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3 years ago

EXTREME HURRY!! State the ionization constant expression Ka for lactic acid. Given: pKa = 3.85 and Ka = 1.4*10^-4 mol dm^-3

1 answer:

5 0

Ka expression for any substance:
Ka = [H+] [A-] / [HA]

In this case,
Ka = [H+][C₃H₅O₃-]/[C₃H₆O₃]
1.4 x 10⁻⁴ = [H+] [C₃H₅O₃-] / [C₃H₆O₃]

pKa = -log(Ka)
pH = -log([H+])
The difference between pKa and pH is that pH is the negative logarithm of only the concentration of hydrogen ions, while pKa is the negative logarithm of the ratio of the product of the concentrations of hydrogen ions and concentration of base to the concentration of acid.

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All atoms of uranium have the same

Aleksandr [31]

When uranium comes in contact with oxygen in the air, it rusts, just like iron does, but uranium rust is black and not red. Like other heavy atoms such as iron, uranium atoms have more neutrons than they do protons. Not all uranium atoms have the same number of neutrons.

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3 years ago

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pyrite is a mineral composed of 46.5 mass % iron and 53.5 mass % sulfur. determine the empirical formula for calcocite.

padilas [110]

The empirical formula for pyrite is FeS2.

HOW TO CALCULATE EMPIRICAL FORMULA:

The empirical formula represents the simplest whole number ratio of constituents element of a compound. The empirical formula of pyrite can be calculated as follows:

46.5 mass % Fe = 46.5g of Fe

53.5 mass % S = 53.5g of S

Next, we divide each element's mass value by its molar mass

Fe = 46.5g ÷ 56g/mol = 0.83mol

S = 53.5g ÷ 32g/mol = 1.67mol

Next, we divide each mole value by the smallest (0.83mol)

Fe = 0.83mol ÷ 0.83 = 1

S = 1.67mol ÷ 0.83 = 2.014

Approximately, the ratio of Fe to S is 1:2. Therefore, the empirical formula of pyrite is FeS2.

Learn more at: brainly.com/question/14044066?referrer=searchResults

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2 years ago

What is litmus paper used for? To indicate if all the reactants have been used up to determine if a chemical reaction has occurr

rjkz [21]

The main use of litmus is to test whether a solution is acidic or basic. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F).

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3 years ago

A pycnometer is a precisely weighted vessel that is used for highly accurate density determinations. Suppose that a pycnometer h

dexar [7]

Answer:

5.758 is the density of the metal ingot in grams per cubic centimeter.

Explanation:

1) Mass of pycnometer = M = 27.60 g

Mass of pycnometer with water ,m= 45.65 g

Density of water at 20 °C = d = $998.2 kg/m^3$

1 kg = 1000 g

$1 m^3=10^6 cm^3$

$998.2 kg/m^3=\frac{998.2 \times 1000 g}{10^6 cm^3}=0.9982 g/cm^3$

Mass of water ,m'= m - M = 45.65 g - 27.60 g =18.05 g

Volume of pycnometer = Volume of water present in it = V

$Density=\frac{Mass}{Volume}$

$V=\frac{m'}{d}=\frac{18.05 g}{0.9982 g/cm^3}=18.08 cm^3$

2) Mass of metal , water and pycnometer = 56.83 g

Mass of metal,M' = 9.5 g

Mass of water when metal and water are together ,m''= 56.83 g - M'- M

56.83 g - 9.5 g - 27.60 g = 19.7 g

Volume of water when metal and water are together = v

$v=\frac{m''}{d}=\frac{19.7 g}{0.9982 g/cm^3}=19.73 cm^3$

Density of metal = d'

Volume of metal = v' = $\frac{M'}{d'}$

Difference in volume will give volume of metal ingot.

v' = v - V

$v'=19.73 cm^3-18.08 cm^3=$

$v'=1.65 cm^3$

Since volume cannot be in negative .

Density of the metal =d'

= $d'=\frac{M'}{v'}=\frac{9.5 g}{1.65 cm^3}=5.758 g/cm^3$

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3 years ago

How does solubility differ between small versus large carbohydrates? Explain.

EleoNora [17]

Answer with Explanation:

Small and large carbohydrates have diverse structural properties. Such property allow them to have different solubility.

Solubility is a chemical property of a substance that allows it to dissolve in a given solvent.

Carbohydrates are made up of "monosaccharides." These are simple sugars and are considered small carbohydrates. On the contrary, "polysaccharide" is an example of a large carbohydrate. Monosaccharides are soluble in water while many polysaccharides are not soluble in water.

The high solubility of monosaccharides is mainly due to the presence of hydroxide (OH) groups. These groups are always ready to bond with water (H₂O). Many polysaccharides are not soluble in water because of intermolecular interactions that prevents it from binding with water. Its dissolution process is different when compared to the smaller molecules.

So, this explains the answer.

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3 years ago