____________  was the first chemist to organize elements by atomic number

1. Johann Wolfgang dobereiner

2. Antoine Lavoisier

3. Dimitri Mendeleev

4. Henry Moseley

5. John Newlands

Answer:

Region one because an area that has contour lines close together means that the area is steep. but in region ones case it has no contour lines meaning the area is flat.

Answer:

A. 1

Explanation:

The substance in the image above would be classified as a mixture of elements (option E).

A compound is a substance formed by chemical bonding of two or more elements in definite proportions by weight.

On the other hand, a mixture is made when two or more substances are combined, but they are not combined chemically.

According to this question, an image is shown with two different substances or elements as distinguished by coloration (white and purple). These elements are combined but not chemically bonded, hence, is a mixture.

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Answer:

hehe what is that??

The following statement that incorrectly describes mechanisms of CO2 transport is "7-10% of CO2 is dissolved directly into the plasma as bicarbonate ions in plasma."

The transport of carbon dioxide in the blood is done in three ways which are:

Dissolved CO2 Carbaminohaemoglobin Bicarbonate ions in the plasma

Dissolved CO2: This is the smallest fraction of carbon dioxide carried by the blood. Dissolved CO2 combines with water in the blood to form carbonic acid (H2CO3). This reaction is facilitated by an enzyme known as carbonic anhydrase. Carbonic acid dissociates to form H+ and bicarbonate ions (HCO3-).

Carbaminohaemoglobin: Just like oxygen, carbon dioxide can also bind with hemoglobin. Carbon dioxide binds with hemoglobin to form carbaminohaemoglobin. Carbaminohaemoglobin accounts for about 20% of the carbon dioxide transported by the blood.

Bicarbonate ions in the plasma: This is the largest fraction of carbon dioxide transported by the blood. Carbon dioxide diffuses from the tissues into the blood where it combines with water to form carbonic acid. Carbonic acid dissociates to form H+ and bicarbonate ions (HCO3-). The bicarbonate ions diffuse into the plasma where they are transported to the lungs. In the lungs, the bicarbonate ions diffuse back into the red blood cells. The bicarbonate ions are converted back to carbon dioxide, which is then exhaled.

The statement that incorrectly describes mechanisms of CO2 transport is "7-10% of CO2 is dissolved directly into the plasma as bicarbonate ions in plasma." This is incorrect because about 70% of CO2 is transported as bicarbonate ions, not 7-10%. Therefore, the statement is false.

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The mistake in the question's descriptions concerning CO2 transport involves the part of hemoglobin that carbaminohemoglobin binds to (it's the globin part, not the heme part), and the proportion of CO2 carried as bicarbonate ions in the plasma (it's about 70%, not 7-10%).

The mechanisms described here for the transport of CO2 in the body are partially incorrect. In the human body, around 20% of CO2 is indeed transported as carbaminohemoglobin, but it binds to the globin part, not the heme part, of the hemoglobin protein. Additionally, the primary way that CO2 is transported is as bicarbonate ions, but these bicarbonate ions constitute around 70%, not 7-10%, of the CO2 carried in the plasma. Therefore, the incorrect descriptions mentioned in the question are that carbaminohemoglobin binds to the heme part of hemoglobin and that only 7-10% of CO2 is carried as bicarbonate ions in the plasma.

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Water molecules have a stronger attraction than helium due to the presence of dipole-dipole interactions resulting from the polarity of the water molecule.

Water molecules have a stronger attraction than helium due to the difference in their intermolecular forces. Intermolecular forces are the attractive forces that exist between molecules and play a crucial role in determining the physical properties of substances.

Water molecules have a polar nature, meaning they have a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.

This polarity arises from the unequal sharing of electrons in the O-H bonds due to oxygen's higher electronegativity compared to hydrogen. The presence of polar bonds within the water molecule gives rise to a dipole-dipole interaction.

In contrast, helium is a noble gas and exists as individual atoms. Helium atoms are electrically neutral and do not possess a permanent dipole moment.

As a result, helium exhibits weak intermolecular forces known as London dispersion forces or Van der Waals forces. These forces arise due to temporary fluctuations in electron distribution, causing temporary dipoles that induce dipoles in neighboring atoms or molecules.

The dipole-dipole interaction in water is stronger than the London dispersion forces in helium. This is because dipole-dipole forces are more significant when there are permanent dipoles in the molecules.

The stronger attraction between water molecules leads to higher boiling and melting points compared to helium.

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Answer:

You count the carbons. The way it is written is confusing but If there are ten carbons then its decane. If it’s 11 then its undecane

9 would be nonane

Explanation:

H2O + CO2 = CO2 Plus H2O + CH4. As there are 4 moles of both oxygen and hydrogen here on side that reacts but three and two moles, respectively,  the preceding equation also isn't balanced.

Response and justification CO2 and H2O are the end results of the chemical process. Methane combustion is depicted in the chemical equation. A chemical equation's arrow, which points to a product side, indicates the reaction's direction (shows the products).

Products are the organisms that emerge from chemical processes. In a chemical reaction, reactants go through a highly energy transition stage before becoming products. This reaction results in the consumption of the reactants.

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The third quantum number (m_l) of a 3s² electron in phosphorus is 0.

The third quantum number, denoted as m_l, represents the magnetic quantum number and describes the orientation of an orbital within a subshell. It can have integer values ranging from -l to +l, where l is the azimuthal quantum number.

In the electron configuration of phosphorus, we see that the 3s subshell is being filled. The azimuthal quantum number (l) for the 3s subshell is 0. Since the electron is in the 3s² subshell, there are two electrons present in the 3s orbital.

For the two electrons in the 3s orbital, they will have opposite spins due to the Pauli exclusion principle. However, the magnetic quantum number (m_l) for both electrons in the 3s orbital will be the same, which is 0.

Therefore, the third quantum number (m_l) of a 3s² electron in phosphorus is 0. This means that both electrons in the 3s orbital have the same orientation within the subshell.

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Answer:

The mass

Explanation:

the mass grams of 3.75 × 10 21 atoms of Li is

40. 21 atom of Li

Watch as Le Chatelier's principle predicts a color change as the equilibrium of two species of cobalt with distinct colors is upset. The two distinct colors of Co (II) combine to

What does a chemical reaction's equilibrium mean?

When the observable parameters, such as color, temperature, pressure, concentration, etc. do not vary, the process is said to be in equilibrium. If "balancing" is the definition of the word "equilibrium," it follows that a chemical process reflects an equilibrium between the products and reactants involved in the reaction.

The equilibrium constant is what?

Equilibrium: Both mechanical / chemical processes can be brought to it. The rates of the forward and rearward reactions are identical in an equilibrium condition. • Equilibrium parameter: Kc is calculated as the product concentration divided by the reactant concentration, with each component raised to the molecular system. In response,

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The correct option are option C,E that is bonds between a sulfur atom and two hydrogen atoms were broken.  Zinc atom formed a bond with one sulfur atom.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

In the give reaction, bonds between a sulfur atom and two hydrogen atoms were broken. zinc atom formed a bond with one sulfur atom.

Therefore, the correct option are option C,E.

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Answer:

It determines the number of molecules

Answer:

it means there are 3 hydrogen atoms in the compound.

i'm not sure, so sorryyy!

Answer: To determine which of the given compounds will result in a solution with a pH greater than 7, we need to consider the behavior of the cation and anion in each compound in water.

Compounds that are made up of the conjugate base of a weak acid and a strong base, or a strong acid and the conjugate base of a weak base, will result in a basic solution. The conjugate base of a weak acid will hydrolyze in water, producing hydroxide ions (OH-) and resulting in an increase in pH. The conjugate base of a strong acid or a strong base will not hydrolyze, so it will not affect the pH of the solution.

With this in mind, we can identify the following compounds that will result in a solution with a pH greater than 7:

Therefore, the compounds that will result in a solution with a pH greater than 7 are MgF2, Na2CO3, and KC2H302.

Option A "store all solutions in brown bottles" is NOT required to ensure that stock solutions are free of contamination.

A stock solution is a high concentration solution that is created to be diluted for a variety of laboratory activities. For example, if an experimenter wants to prepare 1 L of 0.1 mol/L hydrochloric acid (HCl), they will prepare 83.33 mL of concentrated HCl (12 mol/L) and then add it to 916.67 mL of water to make up the final volume.Steps to ensure stock solutions are free of contamination:One should always use the following steps to ensure that stock solutions are free of contamination:Never return excess chemicals to stock bottles.Do not place dropping pipettes in stock solution bottles.Only replace tops on reagent bottles after use.Store solutions in a cool, dry place. Avoid sunlight. Store all solutions in brown bottles.Keep all solutions labelled to avoid mixing them up.Examine your glassware for cleanliness before using it.Pipette liquids with care.

Avoid spilling on the ground. Avoid placing pipette tips on the table.Never use pipette tips or glassware that have been used to mix or carry other substances.Never attempt to taste or smell any chemicals or solutions.Wear protective gloves and lab coats when dealing with dangerous substances.

Stock solutions should always be checked for contamination before they are used. If contamination is suspected, the solution should be discarded.

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Answer: D: plutonium-239

Explanation: Got it right on the quiz

The table below shows a list of radioisotopes and their half-lives.

A 2-columns table with 10 rows. Column 1 is labeled radioisotope. Column 2 is labeled half-life. Lithium-5, 3 × 10⁻²² seconds; polonium-211, 0.516 seconds; Barium-139, 82.7 minutes; uranium-240, 14.1 hours; Bismuth-210, 5.012 days; uranium 232, 68.9 years; carbon-14, 5730 years; plutonium-239, 24,065 years; beryllium-10, 1.6 × 10⁵ years; uranium-238, 4.5 times 10 to the 9 years.

The radioisotope that has the longest half-life is the best to use in powering planet and space exploration vehicles because they can travel farther. The radioisotope is the best to use is:

d) plutonium-239

Plutonium-239 has the longest half-life of all the radioisotopes listed, at 24,065 years. This means that it will take 24,065 years for half of the plutonium-239 in a sample to decay. This makes it a good choice for powering planet and space exploration vehicles because it will last for a long time.

The other radioisotopes listed have much shorter half-lives. Lithium-5 has a half-life of 3 × 10⁻²² seconds, polonium-211 has a half-life of 0.516 seconds, barium-139 has a half-life of 82.7 minutes, uranium-240 has a half-life of 14.1 hours, bismuth-210 has a half-life of 5.012 days, uranium-232 has a half-life of 68.9 years, carbon-14 has a half-life of 5,730 years, and beryllium-10 has a half-life of 1.6 × 10⁵ years.

So, the best radioisotope to use for powering planet and space exploration vehicles is plutonium-239. It has the longest half-life, which means that it will last for a long time and provide a steady source of power.

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Most of the herbal fatty acids have a fair wide variety of carbon atoms, because their biosynthesis involves acetyl-CoA, a coenzyme wearing a -carbon-atom institution.

As the quantity of carbons in a fatty acid chain increases, so does the melting point as illustrated in the determine below. thus, shorter chain fatty acids are more likely to be liquid, whilst longer chain fatty acids are more likely to be solid at room temperature (20-25ᐤC, 68-seventy sevenᐤF).

Fatty acids are categorised according to the presence and wide variety of double bonds of their carbon chain. Saturated fatty acids (SFA) comprise no double bonds, monounsaturated fatty acids (MUFA) comprise one, and polyunsaturated fatty acids (PUFA) comprise more than one double bond.

Fatty acids may be divided into four fashionable classes: saturated, monounsaturated, polyunsaturated, and trans fats. Saturated fatty acids and trans fat are related to an improved hazard of coronary heart ailment.

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AConduction

B. Radiation

C. Convection

nswer:

Explanation:

Answer:

Compounds contain more than one type of material. Yet both compounds and elements are considered pure substances. 

Pure compounds are created when elements combine permanently, forming one substance

Extra:

So, a mixture can be separated into its original components, while a pure compound cannot.

N-type silicon semiconductors contain  more valence electrons than silicon and P-type contain fewer valence electrons than silicon.

A semiconductor is a material that has conductivity somewhere between that of an insulator and that of a conductor.

Semiconductors are also characterized by their electrical conductivity and by their ability to be modified based on the addition of impurities known as doping.

N-type silicon semiconductors are formed by doping silicon with a small amount of impurities that contain more valence electrons than silicon.

The added electrons from these impurities form a negative charge that allows current to flow through the material.

P-type silicon semiconductors are formed by doping silicon with a small amount of impurities that contain fewer valence electrons than silicon.

The added "holes" created by these impurities allow current to flow through the material by accepting electrons from the n-type material.

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Among the given options, hydrogen bonds between regions of the polypeptide chain are the most critical for maintaining the native tertiary structure of a globular protein. They provide specific and directional interactions, contributing significantly to the stability of the folded protein.

The most critical factor for maintaining the native tertiary structure of a globular protein is the hydrogen bonds between regions of the polypeptide chain in the folded protein. Here's why:

1. Hydrogen bonds are formed between the electronegative atoms, typically oxygen or nitrogen, and hydrogen atoms in the protein. They contribute to the stabilization of the folded structure by providing specific and directional interactions between different regions of the polypeptide chain.

2. The hydrophobic effect, which involves the burying of non-polar residues in the protein interior, is important for stabilizing the protein's overall structure, but it does not directly contribute to maintaining the native tertiary structure.

3. Disulfide bonds between cysteine (Cys) residues can form covalent bonds and play a critical role in stabilizing the tertiary structure of some proteins, especially those found in extracellular environments. However, not all proteins have disulfide bonds, and the absence of disulfide bonds does not necessarily lead to loss of the native tertiary structure.

4. Salt bridges, also known as ionic bonds, occur between oppositely charged side chains and contribute to the stabilization of protein structure. While they can play a role in maintaining the structure, they are generally less critical compared to hydrogen bonds.

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Answer:

iv it does not make but if im wrong dont report please!

At constant temperatures, the simplest approach to reduce the volume of a gas is to raise its pressure. So, at 700 bar, or 700 times normal atmospheric pressure, hydrogen has a density of 42 kg/m3, compared to 0.090 kg/m3 at normal pressure and temperature.

Hydrogen decreases metal oxides in the reactivity series below. That is, hydrogen can only decrease the oxides of metals that are less reactive than hydrogen itself.

High-Temperature Water Splitting: Chemical processes that split water to make hydrogen are fueled by high temperatures generated by solar concentrators or nuclear reactors.

The oxidation number of hydrogen gas is 0, but the oxidation state of hydrogen atoms in water is +1. As a result, the hydrogen atom has been oxidized. It acts as a reducing agent.

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Answer:

They are known as physical changes

The dot and cross diagram is a way of representing a molecule along with its valence electrons and respective bonds. Valence electrons are drawn as a dot or a cross, each element will have a different connotation. Around the atoms, circles are drawn that indicate the bonds and how the electrons are shared.

Carbon has 4 valence electrons and oxygen has 6, the dot-and-cross diagram of CO2 will be:

Dissolving sugar in water results in an increase in the entropy.

Hence, Option (D) is correct answer.

Measurement of randomness of a system is called entropy. It is an extensive property. It is a state function. Unit of entropy is JK⁻¹ mol⁻¹.

Now lets check all options one by one

Option (A): Freezing water

Freezing water decreases the entropy because here second law of thermodynamics does not violate.

So it is incorrect option

Option (B): Cooling water

Cooling water does not increases entropy because entropy increases when solid melts to give liquid.

So it is incorrect option

Option (C): Condensing water vapour

In Condensing water vapour the temperature of liquid phase decreases and thus kinetic energy decreases. The randomness will decrease and hence entropy will also decrease.

So it is incorrect option.

Option (D): Dissolving sugar in solute

In dissolving sugar in solute the solid dissociates to ions and  the randomness will increase and hence entropy will also increase.

So it is correct option

Thus from the above conclusion we can say that Dissolving sugar in water results in an increase in the entropy.

Hence, Option (D) is correct answer.

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1. 12 L = 12 dm³

2. 3.18 g

Given

1. Reaction

K₂CO₃+2HNO₃⇒ 2KNO₃+H₂O+CO₂

69 g K₂CO₃

2. 0.03 mol/L Na₂CO₃

Required

1. volume of CO₂

2. mass Na₂CO₃

Solution

1. mol K₂CO₃(MW=138 g/mol) :

= 69 : 138

= 0.5

mol ratio of K₂CO₃ : CO₂ = 1 : 1, so mol CO₂ = 0.5

Assume at RTP(25 C, 1 atm) 1 mol gas = 24 L, so volume CO₂ :

= 0.5 x 24 L

= 12 L

2. M Na₂CO₃ = 0.03 M

Volume = 1 L

mol Na₂CO₃ :

= M x V

= 0.03 x 1

= 0.03 moles

Mass Na₂CO₃(MW=106 g/mol) :

= mol x MW

= 0.03 x 106

= 3.18 g

Answer:

welcome to 2021 dude

its been a long time since i answered this but here is my new account

Explanation: