Which is used to convert between mass and moles of a substance?

Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce

sergeinik [125]

Answer:

The empirical formula is = $C_4H_8O$

The formula of Valproic acid = $C_8H_{16}O_2$

Explanation:

Mass of water obtained = 0.166 g

Molar mass of water = 18 g/mol

Moles of $H_2O$ = 0.166 g /18 g/mol = 0.00922 moles

2 moles of hydrogen atoms are present in 1 mole of water. So,

Moles of H = 2 x 0.00922 = 0.01844 moles

Molar mass of H atom = 1.008 g/mol

Mass of H in molecule = 0.01844 x 1.008 = 0.018588 g

Mass of carbon dioxide obtained = 0.403 g

Molar mass of carbon dioxide = 44.01 g/mol

Moles of $CO_2$ = 0.403 g /44.01 g/mol = 0.009157 moles

1 mole of carbon atoms are present in 1 mole of carbon dioxide. So,

Moles of C = 0.009157 moles

Molar mass of C atom = 12.0107 g/mol

Mass of C in molecule = 0.009157 x 12.0107 = 0.11 g

Given that the Valproic acid only contains hydrogen, oxygen and carbon. So,

Mass of O in the sample = Total mass - Mass of C - Mass of H

Mass of the sample = 0.165 g

Mass of O in sample = 0.165 - 0.11 - 0.018588 = 0.036412 g

Molar mass of O = 15.999 g/mol

Moles of O = 0.036412 / 15.999 = 0.002276 moles

Taking the simplest ratio for H, O and C as:

0.01844 : 0.002276 : 0.009157

= 8 : 1 : 4

The empirical formula is = $C_4H_8O$

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 4×12 + 8×1 + 16= 72 g/mol

Molar mass = 144 g/mol

So,

Molecular mass = n × Empirical mass

144 = n × 72

⇒ n = 2

The formula of Valproic acid = $C_8H_{16}O_2$

7 0

3 years ago

Why does an oil-and-vinegar salad dressing have two separate layers?

Olegator [25]

This is because no matter how hard you try to shake or combine the oil and vinegar together, they eventually separate. This happens because vinegar and oil are made of very different types of molecules that are attracted to their own kind.

4 0

3 years ago

If 2.00 g of mg reacts completely with 50.0 ml of hcl solution, what is the molarity of the hcl solution? mg(s) + 2hcl(aq) → mgc

Amanda [17]

The molarity of HCl is calculated as below

find the moles of mg used
moles = mass /molar mass

= 2.00g/24 g/mol=0.083 moles
write the reacting equation
Mg(s) +2HCl (aq)= MgCl2(aq) + H2(g)

by use of mole ratio between Mg to HCl which is 1 :2 the moles of HCl is therefore
= 0.083 x2 =0.166 moles

molarity of HCl = moles of HCl/ volume in dm^3

that is 0.166/50 x1000= 3.3 M of HCl

6 0

4 years ago

Read 2 more answers

What is the wavelength of an electromagnetic wave that has a frequency of

Alik [6]

Answer:

B

Explanation:

To calculate questions like this, you need to make use of the equation below:

ν = c / λ

ν is the frequency, c is the speed of light, and λ is the wavelength

ν = c / λ

2.45 • 10^9 Hz = (3•10^8 m/s)/(λ)

λ = 0.122 m = B

3 0

3 years ago

Looking across period 4 of the periodic table, potassium (atomic number 19) is followed by calcium (atomic number 20), which is

Gnesinka [82]

Potassium. Atomic radius gets larger as it goes to the left.

6 0

4 years ago