Complete the following table:

Complete the following table: (In this problem you are to determine the values for each of the empty entries. The goal of this problem is for you to become comfortable with the moles, molar mass, and Avogadro's number. If you would like some help use the Help table below. To check your answers use the Answer table.)

ANSWER Table:

Formula	M, Molar Mass (g mol^-1)	m, Mass of sample (g)	n, Moles of sample (mol)	N, Number of atoms, molecules or formula units
H₂SO₄	98.0	0.825

Answer:

In this case the compound is sulfuric acid, H₂SO₄, we are given the molar mass, 98 grams mol^-1 and a sample with a mass of 0.825 g. Even though the molar mass was given, it could be calculated by adding the atomic mass for two hydrogen atoms, one sulfue atom and four oxygen atoms. Check it if you are not sure. As long as we know the formula of the substance the molar mass can be determined by summing the atomic masses of the elements in the formula.

The first blank cell is the moles of the sample. To determine the number of moles in the sample the mass of the sample must be converted to moles using the molar mass. This can be set-up by the following conversion,

Note: the molar mass says there are 98.0 g of H₂SO₄in 1 mol of H₂SO₄. This says for H₂SO_4, 98.0 g H₂SO₄= 1 mol H₂SO₄. We can use this equality as a conversion to change grams to moles.

Formula	M, Molar Mass (g mol^-1)	m, Mass of sample (g)	n, Moles of sample (mol)	N, Number of atoms, molecules or formula units
H₂SO₄	98.0	0.825	8.42 x 10^-3

Now we can determine the number of molecules of H₂SO₄ in the sample. (Note: we had to calculate the number of moles in the sample before we could calculate the number of molecules.)

To convert moles to molecules Avogadro's number is used. Recall Avogadro's number relate the number in 1 mol. 1 mol of a substance contains 6.02 x 10²³particles. In this case H₂SO₄ is a covalent compound so the particles are molecules.

Formula	M, Molar Mass (g mol^-1)	m, Mass of sample (g)	n, Moles of sample (mol)	N, Number of atoms, molecules or formula units
H₂SO₄	98.0	0.825	8.42 x 10^-3	5.07 x 10²¹molecules

ANSWER Table:

Formula

M, Molar Mass (g ­ mol-1)

m, Mass of sample (g)

n, Moles of sample (mol)

N, Number of atoms, molecules or formula units

H2SO4

98.0

0.825

Answer:

The first blank cell is the moles of the sample. To determine the number of moles in the sample the mass of the sample must be converted to moles using the molar mass. This can be set-up by the following conversion,

Note: the molar mass says there are 98.0 g of H2SO4 in 1 mol of H2SO4. This says for H2SO4, 98.0 g H2SO4 = 1 mol H2SO4. We can use this equality as a conversion to change grams to moles.

Formula

M, Molar Mass (g ­ mol-1)

m, Mass of sample (g)

n, Moles of sample (mol)

N, Number of atoms, molecules or formula units

H2SO4

98.0

0.825

8.42 x 10-3

Now we can determine the number of molecules of H2SO4 in the sample. (Note: we had to calculate the number of moles in the sample before we could calculate the number of molecules.)

To convert moles to molecules Avogadro's number is used. Recall Avogadro's number relate the number in 1 mol. 1 mol of a substance contains 6.02 x 1023 particles. In this case H2SO4 is a covalent compound so the particles are molecules.

Formula

M, Molar Mass (g ­ mol-1)

m, Mass of sample (g)

n, Moles of sample (mol)

N, Number of atoms, molecules or formula units

H2SO4

98.0

0.825

8.42 x 10-3

5.07 x 1021 molecules

M, Molar
Mass (g mol^-1)

m, Mass of
sample (g)

n, Moles of
sample (mol)

N, Number of atoms,
molecules or formula units

H₂SO₄

Note: the molar mass says there are 98.0 g of H₂SO₄in 1 mol of H₂SO₄. This says for H₂SO_4, 98.0 g H₂SO₄= 1 mol H₂SO₄. We can use this equality as a conversion to change grams to moles.

M, Molar
Mass (g mol^-1)

m, Mass of
sample (g)

n, Moles of
sample (mol)

N, Number of atoms,
molecules or formula units

H₂SO₄

8.42 x 10^-3

Now we can determine the number of molecules of H₂SO₄ in the sample. (Note: we had to calculate the number of moles in the sample before we could calculate the number of molecules.)

To convert moles to molecules Avogadro's number is used. Recall Avogadro's number relate the number in 1 mol. 1 mol of a substance contains 6.02 x 10²³particles. In this case H₂SO₄ is a covalent compound so the particles are molecules.

M, Molar
Mass (g mol^-1)

m, Mass of
sample (g)

n, Moles of
sample (mol)

N, Number of atoms,
molecules or formula units

H₂SO₄

8.42 x 10^-3

5.07 x 10²¹molecules