Question

IS this right?

Answer 1

Pyridoxine contains 11 hydrogen atoms, 8 carbon atoms, 3 oxygen atoms, and 1 nitrogen atom. What is the chemical formula for pyridoxine?

Answer 2

yeah that's right

Answer 3

the order is kind of dumb/arbitrary but I believe this would be PSBr3

Answer 4

Oh because Br has the r which makes it last ? :/

Answer 5

I just looked it up and apparently groups 13-15 get priority over other nonmetals

tbh I've never heard of this rule

Answer 6

Calcium chloride contains only calcium and chlorine. What is the formula for this compound?

Answer 7

CaCl?

Answer 8

... well, according to the directions they gave you yes

Answer 9

INcoreect :/ It says this would not be neutral?

Answer 10

oh I misread the directions >_>

the charges are
Ca2+ and Cl- so you'd need 2 chlorine atoms per 1 calcium atom

Answer 11

CaCl2

Answer 12

yeah

Answer 13

for some reason I read it as 1 calcium atom and 1 chlorine atom

Answer 14

Could you explain this to me ? :/

Answer 15

*** hepta not septa ***

Answer 16

but what about the H2O

Answer 17

MgSO4 --> magnesium sulfate (the sulfate ion is the entire SO42-) ion
7H2O ---> heptahydrate

Answer 18

hydrate means water, so H2O --> ____ hydrate

Answer 19

oh okay

Answer 20

Don't you add up the molar masses from the periodic table?

Answer 21

what did I do wrong

Answer 22

I got confused by the 7h20 what do I do with the 7 when calculating the molar mass

Answer 23

The 7 applies to the whole water molecule (not the magnesium sulfate, just water) so you’d multiply the molar mass of water by 7

Answer 24

so 126.112 for the water molecule

Answer 25

246.5

Answer 26

only three sig figs, instead of rounding 246.466 to 246.5 you'd round down to 246

Answer 27

Okay I got that part. How do I determine the percent composition of the hydrate

Answer 28

What is the percent mass of magnesium sulfate in MgSO4⋅7H2O?

Answer 29

(molar mass of just the MgSO4 / total molar mass of the whole compound) * 100

Answer 30

to save some time, (120.37/246.466)*100

Answer 31

*now that I look at the other problem they actually wanted 4 sig figs for the molar mass of magnesium sulfate heptahydrate whoops*

Answer 32

I did 4 sig figs lol

Answer 33

If 28.0 g of MgSO4⋅7H2O is thoroughly heated, what mass of anhydrous magnesium sulfate will remain?

Answer 34

whatever percent you got from before * 28

Answer 35

Okay so do I subtract 28 from 126.112

Answer 36

hm, not quite, we calculated what percent of the whole compound is the magnesium sulfate part

so you'd just multiply (120.37/246.466) * 28

Answer 37

13.67

Answer 38

yeah that's what i got too

Answer 39

so if a certain number of grams is being heated or whatever and I want to calculate the remaining I would just multiply it?

Answer 40

and would this be g/mol

Answer 41

sort of

like, we calculated that MgSO4 makes up like 48% or whatever of the entire compound MgSO4 * 7H2O

this proportion remains the same regardless of how much MgSO4 * 7H2O there is

so in our example problem, there is 28.0g of MgSO4 * H2SO4 so 48% times 28.0 gives the amount of MgSO4, as desired

Answer 42

this particular problem is asking for mass, so g, not g/mol

Answer 43

Enter the formula for the compound formed between potassium and sulfur.

Answer 44

K2S

Answer 45

yeah that should be it

Answer 46

How many covalent bonds does carbon form if each of its unpaired electrons participate in one bond?

Answer 47

COuld you explain how I would do this problem

Answer 48

carbon is group 4A ---> 4 unpaired electrons ---> "each unpaired electron gets 1 bond" --> 4 bonds

Answer 49

so for oxygen it would be 6?

Answer 50

oh wait it would be 2?

Answer 51

hm, oxygen is a special case, it only gets 2

Answer 52

nitrogen= 5

Answer 53

is it basically imagining the lewis dot structure and imagining how many unpaired cases there would be

Answer 54

so nitrogen is 1?

Answer 55

oh, now I remember

since oxygen has 6 VElectrons it takes 2 extra for bonding, thereby making 2 bonds
since nitrogen has 5 valence electrons it takes 3 for bonding, thereby making 3 bonds

Answer 56

would this relate to electron configuration

Answer 57

i'm sorry im just trying to make connections because I just don't get it :/

Answer 58

oh by bonding you mean to make it a full shell which is 8?

Answer 59

yeah

Answer 60

so hydrogen would be 7

Answer 61

hydrogen is a special case, it doesn't follow the octet rule and only takes 1 bond

Answer 62

my explanations might not be the greatest, I just know from memory what they're supposed to be

Answer 63

No don't worry about it . i just like to go even deeper just so i am fully grasping the concept.

Answer 64

to be more specific hydrogen only has 1 electron normally, it doesn't fill up the second subshell which would have 8

Answer 65

hm, the three pairs in between are the bonding pairs and the two pairs on the outside are the lone pairs making C false

between A and B I feel like both could work but I'm leaning towards A because it's a triple bond not three separate covalent bonds

Answer 66

lemme double check

Answer 67

oh b?

Answer 68

yeah between a and b for me too :/

Answer 69

double checked with a friend and they say A as well

Answer 70

okay wasb wrong or was a just the best answer

Answer 71

"three single covalent bonds" technically this is a triple bond, which is counted as one bond not three

Answer 72

just need you to look this over if you could

Answer 73

1) metal + nonmetal or metal + metal --> ionic
nonmetal + nonmetal --> covalent

Answer 74

2) you're on the right track just write out the ratio

2:3

Answer 75

3) MnO4 gets a special name permanganate

so KMnO4 ---> potassium permanganate

Answer 76

covalent
ionic
covalent

Answer 77

for 1

Answer 78

yeah that's what i got too

Answer 79

and then #4

Answer 80

4a) I'm not 100% sure but diiodd is probably iodine not osmium

I2O7?

Answer 81

other ones look fine

Answer 82

compound nitrogen monoxide?

Answer 83

NO

Answer 84

yup