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#### markosheehan

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- Jun 6, 2016

- 136

Im trying to work out the number of moles and then multiply by 32.

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- #1

- Jun 6, 2016

- 136

Im trying to work out the number of moles and then multiply by 32.

$n(O) = \dfrac{V(O)}{V_m(O)}$

Im trying to work out the number of moles and then multiply by 32.

$m(O) = n(O)M(O)$.

$V_m$ is the molar gas volume.

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- Jun 6, 2016

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Im sorry I am still confused. I know the right answer is .104g

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- Mar 5, 2012

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The molar volume of a gas ($V_m$) at room temperature and standard pressure is $24$ liter.Im sorry I am still confused. I know the right answer is .104g

That is, $1$ mole is $24$ liter.

How many moles does that make in $78\text{ cm}^3$?

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- Jun 6, 2016

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I feel the answer is wrong. 78/24000 ×32 is what gives the answer at the back of the book. Should it not be multiplied by 16 though because in the balanced equation for the reaction it's a half mile of oxygen is formed.?

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- Mar 5, 2012

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Not sure what you mean. Was there a reaction involved?

I feel the answer is wrong. 78/24000 ×32 is what gives the answer at the back of the book. Should it not be multiplied by 16 though because in the balanced equation for the reaction it's a half mile of oxygen is formed.?

We have 78/24000 moles of oxygen molecules ($O_2$).

Each molecule consists of 2 oxygen atoms, and an oxygen atom has mass 16u.

Therefore we multiply the moles with $2\times 16=32$.

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- #7

- Jun 6, 2016

- 136

h202 goes to h20 +.5o2

so does this not mean you would multiply it by 16 instead of 32