Molar mass is used in a conversion factor to calculate and uses the units of (not an multiple choice)

37.5 L

Explanation:

Data Given

volume of H₂S = 25.0 L

volume of O₂ = ?

Solution:

Reaction of Oxygen and H₂S is as below

                      2H₂S    +    3O₂   > 2SO₂ + 2H₂O

                      2 mole       3 mole

we come to know that 2 mole of H₂S  combine with 3 mole of O₂ and produce SO₂ and water

So,

Now we will calculate that how many liters of O₂ is Required to react with H₂S

So for this first we find moles of 25.0 L H₂S

  no. of moles = Volume in dm³ / molar volume at STP (22.4 dm³/mol)

So, we know

1 dm³ = 1 L

Put values in the above formula:

             no. of moles = 25 L / 22.4 L /mol

             no. of moles = 1.11 mol

So now apply Unity formula

if 2 mole of H₂S react with 3 mole of O₂ then how many mole will react with 1.11 mol of H₂S

                     2 mole of H₂S ≅ 3 mole of O₂

                     1.11 mole of H₂S ≅ ? mole of O₂

by doing cross multiplication

mole of O₂ = 3 mole x 1.11 mole / 2 mole

mole of O₂ = 1.67 mol

Now,

Convert mole to volume by using below formula

         no. of moles = Volume in dm³ / 22.4 dm³/mol

Rearrange the above equation

         Volume in dm³ =  no. of moles x 22.4 dm³/mol

Put values in above equation

        Volume in dm³ = 1.67 mol x 22.4 dm³/mol

        Volume in dm³ =  37.5 dm³ or L

So 37.5 L of volume is required to react with 25 L of H₂S

The roman numeral in copper(I) oxide indicates that the oxidation number of copper in the compound is 1.

Explanation:

Roman numeral is used to indicate the oxidation number of an element in a compound.

The roman numeral in copper(I) oxide indicates that the oxidation number of copper in the compound is 1.

This can be seen from the following illustration:

copper(I) oxide => Cu₂O

Oxidation number of O = –2

Oxidation number of Cu₂O = 0

Oxidation number of Cu =?

Cu₂O = 0

2Cu + O = 0

2Cu – 2 = 0

Collect like terms

2Cu = 0 + 2

2Cu = 2

Divide both side by 2

Cu = 2/2

Cu = 1

Thus, we can see that the oxidation number of Cu in Cu₂O is 1. Hence the name of Cu₂O is copper(I) oxide indicating that the oxidation number of of copper (Cu) in the compound is 1.

For copper(II) oxide, we shall determine the oxidation number of Cu. This can be obtained as follow:

copper(II) oxide, CuO => CuO

Oxidation number of O = –2

Oxidation number of CuO = 0

Oxidation number of Cu =?

CuO = 0

Cu + O = 0

Cu – 2 = 0

Collect like terms

Cu = 0 + 2

Cu = 2

Thus, the oxidation number of Cu in CuO is 2. Hence the name of CuO is copper(II) oxide indicating that the oxidation number of of copper (Cu) in the compound is 2.

From the above illustrations,

We can see that the roman numeral in both copper(I) oxide, Cu₂O and copper(II) oxide, CuO are different because the oxidation number of Cu in both cases are different.