easy chemistry question?

[macman2790]

im having trouble with this one, im trying to figure out if the answer is eleven or 4.

How many oxygen atoms are represented by MgSO4•7H2O?

thanks

 

[killr_b]

im having trouble with this one, im trying to figure out if the answer is eleven or 4.

How many oxygen atoms are represented by MgSO4•7H2O?

thanks

I see five, unless you are combining and lose one.

 

[furcalchick]

11

seven water molecules, one oxygen in each of them, plus four from the other substance.

 

[lancestraz]

seven water molecules, one oxygen in each of them, plus four from the other substance.

Yup, it's eleven.

 

[macman2790]

Yup, it's eleven.

thanks, sorry but i actually have one more, im not sure how to figure out this one, but i think its 5.2

How many moles of CH3NH2 are in 6.0 g

thanks again

 

[furcalchick]

thanks, sorry but i actually have one more, im not sure how to figure out this one, but i think its 5.2

How many moles of CH3NH2 are in 6.0 g

thanks again

yeah, it's 5.2.

 

[mikes63737]

Unless I misread the problem, CH3NH2 is 31g/mole. 6 grams is 0.2 moles, not 5.2. You just divided the wrong way.

 

[Hummer]

Unless I misread the problem, CH3NH2 is 31g/mole. 6 grams is 0.2 moles, not 5.2. You just divided the wrong way.

Sounds like an answer I got on my Regents today.

 

[furcalchick]

Unless I misread the problem, CH3NH2 is 31g/mole. 6 grams is 0.2 moles, not 5.2. You just divided the wrong way.

oops.

 

[Jasonbot]

number of moles=mass/molar mass
x=6/31
x=0.193 moles