Nguyên tử nguyên tố sắt có 26e a. Viết cấu hình e của sắt b. Sắt thuộc nguyên tố s,p,d,f

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

What assumptions do we make in order to use the Henderson-Hasselbalch equation? a. Both the weak acid and its conjugate base are

zepelin [54]

Answer:

The final and initial concentration of the acid and it's conjugate base are approximately equal, that is we use the weak acid approximation.

Explanation:

The Henderson-Hasselbalch is used to calculate the pH of a buffer solution. It depends on the weak acid approximation.

Since the weak acid ionizes only to a small extent, then we can say that [HA] ≈ [HA]i

Where [HA] = final concentration of the acid and [HA]i = initial concentration of the acid.

It also follows that [A^-] ≈ [A^-]i where [A^-] and[A^-]i refer to final and initial concentrations of the conjugate base hence the answer above.

7 0

3 years ago

Which element most likely has the same number of valence electrons as silicon(si)?

Blizzard [7]

Answer:

Carbon, germanium, tin and lead.

Explanation:

The silicon is belong to the carbon family. There are five elements in carbon family carbon, silicon, germanium, tin and lead. These five elements are present in same group i.e group fourteen. The elements present in same group have same number of valance electrons.

For example.

Carbon electronic configuration:

C₆ = [He] 2s² 2p²

Silicon electronic configuration:

Si₁₄ = [Ne] 3s² 3p²

Germanium electronic configuration:

Ge₃₂ = [Ar] 3d¹⁰ 4s² 4p²

Tin electronic configuration:

Sn₅₀ = [Kr] 4d¹⁰ 5s² 5p²

Lead electronic configuration:

Pb₈₂ = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²

we can see that in case of all elements there are four valance electrons, which are equal to the valance electrons of silicon.

7 0

3 years ago

Leslie wants to know which advertising medium works best to promote her electronics store. She surveys her customers over a week

Korolek [52]

No survey to base on

7 0

3 years ago

Read 2 more answers

Is copper II chloride mixed with water an element, compound, or mixture? If it's a mixture is it homogeneous or heterogeneous?

Fittoniya [83]

Answer:

1. mixture

2. Homogenous

Explanation:

Copper II chloride is a compound because it consists of elements that are chemically combined together. When a solute in this case, copper II chloride is mixed with water- a solvent, the result is a homogenous mixture.

Homogenous substances are formed when a solute and a solvent combine, resulting in a mixture with uniform properties. Mixtures can be separated using relevant separation techniques.

7 0

3 years ago