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tatuchka [14]
3 years ago
12

Muscle physiologists study the accumulation of lactic acid [CH3CH(OH)COOH] during exercise. Food chemists study its occurrence i

n sour milk, beer, wine, and fruit. Industrial microbiologists study its formation by various bacterial species from carbohydrates. A biochemist prepares a lactic acid-lactate buffer by mixing 225 mL of 0.85 M lactic acid (Ka = 1.38 × 10−4) with 435 mL of 0.68 M sodium lactate. What is the buffer pH?
Chemistry
1 answer:
Alexus [3.1K]3 years ago
3 0

Answer:

4.1

Explanation:

First, we will calculate the moles of each species.

  • Lactic acid: 0.225 L × 0.85 mol/L = 0.19 mol
  • Lactate: 0.435 L × 0.68 mol/L = 0.30 mol

The volume of the mixture is 0.225 L + 0.435 L = 0.660 L

The concentration of the species in the buffer are:

  • Lactic acid: 0.19 mol/0.660 L = 0.29 M
  • Lactate: 0.30 mol/0.660 L =0.45 M

We can find the pH of the buffer using the Henderson-Hasselbach equation.

pH = pKa + log [lactate] / [lactic acid]

pH = -log 1.38 × 10⁻⁴ + log 0.45 M / 0.29 M

pH = 4.1

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olga_2 [115]
D=m/v

so,

d=8.0g/4.0cm

d=2

3 0
3 years ago
Calculate the molarity of each of the following
Alenkasestr [34]

Answer:

a. 1.21M

b. 0.119M

c. 0.00496M

Explanation:

Molarity, M, is an unit of concentration defined as the ratio between moles of solute and liters of solution:

a. 4.35 mol LiCl / 3.60L = 1.21M

b. 29.43gC6H12O6 * (1mol / 180.16g) = 0.1634moles / 1.37L = 0.119M

<em>Molar mass C6H12O6: 180.16g/mol</em>

c. 34.5mg NaCl = 0.0345g * (1mol / 58.44g) = 5.9x10⁻⁴moles / 0.1191L = 0.00496M

8 0
3 years ago
Calcule la molaridad de una solución acuosa de ácido sulfúrico (H₂SO₄) que se preparó al mezclar, en un recipiente aforado, 4 mo
oee [108]

Considerando la definición de molaridad, la molaridad de una solución acuosa de ácido sulfúrico (H₂SO₄) es 0.5 \frac{moles}{litro}.

La molaridad es una medida de la concentración de un soluto en una disolución que se define como el número de moles de soluto que están disueltos en un determinado volumen.

La molaridad de una solución se calcula dividiendo los moles del soluto por el volumen de la solución:

Molaridad=\frac{numero de moles de soluto}{volumen}

La Molaridad se expresa en las unidades \frac{moles}{litro}.

En este caso, sabes que una solución acuosa se preparó al mezclar 4 moles del ácido con suficiente agua hasta completar 8 litros de solución. Entonces, sabes que:

  • número de moles de soluto= 4 moles
  • volumen= 8 litros

Reemplazando en la definición de molaridad:

Molaridad=\frac{4 moles}{8 litros}

Resolviendo:

Molaridad= 0.5 \frac{moles}{litro}

Finalmente, la molaridad de una solución acuosa de ácido sulfúrico (H₂SO₄) es 0.5 \frac{moles}{litro}.

<em>Aprende más</em>:

  • brainly.com/question/17647411?referrer=searchResults
  • brainly.com/question/21276846?referrer=searchResults

8 0
3 years ago
Calculate the mass of 4.60 x 10^25 atoms of neon?
enyata [817]
I think it’s B 5.54 x 10^2g
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3 years ago
The weights of all elements are always compared to oxygen.
marishachu [46]

Answer:

The weights of all elements are always compared to the Carbon-12.

Explanation:

The weights of all elements are always compared to the Carbon-12 because the mass of carbon is 12 which is the exactly the sum of protons and neutrons.  

Oxygen was also considered the standard for some time but later this stander was rejected because in natural O¹⁷ and O¹⁸ were also present and this create the two different atomic mass tables.

AMU:

Atomic mass unit is define as the 1/12 the mass of an atom of carbon-12.

C12 has six neutron and six protons in the nucleus.

This unit is used to express the masses of atoms. We know that masses of atoms are very small and we do not have any such type of balance that can measure very small quantity. So that is way we use this scale to measure small quantity. For example, according to this scale

relative atomic mass of hydrogen is 1.008 amu

relative atomic mass of oxygen is 15.999 amu

relative atomic mass of uranium is 238.0289 amu

relative atomic mass of chlorine is 35.453 amu

7 0
3 years ago
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