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3 years ago

How do you convert the measured mass of a substance to moles?

2 answers:

7 0

To convert between mass and number of moles, you can use the molar mass of the substance.

Hope I helped : )

Sonja [21]3 years ago

6 0

Use the molar mass of an element or compound to convert between the mass of a substance and the moles of a substance

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A student is given a 2.002 g sample of unknown acid and is told that it might be butanoic acid, a monoprotic acid (HC4H7O2, equa

Elina [12.6K]

Answer: The identity of the unknown acid is butanoic acid or ascorbic acid.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}$

Molarity of NaOH solution = 0.570 M

Volume of solution = 39.55 mL

Putting values in above equation, we get:

$0.570M=\frac{\text{Moles of NaOH}\times 1000}{39.55}\\\\\text{Moles of NaOH}=\frac{0.570\times 39.55}{1000}=0.0225mol$

The chemical equation for the reaction of NaOH and monoprotic acid follows:

$NaOH+HX\rightarrow NaX+H_2O$

By Stoichiometry of the reaction:

1 mole of NaOH reacts with 1 mole of HX

So, moles of monoprotic acid = 0.0225 moles

The chemical equation for the reaction of NaOH and diprotic acid follows:

$2NaOH+H_2X\rightarrow 2NaX+2H_2O$

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of diprotic acid

So, moles of diprotic acid = $\frac{0.0225}{2}=0.01125moles$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

For butanoic acid:

Mass of butanoic acid = 2.002 g

Molar mass of butanoic acid = 88 g/mol

Putting values in above equation, we get:

$\text{Moles of butanoic acid}=\frac{2.002g}{88g/mol}=0.02275mol$

For L-tartaric acid:

Mass of L-tartaric acid = 2.002 g

Molar mass of L-tartaric acid = 150 g/mol

Putting values in above equation, we get:

$\text{Moles of L-tartaric acid}=\frac{2.002g}{150g/mol}=0.0133mol$

For ascorbic acid:

Mass of ascorbic acid = 2.002 g

Molar mass of ascorbic acid = 176 g/mol

Putting values in above equation, we get:

$\text{Moles of ascorbic acid}=\frac{2.002g}{176g/mol}=0.01137mol$

As, the number of moles of butanoic acid and ascorbic acid is equal to the number of moles of acid getting neutralized.

Hence, the identity of the unknown acid is butanoic acid or ascorbic acid.

5 0

3 years ago

Which of the above electron dot diagrams is wrong and why?

Elodia [21]

Answer:

Oxygen, it's supposed to have six valenge electrons.

Explanation:

Count the dots on the oxygen atom, you'll see seven, but there's supposed to be six.

5 0

3 years ago

Read 2 more answers

(10 points) easy WILL GIVE BRAINLIEST

nignag [31]

Answer:

Both b/c a chemical formula tells you how many and a sketch formula shows how they are bonded together.

Molecular formulas show how many atoms of each element one molecule of a compound contains. Note: Ionic compounds are generally crystalline solids with high melting points. Other compounds, however, have very different properties.

4 0

2 years ago

Read 2 more answers

A 4.00g sample of helium has a volume of 24.4L at a temperature of 25.0oC and a pressure of 1.00 atm. The volume of the helium i

Masteriza [31]

Answer:

0.41 moles.

Explanation:

Given that:

Mass of helium = 4.00 g

Initial Volume = 24.4 L

initial Temperature = 25.0 °C =( 25 + 273) = 298 K

initial Pressure = 1.00 atm

The volume was reduced to :

i.e

final volume of the helium - 10.4 L

Change in ΔV = 24.4 - 10.4 = 10.0 L

Temperature and pressure remains constant.

The new quantity of gas can be calculated by using the ideal gas equation.

PV = nRT

n = $\frac{PV}{RT}$

n = $\frac{1.00*10.0}{0.082057*298}$

n = 0.4089 moles

n = 0.41 moles.

7 0

2 years ago

carbon dioxide at 25 degrees celsius and 101.3 kpa has a density of 1.799 kg/m^3 determine gas constant

dusya [7]

Answer:

Explanation:

Temperature of gas in absolute scale T = 25 + 273 = 298 .

pressure of gas P = 1.013 x 10⁵ N / m²

density D = 1.799 kg / m³

= 1799 g / m³

From gas formula

PV / T = n R Where P is pressure , V is volume and T is absolute temperature , n is no of moles

P / T = n R / V

P / T = m R /M V where m is mass of gas and M is molecular weight .

m / V = D ( density )

P / T = DR/ M

PM / DT = R

Putting the values

1.013 x 10⁵ x 44 / (1799 x 298)

R = 8.314.09 J / K mole

5 0

3 years ago