The solvent in the developing tank is only 1 1/2 cm high and the samples are spotted at about 3 cm. why is it important to keep the spots above the solvent? explain precisely.

Answer:

-0.1051

Explanation:

First, we need to find the degree of dissociation (α) of each of the groups using the Handerson-Halsebach equation:

pH = pKa + log (α/1-α)

log (α/1-α) =  pH - pKa

log (1-α/α) = pKa - pH

1-α/α =[tex]10^{pKa - pH}[/tex]

1-α = [tex]10^{pKa - pH}[/tex]*α

α = [tex]\frac{1}{10^{pKa-pH} +1}[/tex]

So, fo the α-carboxyl group:

α = [tex]\frac{1}{10^{-6.03} +1}[/tex]

α = 1.0000

And for the α-amino group

α = [tex]\frac{1}{10^{0.93} +1}[/tex]

α = 0.1051

In the ionization, the α-carboxyl group goes from neutral to a negative ion with charge -1, and the α-amino group goes from a positive ion with charge +1 to a neutral compound. So, the net charge is how many ions are presented multiplied by the charge.

For the first one, the value of α is the value of ions, but for the second, α represents the neutral, so the ions are 1-α:

-1*(1.000) + (+1)*(1-0.1051) = -0.1051

Answer: A mole of Cu atoms has the same number of atoms as a mole of He atoms.

Explanation: Mole is a bigger unit that counts [tex]6.022*10^2^3[/tex]  . For example, one mole of electrons equals to [tex]6.022*10^2^3[/tex] electrons.

One mole of atoms equals to [tex]6.022*10^2^3[/tex] . First choice is correct as we have a mole of Cu and He(equal moles of Cu and He) and so the number of atoms will also be equal.

Second and fourth choices are not correct as a mole neither equals to [tex]6.022*10^2^4[/tex] nor equals to 6.022*10^2^2[/tex] .

Third choice is also not correct as if we have equal moles of carbon and He then number of atoms will be same.

So, the only and only correct choice is the first one. A mole of Cu atoms has the same number of atoms as a mole of He atoms.

Answer:

B

Explanation:

The scenario best illustrates the principle that cells are the basic unit of structure and function of all living things. Muscle function in a kangaroo's leg depends on the muscle cells, showing this principle of the cell theory. option B.

The component of the cell theory that this scenario best illustrates is: B. Cells are the basic unit of structure and function of all living things. This is because the function of the muscles in a kangaroo’s legs is determined by the cells that compose the muscle tissue, demonstrating that cells are the fundamental unit for both the structure and function of muscles.

According to the cell theory, there are three main principles:

All living things are made of cells

Cells are the basic unit of structure and function of all living things

All cells come from other cells

In this case, the focus is on the second principle, emphasizing the role of cells as the basic building blocks of muscles and their essential role in muscle function. option B.

Explanation:

The given data is as follows.

       [tex]V_{NaOH}[/tex] = 26.25 ml,        [tex]M_{NaOH}[/tex] = 0.1850 m

       [tex]V_{H_{2}SO_{4}}[/tex] = 25.00 ml,   [tex]M_{NaOH}[/tex] = ?

It is known that normality is n times molarity where "n" signifies the number of hydrogen or hydroxide ions.

Therefore, normality of NaOH is calculated as follows.

           [tex]N_{NaOH} = n \times M_{NaOH}[/tex]

                                     = [tex]1 \times 0.1850[/tex]

                                     = 0.1850 N

Normality of [tex]H_{2}SO_{4}[/tex] is calculated as follows.

          [tex]N_{NaOH}V_{NaOH} = N_{H_{2}SO_{4}}V_{H_{2}SO_{4}}[/tex]

              [tex]0.1850 N \times 26.25 ml = N_{H_{2}SO_{4}} \times 25.00 ml[/tex]

                      [tex]N_{H_{2}SO_{4}}[/tex] = 0.194 N      

Hence, molarity of [tex]H_{2}SO_{4}[/tex] will be as follows.

                     [tex]N_{H_{2}SO_{4}} = n \times M_{H_{2}SO_{4}}[/tex]

                    [tex]M_{H_{2}SO_{4}} = \frac{N_{H_{2}SO_{4}}}{n}[/tex]

                                         = [tex]\frac{0.194 N}{2}[/tex]

                                         = 0.097 M

Thus, we can conclude that molarity of the acid solution is 0.097 M.

Answer:

The answer is D

Explanation:

The amount of heat needed to raise the temperature of one gram of a substance by 1° Celsius is known as the specific heat. It is measured in joules per gram per degree Celsius and is distinct from the nutritional calorie concept.

The amount of heat needed to raise one gram of a substance by 1° Celsius is called the specific heat of the substance. Specific heat is a property that describes how much energy is needed to increase the temperature of 1 gram of the substance by 1°C. The common unit for specific heat is joules per gram per degree Celsius (J/g°C). When discussing the energy needed to change the temperature of water, we often refer to the calorie, which is the amount of heat required to raise 1 gram of water by 1°C, whereas in nutrition, the term "calorie" usually refers to a kilocalorie (1000 calories) and is the heat needed to raise 1 kilogram of water by 1°C.

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2 N₂ (g) + O₂ (g) ⇌ 2 N₂O

When nitrogen and oxygen reacts nitrous oxide is formed.

Molar mass of N = 14.0067 g/mol and N₂ = 28.0134
molar mass of O = 15.9998 g/mol 
molar mass of N₂O =28.0134 + 15.9998 =  44.0132 g/mol 

Now we first find the percent composition of N in N2O. 

(14.0067(2)/44.0128)100 = 63.65% of N 
 use the percent to find the mass of N in 74.0g of N₂O 

63.65% = 0.6365

74.0g (.6365) = 47.10g of N 

Now convert the g to mol 
47.10g (1 mol/14.0067g) = 3.36 mol N

1.71 x 10²¹ molecules of ascorbic acid.

The Problem:

How many molecules of ascorbic acid (vitamin C or C₆H₈O₆) are in a 500 mg tablet?

The Process:  

Step-1

We prepare the molar mass of ascorbic acid or C₆H₈O₆.  

Relative atomic mass (in rounding to integers):  

In ascorbic acid, there are six carbon atoms, eight hydrogen atoms, and six oxygen atoms. Therefore the molar mass is given by  

[tex]\boxed{(12 \times 6) + (1 \times 8) + (16 \times 6) = 176 \ g/moles}[/tex]  

Step-2

We calculate the moles of 500 mg ascorbic acid. Let us convert it to 0.5 g.

[tex]\boxed{ \ moles = \frac{mass}{molar \ mass} \ } \rightarrow \boxed{ \ moles = \frac{0.5 \ g}{176 \ g/mol} \ }[/tex]

Therefore we get 2.84 x 10⁻³ moles.

Step-3

Remember this, one mole contains 6.02 x 10²³ molecules, which is called The Avogadro's number.  

Let us convert 2.84 x 10⁻³ moles to the number of molecules (N).  

[tex]\boxed{ \ moles = \frac{N}{6.02 \times 10^{23}} \ } \rightarrow \boxed{ \ N = moles \times 6.02 \times 10^{23} \ } [/tex]

[tex]\boxed{ \ N = 2.84 \times 10^{-3} \ moles \times 6.02 \times 10^{23} \ \frac{molecules}{mol} \ }[/tex]

Thus the amount of molecules in 500 mg C₆H₈O₆ are [tex]\boxed{ \ 1.71 \times 10^{21} \ molecules \ }[/tex].  

- - - - - - -  

Quick Steps  

[tex]\boxed{ \ \frac{6.02 \times 10^{23} \ molecules}{1 \ mol} \times \frac{1 \ mole}{176 \ gram} \times 0.5 \ grams \ } = \boxed{ \ 1.71 \times 10^{21} \ molecules \ }[/tex]

Answer : True

Explanation : When storing parts outside it is best to keep them under tarps or wrapped to stay in compliance is true, because when we store the parts outside the house there are high chances of the parts getting exposed to environmental moisture. Which will develop rust on the parts and make it useless later on. To avoid this situation it is safer to keep it covered under the tarps or wrap it with something which can protect it from moisture.

Answer:

the first one is a

the second one is d

Explanation:

Anion solutions are typically prepared using sodium salts rather than calcium salts due to their better solubility and formation of inert anions. Sodium salts readily dissociate into ions in water and do not form insoluble compounds with certain anions unlike calcium salts. This ensures a clear anion solution without precipitates.

Anion solutions are typically prepared using sodium salts rather than calcium salts due to differences in solubility and reactivity. Sodium salts readily dissociate into ions when dissolved in water, producing the required anions. For instance, when the ionic compound of sodium chloride (NaCl) is dissolved in water, it dissociates into sodium (Na+) and chloride ions (Cl-). This creates a 1:1 stoichiometry of cations and anions as given by the formula, NaCl.

On the other hand, calcium salts like Ca(NO3)2 can also dissociate into ions in water, producing Ca²+ cations and NO3¯ anions. However, calcium salts often tend to form insoluble compounds with certain anions. This leads to precipitates in the solution, which could affect the outcome of certain experiments or reactions. Therefore, sodium salts, which are generally more soluble, are preferred for preparing anion solutions.

Apart from solubility factor, another reasoning for choosing sodium salts over calcium is that the former leads to inert anions that can better preserve the acidity or alkalinity of the solution. For example, isolating the chloride anion from a sodium salt results in an inert anion that does not engage in further chemical reactions, thereby maintaining the solution's basicity.

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Answer:

B.

Explanation:

THERE IS NO EXPLANATION NEEDED BECAUSE REASONS LOL

Answer:

the correct answer is C

Answer:

The correct answer will be- they all are living and thus are made of cells.

Explanation:

The living things show a characteristic feature which is that all living organism whether unicellular or multi-cellular, whether prokaryote or eukaryote are made up of cells.

Since, in the given question, a bacterium represents a prokaryotic organism, an amoeba represents a eukaryote and the carrot represents a multicellular organism, therefore, they all are made of the structural and functional unit called cells.

Thus, they all are living and thus are made of cells is the correct answer.

Answer:

d. (NH4)2SO4

Explanation:

Chemical formula of ammonium sulfate is (NH₄)₂SO₄.

Chemical formula is a way of representing chemical proportions of atoms present in a particular compound or molecule.It makes use of chemical symbols along with their valencies to be written.

The valencies are written as subscripts to elements after criss-crossing them with the other component.Group of atoms or radicals is written in brackets .Chemical formula fully specifies structure of compound without usage of words.Chemical formula in simplest form is called as empirical formula.

In ammonium sulfate, ammonium ion is positive radical with valency of +1 and sulfate ion is negative ion with valency of -2 . These are interchanged amongst themselves which gives the formula as(NH₄)₂SO₄.

Learn more about chemical formula ,here:

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Answer:

In the mentioned experiment, three kinds of variables are used, that is, the independent variable, the dependent variable, and the controlled variable. Of these the independent variables are the one that does not get modify, however, can be modified by the scientist, while the dependent variables are the one that modifies when the independent variables modify, and the controlled variables are the ones that are maintained same throughout.  

In the given experiment, the length of the wire, the type of the wire utilized, and the thermal conductivity of the wire are the independent variables.  

You can't substitute HNO₃ for H₂SO₄ because they differ in properties such as acid strength, oxidation powers and ion concentration, which affects the reactions' results in parts 4 and 5.

The substitution of concentrated HNO₃ solution for 3M H₂SO₄ in parts 4 and 5 wouldn't give the same results because of their differing chemical properties, such as their acid strengths, oxidation powers and ion concentrations.

HNO₃, or nitric acid, has an oxidation number of +5 which makes it a stronger acid than H₂SO₄ or sulfuric acid, with a sulfur oxidation number of +4. These acids also differ in their ion concentrations, reflected in the values for their ionization constants, or K values. H₂SO₄ has a higher K value, which means it provides a higher concentration of hydronium ions (H3O+), making it a stronger acid than HNO₃.

A change from H₂SO₄ to HNO₃ can drastically affect the equilibrium concentrations in the solution as well as the ensuing reactions' results. For instance, stronger acids like H₂SO₄ determine the concentration of hydronium ions in the solution, suppressing the ionization of weaker acids. Essentially, exchanging sulfuric acid with nitric acid would alter the system's equilibrium, potentially affecting the results of the reactions in parts 4 and 5.

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When solid silver acetate is put into water, it dissociates into silver ions (Ag+) and acetate ions (C2H3O2-) as it is a strong electrolyte.

The compound silver acetate (AgC2H3O2) is considered to be a strong electrolyte. When solid silver acetate is put into water, it dissociates into silver ions (Ag+) and acetate ions (C2H3O2-). The dissociation reaction can be written as follows:

AgC2H3O2 (s) → Ag+ (aq) + C2H3O2- (aq)

This reaction shows that solid silver acetate separates into its respective ions when dissolved in water. Although silver compounds, such as silver chloride, are typically sparingly soluble in water, the portion that dissolves does so by fully dissociating into its ions, demonstrating its behavior as a strong electrolyte.

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