Question

If anyone understands or has this worksheet please help ?!!!!!!!

Answer 1

Answer:

Part 1

1. empirical formula is = N₂O₃

2. empirical formula is = NaClO₄

3. empirical formula is = BaCr₂O₇

Part2

no. of atoms of P₄ = 2.1 x 10²³

Part 3

A) no. of moles of S = 0.88 moles

B) no. of atoms of Mg = 1.08 x 10²⁴

C) no. of moles of Br₂ = 9.5 mole

Part 4

A) Molar mass of Na₂SO₄ = 142 g/mol

B) Molar mass of Al₂(SO₄)₃ = 342 g/mol

C) Molar mass of Al₂(SO₄)₃ = 176.5 g/mol

D) Molar mass of K₂CrO₄ = 194 g/mol

Part 5,

mass in grams of I₂ = 254 g

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Explanation:

Part 1:

Empirical Formula Calculation from %

1): Data Given

Percent mass of N = 63.6 %

Percent mass of O = 36.4 %

First convert percent to mass

let say we have 100 g of compound

So

mass of N = 63.6 /100 x 100 = 63.6 g

mass of O = 36.4 /100 x 100 = 36.4 g

Now convert masses to moles:

Molar mass of N = 14 g/mol

Molar mass of O = 16 g/mol

Formula used:

               no. moles = mass in gram / molar mass ....................(1)

Now find the no. of moles of nitrogen

Put values in formula 1

              no. moles = 36.4 g / 14 g/mol

              no. moles = 2.6 mol

Now find the no. of moles of Oxygen

Put values in formula 1

                 no. moles = 63.6 g / 16 g/mol

                 no. moles = 4 mol

Now calculate the mole ratio of both element

N = 2.6 /2.6 = 1

O = 4 /2.6 = 1.5

To convert the ratio to whole number multiply the ratio with a whole number.

N = 1 x 2 = 2

O = 1.5 x 2 =3

So,

the ratio of N to O 2 : 3 and this is the simplest form

So the empirical formula is = N₂O₃

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2): Data Given

Percent mass of Na = 18.8 %

Percent mass of Cl = 29 %

Percent mass of O = 52.3 %

First convert percent to mass

let say we have 100 g of compound

So

mass of Na = 18.8 /100 x 100 = 18.8 g

mass of Cl = 29 /100 x 100 = 29 g

mass of O = 52.3 /100 x 100 = 52.3 g

Now convert masses to moles:

Molar mass of Na = 23 g/mol

Molar mass of Cl = 35.5 g/mol

Molar mass of O = 16 g/mol

Formula used:

                 no. moles = mass in gram / molar mass ....................(1)

Now find the no. of moles of Na

Put values in formula 1

                  no. moles = 18.8 g / 23 g/mol

                  no. moles = 0.82 mol

Now find the no. of moles of Cl

Put values in formula 1

                  no. moles = 29 g / 35.5 g/mol

                  no. moles = 0.82 mol

Now find the no. of moles of Oxygen

Put values in formula 1

                   no. moles = 52.3 g / 16 g/mol

                    no. moles = 3.3 mol

Calculate the mole ratio of both element

Na = 0.82 / 0.82 = 1

Cl = 0.82 / 0.82 = 1

O = 3.3 / 0.82 = 4

So,

The ratio of Na, Cl and O is 1 : 1 : 4 and this is the simplest form.

So the empirical formula is = NaClO₄

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3): Data Given

Percent mass of Ba = 38.9 %

Percent mass of Cr = 29.4 %

Percent mass of O = 31.7 %

First convert percent to mass

let say we have 100 g of compound

So

mass of Ba = 38.9 /100 x 100 = 38.9 g

mass of Cr = 29.4 /100 x 100 = 29 g

mass of O = 31.7 /100 x 100 = 31.7 g

Now convert masses to moles:

Molar mass of Ba = 137 g/mol

Molar mass of Cr = 52 g/mol

Molar mass of O = 16 g/mol

Formula used:

               no. moles = mass in gram / molar mass ....................(1)

Now find the no. of moles of Ba

Put values in formula 1

                no. moles = 38.9 g / 137 g/mol

                no. moles = 0.28 mol

Now find the no. of moles of Cr

Put values in formula 1

              no. moles = 29.4 g / 52 g/mol

              no. moles = 0.56 mol

Now find the no. of moles of Oxygen

Put values in formula 1

              no. moles = 31.7 g / 16 g/mol

               no. moles = 2 mol

Calculate the mole ratio of both element

Ba = 0.28 / 0.28 = 1

Cr = 0.56 / 0.28 = 2

O = 2 / 0.28 = 7

So,

The ratio of Ba, Cr and O is 1 : 2 : 7 and this is the simplest form.

So the empirical formula is = BaCr₂O₇

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****Note: the rest of the answer is in attachment.