Sulfurous acid is a diprotic acid with the following acid-ionization constants: Ka1 = 1.4x10−2, Ka2 = 6.5x10−8 If you have a 1.0 L buffer containing 0.252 M NaHSO3 and 0.139 M Na2SO3, what is the pH of the solution after addition of 50.0 mL of 1.00 M NaOH? Enter your answer numerically to 4 decimal places.


Answer 1


pH = 7.1581


The equilibrium of NaHSO₃ with Na₂SO₃ is:

HSO₃⁻ ⇄ SO₃²⁻ + H⁺

Where K of equilibrium is the Ka2: 6.5x10⁻⁸

HSO₃⁺ reacts with NaOH, thus:

HSO₃⁻ + NaOH → SO₃²⁻ + H₂O + Na⁺

As the buffer is of 1.0L, initial moles of HSO₃⁻ and SO₃²⁻ are:

HSO₃⁻: 0.252 moles

SO₃²⁻: 0.139 moles

Based on the reaction of NaOH, moles added of NaOH are subtracting moles of HSO₃⁻ and producing SO₃²⁻. The moles added are:

0.0500L ₓ (1mol /L): 0.050 moles of NaOH.

Thus, final moles of both compounds are:

HSO₃⁻: 0.252 moles - 0.050 moles = 0.202 moles

SO₃²⁻: 0.139 moles + 0.050 moles = 0.189 moles

Using H-H equation for the HSO₃⁻ // SO₃²⁻ buffer:

pH = pka + log [SO₃²⁻] / [HSO₃⁻]

Where pKa is - log Ka = 7.187


pH = 7.187 + log [0.189] / [0.202]

pH = 7.1581

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A(n) _______________ can be formed by linking together several monosaccharides via glycosidic bonds.



A polysaccharide (n) can be formed by linking several monosaccharides through glycosidic linkages.


Polysaccharides are carbohydrates or complex carbohydrates, where monosaccharides join with glucosidic bonds to form a more complex structure that would be the polysaccharide.

An example of a polysaccharide is starch, or glycogen.

Starch is found in many foods such as potatoes or rice, and glycogen is a form of energy reserve of our organism housed in muscles and liver to fulfill locomotion, physical activity, and other activities that consist of glycolysis.

Polysaccharides are degraded in our body by different stages, and several enzymes unlike monosoccharides or disaccharides, since they have more unions and a more complex structure to disarm in our body and thus assimilate it.

Polysaccharides are also part of animal structures, such as insect shells or nutritional sources, among others.

Which of the following are properties of acids? Check all that apply. • A. Corrosive • B. Reacts with certain metals • C. Tastes bitter □ D. Turns litmus paper blue



a) Corrosive and b) Reacts with certain metals

Which of the following statements about compounds is true?A- Each Compound contains only one element.
A- Each Compound contains only one element.

B- Compound can be classified as either heterogenous or homogenous.

C- A Compound has a defined ratio by mass of the elements that it contains

D- Compounds Vary in chemical composition depending on the sample size.


The following statements about compounds is true that a compound has a defined ratio by mass of the elements that it contains. Option C is correct.

A compound is a substance that is made up of two or more elements that are chemically bonded together. The elements in a compound are always present in a fixed ratio by mass. This means that no matter how much of the compound you have, the ratio of the elements will always be the same.

For example, water is a compound that is made up of hydrogen and oxygen. The ratio of hydrogen to oxygen in water is always 2:1 by mass. This means that no matter how much water you have, there will always be twice as much hydrogen as oxygen.

A compound can be classified as either homogeneous or heterogeneous, but not both. Homogeneous compounds have a uniform composition throughout, while heterogeneous compounds have different compositions in different parts of the sample. Compounds do not vary in chemical composition depending on the sample size. The chemical composition of a compound is always the same, regardless of how much of the compound you have. Option C is correct.

To know more about the Compounds, here



A and D is the answer

Hope the answer is right

Answer the following questions about the last lesson below. What did we figure out about chain reactions? What did we figure out about fission? Fission produce more energy than a typical fuel sources, chain reaction



(Nothing)-But No answer

Complete combustion of 7.80 g of a hydrocarbon produced 25.1 g of CO2 and 8.55 g of H2O. What is the empirical formula for the hydrocarbon? Insert subscripts as necessary



The empirical formula is C3H5


Step 1: Data given

Mass of the compound = 7.80 grams

Mass of CO2 = 25.1 grams

Molar mass of CO2 = 44.01 g/mol

Mass of H2O = 8.55 grams

Molar mass of H2O = 18.02 g/mol

Molar mass C = 12.01 g/mol

Molar mass H = 1.01 g/mol

Molar mass O = 16.0 g/mol

Step 2: Calculate moles CO2

Moles CO2 = mass CO2 / molar mass CO2

Moles CO2 = 25.1 grams / 44.01 g/mol

Moles CO2 = 0.570 moles

Step 3: Calculate moles C

For 1 mol CO2 we have 1 mol C

For 0.570 moles CO2 we have 0.570 moles C

Step 4: Calculate mass C

Mass C = 0.570 moles * 12.01 g/mol

Mass C = 6.846 grams

Step 5: Calculate moles H2O

Moles H2O = 8.55 grams / 18.02 g/mol

Moles H2O = 0.474 moles

Step 6: Calculate moles H

For 1 mol H2O we have 2 moles H

For 0.474 moles H2O we have 2*0.474 = 0.948 moles H

Step 7: Calculate mass H

Mass H = 0.948 moles * 1.01 g/mol

Mass H = 0.957 grams

Step 8: Calculate mol ratio

We divide by the smallest amount of moles

C: 0.570 moles / 0.570 = 1

H: 0.948 moles / 0.570 = 1.66

This means for 1 mol C we have 1.66 moles H   OR for 3 moles C we have 5 moles H

The empirical formula is C3H5

Final answer:

To find the empirical formula of the hydrocarbon, divide the moles of CO2 and H2O by their molar masses. Use the smallest mole ratio to determine the empirical formula.


To find the empirical formula of the hydrocarbon, we need to determine the mole ratios between carbon and hydrogen in the compound. First, calculate the moles of CO2 produced by dividing the mass of CO2 by its molar mass. Next, calculate the moles of H2O produced by dividing the mass of H2O by its molar mass. Finally, divide the moles of each element by the smallest number of moles to obtain the mole ratio between carbon and hydrogen. The empirical formula is CnHm, where n and m represent the mole ratios of carbon and hydrogen, respectively.

Learn more about Empirical formula here:


15.2 grams of CO2 = ? molecules of CO2



2.11 molecules of CO₂


Given data:

Mass of CO₂ = 15.2 g

Molecules of CO₂ = ?


Number of moles of CO₂:

Number of moles = mass/molar mass

Number of moles = 15.2 g/ 44 g/mol

Number of moles = 0.35 mol

Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ molecules

0.35 mol × 6.022 × 10²³ molecules / 1 mol

2.11 molecules of CO₂