Chemistry, 22.01.2020 00:31 sxbenn

Determine the molecular formula for each compound.
a) 94.1% oxygen and 5.9% hydrogen; molar mass = 34g
b) 50.7% carbon, 4.2% hydrogen, and 45.1% oxygen; molar mass = 142g

(would greatly appreciated if someone could explain the process, also use the correct amount of significant digits)

Answers: 1

Show answers

Answers

Answer from: Shabat

The molecular formula for compound (a) is H₂O₂

The molecular formula for compound (a) is C₆H₆O₄

Explanation:

A compound's molar mass determines what is the mass of one mole of that substance. One mole of a compound contains Avogadro's number of molecules = $6.022\times 10^\ 23$ molecules.

The percent composition of elements in 1 mole of compound can be used to get the exact number of moles of each element present in per mole of compound.

................................................................................................................................................

a) 94.1% Oxygen and 5.9% Hydrogen; molar mass = 34 g

The given compound's percent composition is as follows :

$Oxygen = 94.1\% \\Hydrogen = 5.9\%$

For O :

94.1% of oxygen refers to 94.1 g of Oxygen per 100 g of compound.

Mass of Oxygen in 34 g of compound = $34\times \frac{94.1}{100} = 31.994\ g$

To determine the number of moles of element O present in one mole of compound :

Molar mass of Oxygen = 15.9994 g/mol

The mass in grams of one mole of substance is called molar mass.

One mole of oxygen has 15.9994 grams of O.

Number of moles of O in 31.994 g of O = $\frac{31.994}{15.9994} = 1.9996$

In whole numbers,

Number of moles of O in 31.994 g of compound = 1.9996 ≈ 2

Similarly,

For H :

5.9% of hydrogen refers to 5.9 g of Hydrogen per 100 g of compound.

Mass of Hydrogen in 34 g of compound = $34\times \frac{5.9}{100} = 2.006\ g$

To determine the number of moles of element H present in one mole of compound :

Molar mass of Hydrogen = 1.00794 g/mol

The mass in grams of one mole of substance is called molar mass.

One mole of hydrogen has 1.00794 grams of H.

Number of moles of H in 2.006 g of H = $\frac{2.006}{1.00794} = 1.9901$

In whole numbers,

Number of moles of H in 2.006 g of compound = 1.9901 ≈ 2

The molecular formula for this compound (a) can be written as H_2O_2

...........................................................................................................................................

b) 50.7% Carbon, 4.2% Hydrogen, and 45.1% Oxygen; molar mass = 142 g

The given compound's percent composition is as follows :

$Carbon = 50.7\%\\Hydrogen = 4.2\%\\Oxygen = 45.1\%$

For C :

50.7% of carbon refers to 50.7 g of carbon per 100 g of compound.

Mass of Carbon in 142 g of compound = $142\times \frac{50.7}{100} = 71.994\ g$

To determine the number of moles of element C present in one mole of compound :

Molar mass of Carbon = 12.011 g/mol

The mass in grams of one mole of substance is called molar mass.

One mole of carbon has 12.011 grams of C.

Number of moles of C in 71.994 g of C = $\frac{71.994}{12.011} = 5.9940$

In whole numbers,

Number of moles of C in 71.994 g of compound = 5.9940 ≈ 6

For H :

4.2% of hydrogen refers to 4.2 g of Hydrogen per 100 g of compound.

Mass of Hydrogen in 142 g of compound = $142\times \frac{4.2}{100} = 5.964\ g$

To determine the number of moles of element H present in one mole of compound :

Molar mass of Hydrogen = 1.00794 g/mol

The mass in grams of one mole of substance is called molar mass.

One mole of hydrogen has 1.00794 grams of H.

Number of moles of H in 5.964 g of H = $\frac{5.964}{1.00794} = 5.9170$

In whole numbers,

Number of moles of H in 2.006 g of compound = 5.9170 ≈ 6

For O :

45.1% of oxygen refers to 45.1 g of Oxygen per 100 g of compound.

Mass of Oxygen in 142 g of compound = $142\times \frac{45.1}{100} = 64.042\ g$

To determine the number of moles of element O present in one mole of compound :

Molar mass of Oxygen = 15.9994 g/mol

The mass in grams of one mole of substance is called molar mass.

One mole of oxygen has 15.9994 grams of O.

Number of moles of O in 64.042 g of O = $\frac{64.042}{15.9994} = 4.002$

In whole numbers,

Number of moles of O in 31.994 g of compound = 4.002 ≈ 4

The molecular formula for this compound (b) can be written as C_6H_6O_4

Answer from: Quest

Google it that might work

Answer from: Quest

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.