7. during a recrystallization, the dissolved compound is sometimes treated with activated carbon, why?

Answer:

CaCO3 + 2HCl ---> CaCl2 + H2O + CO2

Explanation:

The reaction between solid calcium carbonate and a mineral acid such as aqueous HCl is a neutralization reaction and occurs with the evolution of CO2 gas.

The balanced equation is given below

CaCO3 + 2HCl ---> CaCl2 + H20 + CO2

The product CaCl2 is water soluble which accounts for why the stain is removed, while CO2 gas escapes away from the reaction surface.

Answer:

CaCO3(s) + 2HCl(aq) -------> CaCl2(aq) + 2CO2(g) + H2O(l)

Explanation:

CaCO3(s) + 2HCl(aq) -------> CaCl2(aq) + 2CO2(g) + H2O(l)

When an acid reacts with a metal carbonate a salt, carbon dioxide and water are formed. Hard water usually contain Ca^2+ in the form of Ca(HCO3)2. Minor heating causes CaCO3(calcium carbonate) to deposit on surfaces through which the hard water passes.

Calcium carbonate reacts with acids to produce a calcium salt, water and carbon dioxide: Calcium carbonate + Hydrochloric acid → Calcium chloride + Water + Carbon dioxide. The carbonate radical breaks up into carbon dioxide and oxygen; the oxygen binds with the acid's hydrogen ions to make water; and a solution of calcium chloride remains.

n H2 = m H2 / Mr H2

n H2 = 2 / 2

n H2 = 1 mol

n O2 = m O2 / Mr O2

n O2 = 4 / 32

n O2 = 0.125 mol

O2 is a limiting reactant

n H2O = (coef. H2O / coef. O2) • n O2

n H2O = (2 / 1) • 0.125

n H2O = 0.25 mol

m H2O = n H2O • Mr H2O

m H2O = 0.25 • 18

m H2O = 4.5 gr

According to Hamilton's Rule (Br > C), altruism is supported when the cost (C) is less than the benefit (B) multiplied by the relatedness coefficient (r). Among the given options with B = 20 and r = 0.5, the value of cost that satisfies the condition for altruism is c. Cost = 20.

According to Hamilton's Rule (Br > C), altruistic behavior is favored when the benefit (B) multiplied by the relatedness coefficient (r) is greater than the cost (C). In this case, B = 20 and r = 0.5.

To determine the evidence for altruism, we need to compare the value of cost (C) to the value of B multiplied by r (Br). Let's evaluate each option:

a. Cost = 40:

Since 20 (B) multiplied by 0.5 (r) is equal to 10 (Br), which is less than 40 (C), altruism is not supported.

b. Cost = 30:

Again, 20 (B) multiplied by 0.5 (r) equals 10 (Br), which is less than 30 (C). Therefore, altruism is not supported.

c. Cost = 20:

With a cost of 20, 20 (B) multiplied by 0.5 (r) equals 10 (Br). Since 10 (Br) is equal to 20 (C), this satisfies the condition of Hamilton's Rule, suggesting evidence for altruism.

d. Cost = 15:

With a cost of 15, 20 (B) multiplied by 0.5 (r) equals 10 (Br), which is greater than 15 (C). Thus, altruism is not supported.

e. None of the above:

Since option c (Cost = 20) satisfies the condition of Hamilton's Rule (Br > C), indicating evidence for altruism, the correct answer is not "None of the above."

Therefore, based on Hamilton's Rule (Br > C), the value of cost that yields evidence for altruism in this scenario is c. Cost = 20.

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Answer:

U gotta check ur book for that or Google maybe..

To determine the number of moles of oxygen in methyl tert-butyl ether (MTBE), we need to consider the molecular formula and the molar ratios of the elements. The molecular formula of MTBE is CH3OC(CH3)3. From the formula, we can see that for each molecule of MTBE, there is one oxygen atom.

Given that there are 67 moles of hydrogen in the sample, we know that the mole ratio of hydrogen to oxygen is 3:1 according to the formula. So, for every 3 moles of hydrogen, there must be 1 mole of oxygen. Therefore, the number of moles of oxygen in the sample is 67 moles / 3 = 22.33 moles. Rounding to 2 significant digits, the number of moles of oxygen in the sample of methyl tert-butyl ether is 22.33 moles.

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Anaplerotic reactions "produce oxaloacetate and malate to maintain constant levels of citric acid cycle intermediates". This is the correct option.

It is metabolic pathways that replenish the intermediates of the citric acid cycle to ensure that it can continue functioning properly.

Oxaloacetate and malate are intermediates of the citric acid cycle that can be depleted during certain metabolic processes.

Anaplerotic reactions can replenish these intermediates by producing them from other metabolic precursors.

For example, pyruvate carboxylase can use pyruvate and CO2 to produce oxaloacetate, while malic enzymes can convert malate to pyruvate and produce NADPH.

By producing oxaloacetate and malate, anaplerotic reactions help to maintain the levels of citric acid cycle intermediates and ensure that the cycle can continue to produce energy through oxidative phosphorylation.

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The three spheres that interact in the process of melting sea ice due to increased greenhouse gases are the atmosphere, hydrosphere, and cryosphere.

The atmosphere contains the greenhouse gases that trap heat, causing the Earth's surface to warm. The hydrosphere is the sphere that contains the ocean, which absorbs a large amount of the heat caused by the greenhouse gases. The cryosphere is the sphere that contains the ice, which is melting as a result of the warming caused by the greenhouse gases in the atmosphere and the heat absorbed by the ocean in the hydrosphere.

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Answer: 0.135 M

Explanation:

Answer:

Letter B

Explanation:

The shape of the molecule affects its function as it determines it's properties  and interactions.

Molecular shapes or more precisely geometry of molecules is a three dimensional arrangement by which atoms and chemical  bonds are present in a molecule .Molecular shapes affects many properties of a molecule like it's color, reactivity  and action.

The molecular shapes are important as they  play a vital  role in determining macroscopic properties like melting and boiling points. It also helps in prediction of the way by which the molecule reacts with the other molecule.

It majorly affects physical and chemical properties of compounds .The shape of the molecule is mostly determined by the repulsion caused among valence electrons which is stated by valence shell electron pair repulsion theory.

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Answer:

Se gasta menos dinero cocinando la comida en una estufa de propano.

Explicación:

Nos cuesta menos dinero preparar una comida en una estufa de propano en comparación con la estufa de butano porque el propano produce más calor en comparación con el butano. El propano produce más calor que el butano y es más eficiente en la combustión, por eso se necesita menos cantidad de propano para alcanzar la temperatura para cocinar los alimentos en comparación con el butano, que necesita más cantidad de combustible para cocinar los alimentos debido a una combustión ineficiente.

Answer:

Water is neutral because there is an equal concentration of hydronium ions and hydroxide ions.

Explanation:

Water autoionizes into equal parts hydronium and hydroxide ions, resulting in a neutral pH. This is because during the autoionization reaction, two water molecules yield one hydronium and one hydroxide.

The pH of pure water has been best described as neutral pH with equal hydronium and hydroxide ions. Thus, option A is correct.

pH has been described as the measurement of hydrogen ions in a solution. The pH has been measured on a scale of 1-14. pH 7 has been the neutral pH.

The higher hydronium ion concentration tends to move the pH from 7 towards 1. The higher hydroxide ion concentration tends to move the pH above 7.

The neutral pH has been neither acidic nor basic with the equal constituents of hydronium and hydroxide ion in the solution.

Thus, the pH of pure water has been 7. It has neutral pH with equal hydronium and hydroxide ions. Thus, option A is correct.

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Answer:

A.) 1:1

Explanation:

You can determine the mole ratio between substances by comparing their coefficients in the balanced equation. Both Cl₂ and Br₂ have coefficients of 1. Therefore, they have a 1 to 1 (1:1) relationship.

If you were comparing the mole ratio of Cl₂ and NaBr, they would have a 1:2 relationship because Cl₂ has a coefficient of 1 and NaBr has a coefficient of 2.

A redox reaction involves oxidation one species and reduction of other species. Oxidation is the process of the lose of electron and it occurs at anode and reduction is the gain of electrons. Thus option d is false.

A redox reaction is a type of reaction in which both oxidation and reduction occurs each for different species. One reactant species oxidizes by losing electron into the other species and the species which gained the electron is reduced.

Oxidation is the process by which an element or group forms its higher oxidation state by losing electron. Reduction is the process by which an element forms its lower oxidation state through gaining electron.

In an electrolysis two electrodes undergo redox reaction where the electrode at which oxidation occurs is called anode and the electrode where reduction takes place is called cathode. Thus option c is incorrect.

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While shareholders do hold a significant level of authority in most corporations, their power and influence may be limited in certain contexts and subject to various legal and regulatory requirements.

Anyone who holds at least one share of a company's stock or unit in a mutual fund is referred to as a shareholder. The firm is primarily owned by its shareholders, who also have specific rights and obligations.

In general, shareholders are considered the owners of a corporation, and they do have a significant level of authority in the company. However, it's not accurate to say that shareholders are the ultimate authority in every corporation.

In practice, the level of authority that shareholders hold can vary depending on the laws and regulations in the jurisdiction where the company is incorporated, as well as the company's organizational structure and governance practices.

For example, in a publicly traded company with a dispersed ownership structure, individual shareholders may have very limited authority to influence the decisions made by the board of directors and executive management team. On the other hand, in a closely held company with a smaller group of shareholders, each shareholder may have more direct involvement in the company's decision-making processes.

Additionally, there may be legal and regulatory requirements that limit the power of shareholders in certain areas, such as the appointment of certain executive officers or the adoption of major strategic initiatives. In many cases, decisions in these areas may be made by the board of directors or executive management team, subject to oversight by the company's shareholders.

Overall, while shareholders do hold a significant level of authority in most corporations, their power and influence may be limited in certain contexts and subject to various legal and regulatory requirements.

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Beer-law Lambert's states that a dye's absorbance is inversely proportionate to its concentration in cases like crystal violet.

The Beer-Lambert Law (also known as the Beer-Lambert-Bouguer Law) states that the absorbance of a dye such as crystal violet is directly proportional to its concentration. This means that as the concentration of the dye increases, the amount of light that is absorbed by the dye also increases. This law is important for measuring the concentration of a solution by measuring its absorbance of light. As the absorbance is directly proportional to the concentration, knowing the absorbance allows for the concentration to be calculated. Beer Lambert law, also known as the Beer-Lambert law of absorption, states that there is a linear relationship between the concentration of an absorbing species and the absorptivity of the material. In other words, the greater the concentration of a substance, the greater its ability to absorb light. This law is often used to measure and analyze the concentration of a particular substance in a given sample, such as the concentration of a dye in a solution.

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Answer:

B. 6m/s southeast

Explanation:

velocity= distance / time

= 180/ 30

6m/s southeast

Chloroplasts is an important part in the process of photosynthesis in some organisms. The chloroplast absorbs the energy in sunlight and uses it to produce sugars.

The main function of chloroplast in plants is to convert light energy into chemical energy via the photosynthesis process.

Photosynthetic chlorophyll is found in chloroplasts, which catch sunlight and converts it into chemical energy, releasing oxygen from water. All green plants and algae have chloroplasts. Chloroplasts help plants in the formation of food.

Chloroplasts are found in the leaves of the plant's guard cells. Chloroplasts contain a lot of chlorophyll, which helps to trap sunlight.  The chloroplast is capable of reproducing without any help from the rest of the cell.

The primary job of chloroplast is to produce food through the photosynthesis process. Chloroplast has a component called chlorophyll, which traps sunlight and is used for food synthesis or sugar and other organic molecules in all green plants. They also form lipid components and amino acids that are required for chloroplast membranes.

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Answer:

His phraseology and his turns of invention are too empirically pseudoscientific for the simplicity of nature.

Answer:

D. compound

Explanation:

Answer:

compound

Explanation:

study island

Answer:

B and C which are the same

Explanation:

neutral ph which ranges about from 0 to 7 it is about where water is

The combination of properties for a polar molecules is presence of polar bonds and an asymmetrical shape.

Polar molecules are molecules whose ends are oppositely charged.

Polar molecules consists of a strongly electronegative atom bonded to a weakly electronegative atom or an electropositive atom.

Polar molecules contain polar bonds and are asymmetrical.

Therefore, the combination of properties for a polar molecules is presence of polar bonds and an asymmetrical shape.

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To find the amount represented by the given sample, we have to use the molecular mass of Fe2O3, which is 160g/mol approximately.

The answer is 0.9375 moles of Fe2O3.

The reaction is:
C + Fe2O3 → CO2 + Fe
Given:
Mass of C = 38.9 g
38.9 g C x (1 mol C / 12.011 g C) = 3.239 mol C
Since 1 mol C will produce 1 mol CO2 in the reaction, the number of moles of CO2 formed is 3.239 mol.

Mole is a unit of measurement used in chemistry to measure the amount of a substance, usually in terms of its mass. One mole of a substance is equal to its molecular weight in grams. The term originated from the Latin word ‘moles’, which means ‘mass’. Moles are commonly used to measure the amount of a substance in a given volume.

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The chemical name of KI is potassium Iodide, Fe2O3 is ferric oxide , (NH4)3PO4 is ammonium phosphate.



Chemical name is just the name we use in our daily life and IUPAC name follows rules for naming a compound .

The chemical name is Ferrous sulphate and the IUPAC name is 2-dimethyl hexane.

Rules for chemical naming are :

1) Write the name of both elements.

2) Change the ending of second element.

3) Place prefix in front of each element based the number of atoms present .

4)There shouldn't be two vowels in one row .

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In a neutralization reaction, water is always formed. This is because a neutralization reaction involves the reaction of an acid and a base to form a salt and water.

The acid donates a hydrogen ion (H+) and the base donates a hydroxide ion (OH-) to form water (H+ + OH- -> H2O) and the remaining ions combine to form a salt. The salt formed depends on the specific acid and base used in the reaction. Therefore, the correct answer is: water.

Water is a transparent, colorless, odorless, and tasteless liquid that is essential for most forms of life. It is a chemical compound with the formula H2O, meaning it is made up of two hydrogen atoms and one oxygen atom, held together by covalent bonds.

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The term that best describes highly methylated and condensed DNA is "heterochromatin."

In the nucleus of eukaryotic cells, DNA is organized into two main forms: euchromatin and heterochromatin. Heterochromatin is characterized by its dense and compact structure, which makes it inaccessible for transcription factors and other proteins involved in gene expression. Methylation of DNA occurs when a methyl group is added to the DNA molecule, usually at specific regions called CpG islands.

Methylation plays a crucial role in gene regulation and can lead to gene silencing by preventing the binding of transcription factors to the DNA. Therefore, highly methylated and condensed DNA is typically associated with reduced gene activity and limited access to the underlying genetic information.

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Answer:

65.2%

Explanation:

It is given that :

\($2NO + O_2 \rightarrow 2NO_2$\)

Therefore, 60 g of nitrogen oxide will produce 92 g of nitrogen dioxide

or 60 kg of nitrogen oxide will produce 92 kg of nitrogen dioxide

or 1500 kg of nitrogen oxide will produce \(2300\ kg\) of nitrogen dioxide

Therefore the percentage yield = (Actual yield / Expected yield) x 100

percentage yield = \($\frac{1500}{2300} \times 100$\)

Percentage yield = 65.217 %

Answer:

the person above me is correct, the answer for this is 65.2% or option D!

Explanation:

thank you person above me! i got a 100% on the test! :D

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The Balanced Chemical Equation for above reaction is :

\( \small \mathrm{Cu(OH)_2+ 2HCI\rightarrow CuCl _ 2 + 2H2O}\)

_____________________________

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1.78 grams of silver can be produced from 1.40 g silver nitrate and excess copper. The balanced chemical equation for the reaction of copper with silver nitrate (use cu2) is as follows: Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

To determine how many grams of silver can be produced from 1.40 g of silver nitrate and excess copper, we first need to calculate the limiting reactant.

The stoichiometry of the reaction is such that 2 moles of silver nitrate react with 1 mole of copper to produce 2 moles of silver. The molar mass of silver nitrate is 169.87 g/mol while that of copper is 63.55 g/mol,

therefore, the number of moles of silver nitrate present in 1.40 g can be calculated as follows:Number of moles of silver nitrate = mass/molar mass= 1.40/169.87= 0.008240 molSimilarly, the number of moles of copper required to react with this quantity of silver nitrate is 0.004120 mol (half of the number of moles of silver nitrate).

Since there is an excess of copper, it will not limit the reaction and hence the limiting reactant is silver nitrate.To calculate the mass of silver produced, we use the molar mass of silver, which is 107.87 g/mol.Mass of silver produced = number of moles of silver x molar mass= 0.01648 x 107.87= 1.78 g

Therefore, 1.78 grams of silver can be produced from 1.40 g silver nitrate and excess copper.

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