What type of particles are represented by the crosses(X)? Helpp please

An aqueous solution contains 0.33 m ammonia. one liter of this solution could be converted into a buffer by the addition of 0.16 mol of HBr.

A buffer is defined as the solution of weak base and salt of weak base and strong acid.

or it is also defined as the solution of weak acid and salt of weak acid and strong base.

In this given problem,

NH3 behave as a weak base. On the other hand, NH4OH behave as a salt of weak base and strong acid.

As we know that, NH3 react with strong acid to form NH4OH.

Chemical equation:

NH3 + HBr ------ NH4OH

or NH4OH + HBr ------- NH4Br + H2O

Thus, we concluded that an aqueous solution contains 0.33 m ammonia. one liter of this solution could be converted into a buffer by the addition of 0.16 mol of HBr.

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Answer:

Explanation:Statement number two and three are correct.Others are incorrect

Here we have been given statements relating to valence bond theory and lewis theory.

The 1st statement is incorrect.Because we use the valence electrons for bonding.

Valence bond theory is based on the partial overlapping.Therefore this statement is incorrect.

The second statement is correct.

Valence bond theory can make predictions about geometrical parameters like bond angle,bond length etc

Third statement is correct.

Lewis theory explains only electron dot structures.

Fourth statement is incorrect.

Valence bond theory explains bond formation due to overlapping between different molecules and the sharing of electrons.

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Answer:

2 significant sigures

Explanation:

Answer: 1 significant figure

Explanation:

What are significant figures?

Significant firgues refer to the numbers following a decimal point. When undergoing addition, subtraction, multiplication, or division, this is determined by the limiting term.

The limiting term is the number that has the least amount of numbers after the decimal point.

This makes 2.2 the limiting term. Whatever answer is reported after the numbers are multiplied together, it must be rounded to where there is only 1 number following the decimal point.

The maximization of product production is a typical differential equations problem.

Equations come in two varieties: identities & conditional equations. All possible values of a variables result in an identity. Only certain combinations of the variables' values make a conditional equation true. 

The science of chemistry is logical. The fundamental ideas are yours to grasp. Although you can examine these ideas in any sequence, it is usually best to start at the top & work your way downward because many ideas depend on your knowledge of units, conversions, and interactions between atoms and molecules.

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Answer:

AgNO3(aq) is the limiting reactant

Explanation:

Cu(s) = 2 moles

AgNO3(aq) = 250/169.87 that is the molar mass and we get 1.47 moles

1.47 < 2

Answer:

Traits of Collectivist Cultures

In collectivistic cultures, people are considered "good" if they are generous, helpful, dependable, and attentive to the needs of others. This contrasts with individualistic cultures, which often place a greater emphasis on characteristics such as assertiveness and independence

Explanation:

Answer:

D carbohydrates

Explanation:living things are made of four types of molecules, known as macromolecules: proteins, lipids (fats), carbohydrates (sugars) and nucleic acids (DNA and RNA). Each type of macromolecule is made of its own building blocks, which are connected like Legos to form different shapes.

Answer: T2=233K

Explanation:

The pressure and volume change. The combined gas law is always needed for that concept.

P1*V1/T1=P2*V2/T2

Temperature MUST ALWAYS be in Kelvin

T1=90+273=363K

1200*85/363=850*350/T2

T2=233K

Hope this helps! :)

Physical weathering is caused by the effects of temperature changes on rocks, causing them to break apart. The process is sometimes aided by water.

Abrasion Weather effects such as wind and water break rocks into small pieces. Exfoliated weathered rock expands and fractures when pressure is released from unloading. Frostwedge rock cracks when water freezes and expands. Chemical weathering involves the interaction of rocks with mineral solutions (chemicals), changing the composition of rocks.

Rocks are formed by weathering and erosion that break down existing rocks through physical and chemical processes. Examples of chemical weathering include rust caused by oxidation and acid rain caused by carbonic acid dissolving rocks. Other Chemical Weathering B. Dissolution. Rocks and minerals break down to form soil.

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Answer: A. passes from one medium to another

Explanation: Light will change directions slightly forming a straight line.

1) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 14 is tetrahedral.

The general electronic configuration of group 14 elements is ns²np² and it is shown in box diagram in the attached image. When one electron is excited, it goes in vacant p-orbital and the p and s-orbital is half filled. It is shown in attached image.

When the another atoms are filled in the half-fiiled orbital, it forms sp³ hybridisation and its shape is tetrahedral.

Therefore, the shape of central atom of group 14 is tetrahedral.

2) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 15 is pyramidal.

The general electronic configuration of group 15 element is  ns²np³ and its box diagram is already shown in the image. When atoms are filled, it goes in p-orbital and pair of electron acts as a lone pair. Due to this lone pair, lone pair-bond pair repulsion is occurred and the geometry of the central atom is pyramidal.

Therefore, the shape of central atom of group 15 is pyramidal.

3) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 16 is bent.

The general electronic configuration of group 16 is ns²np⁴ and its box diagram is shown in the attached image. There are two electron pairs which acts as a lone pair and another two orbitals are filled by another atom. When they are filled, it shows lone pair-lone pair, lone pair-bond pair and bond pair-bond pair repulsion. Therefore, they are come closer to each other and forms bent shape.

Therefore, the shape of the central atom of group 16 is bent shape.

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Answer:Lanthanum

Explanation:

Lithium stars with the letter L in the periodic table.

What is lithium?

The chemical element lithium has the symbol Li and the atomic number 3. It is a silvery-white alkali metal that is soft. It is the least dense metal and the least dense solid element under ordinary conditions. Because lithium, like all alkali metals, is very reactive and combustible, it must be stored in a vacuum, inert environment, or inert liquid such as pure kerosene or mineral oil. It has a metallic shine when cut, but damp air quickly corrodes it to a dull silvery grey, then black tarnish. It is never found naturally, but only in (typically ionic) compounds such as pegmatitic rocks, which were historically the primary source of lithium. It is found in ocean water due to its solubility as an ion.

Lithium stars with the letter L in the periodic table. Other such elements are Lead, Lanthanum, Lutetium, etc.

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Answer:

Helium is a chemical element with the symbol He and atomic number 2

Helium is an element with the formula He and the atomic number 2.

What is an element?

A chemical element is a type of atom with a particular number of protons in the nucleus, such as the specific compound made up entirely of that species. Chemical elements, unlike chemical compounds, cannot be broken down into simpler substances by any chemical reaction. The number of protons in the nucleus is an element's defining attribute, and it is symbolised by the symbol Z - all atoms with the same atomic number are atoms of the same element. Atoms are rearranged into new compounds linked together by chemical bonds when various elements undergo chemical reactions.

Helium is an element with the formula He and the atomic number 2.

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Based on the equation of the reaction;

The percentage mass of iron in the ore is determined from the net ionic equation of the reaction as follows:

5 Fe²⁺ + MnO₄⁻ + 8H+ ---> 5 Fe³⁺ + Mn²⁺ + 4 H₂O

The mole ratio of the reaction shows that 5 moles of the iron (ii) ion is oxidized by 1 mole of tetraoxomanganate (vii) ion, MnO₄⁻.

The moles of tetraoxomanganate (vii) ion, MnO₄⁻ that reacted with al the iron present in the ore is determined as follows:

Moles of substance = molarity * volume in liters

Moles of tetraoxomanganate (vii) ion, MnO₄⁻ = 0.0281 * 39.42/1000

Moles of tetraoxomanganate (vii) ion, MnO₄⁻ = 0.001108 moles

Moles of iron (ii) ion present in the sample = 0.001108 * 5

Moles of iron (ii) ion present in the sample = 0.00554 moles

Mass of iron (ii) ion present in the sample = 0.00554 * 56

Mass of iron (ii) ion present in the sample = 0.31 g

Percent mass of iron in the ore = 0.31/1.362 * 100%

Percent mass of iron in the ore = 22.8%

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To calculate it using the formulas and learn about drug.

What is drug?

Drugs are by definition chemicals that, when ingested into a living system, influence or modify physiology. Both natural and artificial materials are acceptable. They are low-mass chemical structures, both in terms of atomic and molecular mass.

What is chemist?

At the atomic and molecular levels, chemists look into the characteristics of matter. They gauge proportions and reaction rates to better comprehend new substances and their behavior or to develop novel compounds for use in a variety of real-world scenarios.

Ratio of the compounds A and B are given as

compound A: compound B= 6:5

Now, chemist own to make a drug of 814ml, so we have to distribute these 814 ml in the ratio of 6:5. To make chemically correct drug.

Amount of compound=6/(6+5*814)

=6/11*814=444 ml

∴ Amount of compound a is needed 44 ml.

Therefore, 44 millimeters of a compound are needed.

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When 14. 8 grams of hydrogen is reacted with 34. 8 grams of oxygen. then water formed is 39.1935 grams.

A process that leads to the chemical transformation of one set of chemical substances to another is called a chemical reaction .

2H2 + 02 → 2H20

Given, mass of hydrogen = 14.8 grams

and we know molar mass of hydrogen = 2.02 g/mole

given, mass of oxygen = 34.8 grams

we know molar mass of oxygen = 32 g/mole

As we know that : moles is equal to mass / Molar mass

then, moles of hydrogen = 14.8g/ 2.02 g/mole = 7.33 moles

and moles of oxygen = 34.8g / 32g/mole = 1.0875 moles

For 2 moles hydrogen consumed, 1 mole of oxygen is needed.

This implies that oxygen is the limiting reagent and will be consumed completely.

We see that for 2 moles of H2 consumed,  1 mole of O2 is needed to produce 2 moles of H2O.

For 1.0875 moles of oxygen consumed, moles of H2O produced will be 2.175

We know, mass of H2O = moles of H2O * Molar mass of H2O

Hence, mass of H2O = 2.175 moles * 18.02 g/moles

Therefore, mass of H2O =39.1935 grams

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To filter runoff and stop soil erosion, locals are more likely to grow trees on their property alongside canals and roads.

What is soil erosion and what is its impact on water pollution?

Soil erosion is mostly caused by absence of trees, because the soil cannot hold itself. So if you add trees, there will be less soil erosion.

In addition to lowering soil productivity, soil erosion can have a substantial negative influence on water quality. In surface water bodies, sediment from soil erosion is a significant water quality problem. Reduced water quality is largely caused by increased amounts of phosphorus (P) and nitrogen (N) in surface waters.

When sediments are moved by soil erosion and surface water runoff, N,P can travel from fields into lakes and streams. The role of P- and N-rich sediment in creating eutrophication is one of the many issues that are frequently linked to soil erosion and sediment.

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The molarity of a solution made by adding 50 ml of 2.00 m nitric acid with enough water to make 450.0 ml of solution is 0.22 M

What is Molarity?

It is defined as number of moles of solute per liter of solution

M = n / V

where

n = no of moles

M = molarity

V = volume

Molarity in mL

M = (n / V ) * 1000

Moles of Nitric acid = (50/1000 )* 2 = 0.1 moles

Volume of solution is 450 mL

Substituting,

Molarity = ( 0.1 / 450)* 1000 = 100/450 = 0.22 M

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The reaction catalyzed by pyruvate carboxylase is an example of an anaplerotic reaction.

Anaplerotic reactions are metabolic processes that replace depleted oxaloacetate in the citric acid cycle. These processes aim to maintain stable ATP concentrations to enable continued cellular respiration.

The anabolic reaction known as the anaplerotic reaction aids in producing the intermediate components of the metabolic pathways. The name of the intermediate reaction step in such a reaction is anaplerotic pathways. Anaplerotic reactions play a significant role in metabolism, which means they are crucial for biochemical processes like lipid production and citric acid pathways. In this article, we primarily concentrate on the anaplerotic reaction and anaplerotic routes for anaplerotic pathways. It focuses on the physiological function of anaplerosis.

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Answer:

Explanation:

Inglish:

Some of the CO2 is released back into the atmosphere through plant respiration (ie plants "exhaling"). Plant-eating animals digest sugar molecules from plants for energy. During their respiration, excretion and decomposition they release some CO2 into the atmosphere.

español:(spanish)

Parte del CO2 se libera de nuevo a la atmósfera a través de la respiración vegetal (es decir, plantas "exhalando"). Los animales que comen plantas digieren las moléculas de azúcar de las plantas para obtener energía. Durante su respiración, excreción y descomposición liberan algo de CO2 a la atmósfera

Link reaction is the cellular respiration in animals. They produce carbon dioxide which is released to the air. This carbon dioxide is utilized plants for photosynthesis.  

Link reaction is composed of the glycolysis and aerobic respiration by mitochondria. In glycolysis, pyruvate molecule is decarboxylated and forms acetate. This stage produces carbon dioxide.

The pyruvate then dehydrogenate and losses its hydrogen to NAD+. The NADH formed is used to produce ATP during the process called oxidative phosphorylation.

The carbon dioxide removed by the process is taken by the green plants during photosynthesis to combine with water producing glucose which is stored as their chemical energy.

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You write the code chunk rename(Company...Maker.if.known. = Maker). The function that will modify the name of your column is rename().

The rename() function is used to rename a file or directory, from old name to new name, without altering the file's content. This function accepts the file's name as an argument. Renaming fields or reformatting their names is what the Rename Function is intended to do. Rename can be used for bulk renaming based on a JavaScript expression, or to change specific fields (much like the Eval Function). The rename command changes the name of the file or directory specified by oldname to the one specified by newname. The path to an already-existing file or directory must be in the old name. The name of an existing file or directory cannot be used as the new name.

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The molar concentration of h3O+ = 7.59 × 10^-4 M

What is pH value?

It is a measure of how acidic or basic water is. It is determined by its pH. From 0 to 14, with 7 serving as neutral, the range is available. Acidity is indicated by pH values lower than 7, while baseness is indicated by pH values higher than 7. A critical indicator of water quality is the pH of the solution.

The molar concentration of [H3O+] in a cola with a pH of 3.120 can be calculated by:

[H3O+]=10−pH

[H3O+]=10−3.120

[H3O+]=7.59×10−4M

Ingestion of large amounts of phosphoric acid found in cola can upset the body's regulation of bone metabolism and reduce the absorption of calcium from the diet. For this reason, people who are at risk of developing osteoporosis are often advised not to drink much cola.

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62.5 mL is prepare .

What is molarity?

Molar concentration is a unit of measurement for the concentration of a chemical species, specifically a solute, in a solution, expressed as the amount of substance per unit volume of solution. The most often used unit for molarity in chemistry is the number of moles per litre, denoted by the unit symbol mol/L or mol/dm3 in SI units.

Molarity of the stock solution as 0.100 M

Volume of the dilute solution as 250 mL

Molarity of dilute solution as 0.0250 M

We are required to calculate the Volume of the stalk solution.

Taking the volume and molarity of the stock solution to be V₁ and M₁ respectively, and volume and molarity of the dilute solution to be V₂ and M₂ respectively.

We are going to use the dilution formula;

According to the dilution formula, M₁V₁ = M₂V₂

Rearranging the formula;

V₁ = M₂V₂ ÷ M₁

   = (0.025 M × 0.25 L) ÷ 0.100 M

   = 0.0625 L

But, 1 L = 1000 mL

V₁ = 62.5 mL

Therefore, the volume of the stock solution is 62.5 mL

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The maximum temperature of the water after mixing is 38.51°C

Heat values is derived from the equation:

  q = mcΔT

where

q = heat ( J)

m= mass ( kg)

c = specific heat capacity

ΔT = change in temperature

T2 = final temperature

T1 = initial temperature

  M of H2O × c × ( T1 - T2) = M of H2O × c × ( T2 - T1 )

29.2 g × ( 78.2° - T2 ) = 67.3 × ( T2 - 21.3° )

2283.44 - 29.2 ×T2 = 67.3 × T2 - 1433.49

3716.93 = 96.5 × T2

T2 = 38.51°C

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Note: here is the completed question

Suppose you mix 29.2 g of water at 78.2°C with 67.3 g of water at 21.3°C in an insulated cup. What is the maximum temperature of the water after mixing?

When water freezes at [tex]O^{o}[/tex] Celsius. it will release heat.

When the liquid water turns to solid ice we find that water freezes without getting any colder. That's because the latent heat of fusion is being lost from the liquid as it solidifies and the temperature of the water does not fall so quickly

Does freezing water release heat?

When water becomes a solid, it releases heat, warming up its surroundings. This makes freezing an exothermic reaction.

Does water melt or freeze at 0 Celsius?

At temperatures below 32°F (0°C), liquid water freezes.

Thus, when water freezes at [tex]O^{o}[/tex] Celsius. it will release heat.

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Based on the half-life of the material, the isotope is radium-226; option D

The half-life of a substance is the time taken for half of the amount of material present in the original sample of the material to decay.

The half-life of materials differs from each other. The half-life may be in millions of years for some materials, whereas for some materials, the half-life could only be in seconds.

The half-life of materials is constant.

Considering the given material;

One-eighth of the mass of the original sample of the radioisotope remains unchanged after 4,800 years.

For one-eight of the material of the isotope to remain, the number of half-lives it has undergone will be;

after one half-life = half of the original sample remains

after two half-lives = one-fourth of the original sample remains

after three half-lives = one-eight of the original sample remains

The half-life of the isotope = 4800/3

The half-life of the isotope = 1600 years

Radium-226 has a half-life of 1600 yers

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This structure is incorrect because the octet rule is not fulfilled.

Lewis formulated the "octet rule" in his atom theory. The octet rule generally refers to the tendency of atoms in order to have eight electrons in the valence shell. When the atoms have fewer than eight electrons, they tend to react with other atoms and form more stable compounds. Usually atoms will react to get in the most stable state possible that is will try to satisfy the octet rule.

To find if octet is satisfied first we need to  determine the number of electrons from lone pairs and bonds to the atom. Each lone pair will donate  two valence electrons to the atom and each bond is represented by a line, gives two valence electrons to the atom. Second we need to confirm that the added up number of valence electrons is 8, or 2 for hydrogen.

In case of CO2 we can see that the octet rule is not satisfied so its the wrong structure.

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The molecules of two liquids mix together and form a new liquid. However, the liquid formed might be miscible or immiscible.

When two liquids are mixed together it forms a new solution. The new liquid has the properties of both of the original liquids.

The formed liquid may either be miscible or immiscible depending upon the properties of the two liquids.

Miscible liquids become homogeneous solutions so that their composition would be uniform. This is done by the complete diffusion of both liquids.

But in the case of immiscible liquids, the solution forms two separate layers giving out heterogeneous solutions.

Therefore, the combination of 2 liquids gives a new solution that could either be homogeneous or heterogeneous.

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The skeletal and balanced version of the equation would be [tex]2Na + Ca(OH)_2 --- > 2NaOH + Ca[/tex]

The symbol equation, which was otherwise referred to as skeletal equation in the illustration is an equation that expresses each participating component of a reaction in its symbolic forms.

On the other hand, a balanced equation of a reaction is the equation in which the number of atoms of different elements present in the reactants is equal to the number present in the products. It does not matter if their forms change, however.

Thus, for the equation: sodium + calcium hydroxide → sodium hydroxide + calcium

Symbol of sodium = Na

Symbol of calcium hydroxide = [tex]Ca(OH)_2[/tex]

Symbol of calcium = Ca

The equation then becomes: [tex]2Na + Ca(OH)_2 --- > 2NaOH + Ca[/tex]

The equation has taken into account the number of atoms of different elements in the reactants and the products. It is already a balanced equation.

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Answer: F

Explanation: As we move from left to right in a period, electron affinity increases due to the increases in the effective nuclear charge.

However, it will not be easier to add an electron to a smaller atom. As we move in a group from top to bottom, electron affinity decreases but flourine has the smallest size in its group. So, on adding another electron externally to the valence shell causes severe electron-electron repulsion.