Question

How many liters of oxygen (at stp) are required to form 10.5 g of h2o?

Answer 1

To calculate the number of liters of oxygen required to form 10.5 g of H2O at STP, we need to convert grams to moles of water and then use a mole ratio to find the moles of oxygen. Finally, we can use the ideal gas law to calculate the volume of oxygen, which is 6.97 L.

Step-by-step explanation:

To calculate the number of liters of oxygen required to form 10.5 g of H2O at STP (Standard Temperature and Pressure), we need to use the molar mass of water and convert grams to moles.

From the balanced chemical equation, we can see that 2 moles of H2O is formed for every 1 mole of O2.

Therefore, we can set up a ratio:

2 mol H2O : 1 mol O2

Now, let's calculate the moles of H2O:

Moles of H2O = mass of H2O / molar mass of H2O

Moles of H2O = 10.5 g / 18.015 g/mol

Next, we can use the mole ratio to find the moles of O2:

Moles of O2 = (moles of H2O) / 2

Finally, we can use the ideal gas law to calculate the volume of O2:

Volume of O2 = (moles of O2) x (22.4 L/mol)

Plugging in the values, we get:

Volume of O2 = (10.5 g / 18.015 g/mol) / 2 x 22.4 L/mol

Volume of O2 = 6.97 L

Answer 2

In a liter of gas AT STP, there's 22.414 moles. That is something to remember.

You want to make 10.5g of water, but we don't know how much that is until we know how many moles that is of water.

The molecular weight of water is about 18.02g/mol

so for every mole, or 6.022*10^23 molecules of water, that's 18.02 grams.

Ok, but you want 10.5 grams of water, so it's a proportion.

18.02g/1mol = 10.5g/?mol

solve for unknown to get moles and you get

(1/18.02)*10.5 = 0.5826859046... don't round yet to 3 significant figures.

That's how many moles of water you want.

Now for every mole of water, there's 2 moles of hydrogen and one mole of oxygen. But the ratio of oxygen to water is 1:1.

In other words, you need x amount of oxygen to make x amount of water, the same.

So knowing that you need 0.5826859046 moles of oxygen you need and that there's 22.414 moles of a gas in 1 L at STP, you can find how many liters this is.

22.414mol / 1L = 0.5826859046mol / XL

this number is big because it should still be in your calculator, we don't round until the end.

= 0.0259965...
NOW round to 3 significant figures originally from 10.5g in the problem and get

0.0260 L of oxygen needed