30g/mol=0.007833mol\)

You forgot a 7 somewhere

Answer 90

wait does the O even necessarily in this?

Answer 91

it only ask for "N"

Answer 92

omg I misread the question, hold on

Answer 93

.....

Answer 94

What @Blitzkrieg did was correct, there's 2 moles of N in 30g.

Answer 95

Since there's 0.007833mol of N2O that fits in 0.235 and there's 2 moles of N in 1 mole of N2O, you multiply that number by 2

Answer 96

2x14=28

Answer 97

and take .235/28 = .0084