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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

C55H72MgN4O5. How many atoms are in this molecule?

Bas_tet [7]

There are 137 atoms in this molecule. C55 + H72 = 127. 127 + Mg (one atom of magnesium = 128. 128 + N4 = 132. 132 + O5 = 137.

5 0

3 years ago

PLS ANSWER QUICKLY

vichka [17]

1. D
2. DR
3. SR
4. DR
5. C
6. SR
7. S
8. D
10. C

3 0

2 years ago

Explain why the nucleus of an atom is positively charged but the overall charge of an atom is neutral

gtnhenbr [62]

Answer:

The nucleus is positively charged because it contains all of the protons however the charge of an atom is neutral because there is an equal amount of protons (positive) and electrons (negative) meaning the opposite charges cancel each other out therefore making the atoms overall charge neutral.

Explanation:

8 0

2 years ago

Which is the most likely to be reduced?

NISA [10]

Answer : The correct option is, $Zn^{2+}$

Explanation :

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. That means, the loss of electrons takes place.

Or we can say that, oxidation reaction occurs when a reactant losses electrons in the reaction.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. That means, the gain of electrons takes place.

Or we can say that, reduction reaction occurs when a reactant gains electrons in the reaction.

According to the electrochemical series, $Zn^{2+}$ most likely to be reduced because

Hence, the ion most likely to be reduced is $Zn^{2+}$ .

3 0

2 years ago