Tbr question??

[Graffiti]

How much calcium metal combines with one gram of oxygen to form CaO?

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[Rabolisk]

...Is this serious?

 

[Graffiti]

...Is this serious?

sadly, yes. i wasnt sure if we had to write out a balanced equation and take 0.1g oxygen as the limiting reagent in order to figure out how much calcium needed to be added.

 

[Rabolisk]

Why don't you try it out and I'll see if your answer is correct?

 

[Graffiti]

Why don't you try it out and I'll see if your answer is correct?

nevermind, i figured it out lol

1g of O2 equals 0.03 moles.
0.03 moles O2 x 2 moles Ca / 1 O2 = 0.06 moles Ca
0.06 moles Ca x 40g/mol = 2.5 grams Ca

i was just confused with the way they solved it. they did it by finding moles of CaO then using that to find grams Ca. both ways get the same answer.

 

[BerkReviewTeach]

nevermind, i figured it out lol

1g of O2 equals 0.03 moles.
0.03 moles O2 x 2 moles Ca / 1 O2 = 0.06 moles Ca
0.06 moles Ca x 40g/mol = 2.5 grams Ca

i was just confused with the way they solved it. they did it by finding moles of CaO then using that to find grams Ca. both ways get the same answer.

An easier way is to say that gCa : gO = 40 : 16 = x : 1.

Solving gives 40/16 = x/1 so 2.5 = x.

 

[Thirteeen]

How much calcium metal combines with one gram of oxygen to form CaO?

2 Ca + O2 --> 2 CaO

Therefore, based on the above equation:

80g of Calcium = Xg of Calcium
32g of Oxygen 1g of Oxygen

X = 2.5g

Hence, 2.5g of Ca is needed.

 

[BestDoctorEver]

...Is this serious?

The MCAT really got into people...Sometimes we might think too hard even if we see 2+2. Don't be so hard on the OP because this can happen to anyone.

 

[Rabolisk]

Thought it might be someone trying to get help on a homework or something.