Q. What phase change occurs at letter A?

Answer:

Please mark me as brainliest and also give me 5 start Thank you

Explanation:

The radioactive element neptunium (atomic number 93) has the electron configuration

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2 4d10 5p64f14 5d10 6s2 6p6 7s2 6d1 5f4

The noble gas form is

[Rn] 7s2 6d1 5f4

Answer:

carbohydrates

Explanation:

or carbon dioxide

Answer:

h and o

Explanation:

because both are non metals

Answer:

pH = 3.3

Explanation:

Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.

In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].

Solution using the I.C.E. table:

              HNO₂ ⇄    H⁺   +   KNO₂⁻

C(i)        0.55M       0M      0.75M

ΔC            -x            +x          +x

C(eq)  0.55M - x       x     0.75M + x    b/c [HNO₂] / Ka > 100, the x can be                                    

                                                             dropped giving ...

           ≅0.55M        x       ≅0.75M        

Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]

=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M

pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3

Solution using the Henderson-Hasselbalch Equation:

pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]

= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]

= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3

Answer:

Ionic compounds contain ions and are held together by the attractive forces among the oppositely charged ions

Explanation:

Common salt (sodium chloride) is one of the best-known ionic compounds. Molecular compounds contain discrete molecules, which are held together by sharing electrons (covalent bonding).

Answer:

c

Explanation:

This problem is referring to an anhydrous salt that is derive from a hydrated Epson salt (magnesium sulfate hydrate) and the atom economy is required. However, not enough information is provided, yet we can use the attached file as a reference to provide a methodology of calculation.

To begin with, we need to calculate the [tex]x[/tex] which refers to the degree of hydration of the salt, so that we use the mass before and after heating the sample to figure out the grams and subsequently moles of water that are in there:

[tex]m_w=3.648g-1.782g=1.866g\\\\n_w=0.103molH_2O[/tex]

Next, since 1.782g corresponds to the anhydrous salt, we calculate the moles in such a amount:

[tex]1.782gMgSO_4*\frac{1molMgSO_4}{120.4gMgSO_4}=0.0148mol[/tex]

Then, we divide the moles of water by those of the anhydrous salt to calculte [tex]x[/tex]:

[tex]x=\frac{0.103mol}{0.0148mol} =6.96=7[/tex]

This means the formula of the hydrate is:

[tex]MgSO_4\ 7H_2O[/tex]

Finally, for the atom economy we just divide the molar mass of the anhydrous salt by that of the hydrate:

[tex]A.E=\frac{120.4g/mol}{246.47g/mol} *100\%\\\\A.E=48.8\%[/tex]

Learn more:

Boiling point, surface tension and vapour pressure is the list that includes only bulk properties of matter.

Bulk matter refers to those materials that contains large numbers of atoms, molecules, or ions. Its can be present into all states of matter that may be solid, liquid or gas.

Boiling is a bulk process and occurs throughout the liquid as well as surface tension and vapour pressure is also bulk properties of matter so we can conclude that boiling point, surface tension and vapour pressure is the list that includes only bulk properties of matter.

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Answer:

Sunlight penetrates the top layers of the ocean, so photosynthesis occurs there.

Explanation:

The small flashlight has less inertia and smaller force is required to move it.

According to Newton's first law of motion, an object will continue at rest or in its state of uniform motion unless it is acted upon by an external unbalanced force. This is also called the law of inertia.

The quantity of mass contained in a body is a measure of its inertia. The greater the mass of the body, the greater the inertia and the greater the force required to move the body.

The smaller flashlight has less inertia than the larger flashlight, so  it takes less force to change the motion of the smaller flashlight.

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Answer:

True

ANTI MEANS AGAINST

Explanation:

Answer:

Isoelectronic means same electronic configuration as Ar. These are such as sulfide ion (S2− ), chloride ion (Cl− ) and phosphide ion (P3− ).

Explanation:

Any atom or ion with 18 electrons is isoelectronic with Ar. Some examples are:

Isoelectronic atoms or ions refer to those that possess an identical number of electrons consequently sharing the same electron configuration. The term "isoelectronic" derives from the Greek words "isos " signifying "equal " and "elektron " denoting "electron".

It is worth noting that isoelectronic atoms or ions may exhibit varying atomic numbers and charges; nonetheless, their electron count remains constant.

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Answer:

True po

Explanation:

Sana nakatutulong

#Carry on learning

Ionic compounds have higher melting and boiling point than covalent compounds, since ionic bonds are stronger than covalent bonds. Hence, we can compare the intermolecular forces using melting or boiling points.

Boiling point of a substance is the temperature at which the substance changes from liquid state to gaseous state. Melting point is the temperature at which the substance changes from solid state to liquid state.

Both melting point and boiling point depends on the bond type, molecular weight, temperature and pressure. Stronger the bond , higher energy needed to weaken the intermolecular force between molecules to convert them to liquid state or vapour state.

Hence, the temperature that have to be applied to loosen the bonds to boil them or melt them increases as bond strength increases. Therefore, these physical quantities definitely helps to infer the strength of bonds.

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It woukd decrease.

I am sure its correct you can trust me becuase I took the test.

Answer:

The speed of the wave decreases.

Explanation:

When light waves do pass through a medium, any solid, liquid, or gas, the speed of the waves actually decreases. Solids are more dense than liquids, so they decrease the speed of light even more.


(I did the quiz btw!!)

Answer:

mark me brainlest

Explanation:

Electronegativity values generally increase from left to right across the periodic table. Electronegativities generally decrease from top to bottom of a group. The highest electronegativity value is for fluorine.

Answer:

       "Electronegativity increases as you move from left to right across a period because the number of charges on the nucleus increases." (sstudy30 on Quizlet)

Explanation:

    It explains itself haha!

Have a nice day!

    I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)

- Heather

Answer:

A

Explanation:

now I'm not sure, but considering negative feedback allows the systems to self stabilize that would be the best option.

PLEASE NOTE THAT THIS IS A EDUCATED GUESS.

Answer:

snow and a cooler

Explanation:

so if its really cold out side put your drink out there.

Sorting the chemical elements in order from least reactive to most reactive, we have:

1. Fluorine (F).

2. Arsenic (As).

3. Antimony (Sb).

4. Silicon (S).

Given the following chemical elements:

Reactivity can be defined as a chemical property which determines how readily a chemical element bonds with other chemical elements, in order to form a new chemical compound.

Generally, the ability of a chemical element to bond with other chemical elements is largely (highly) dependent on the number of valence electrons it has in the outermost shell of its atomic nucleus.

As a general rule, chemical elements that are having fewer number of valence electrons are the most reactive while those having higher valence electrons are least reactive.

Also, chemical reactivity decreases down a group on the periodic table.

Based on the periodic table, the valency for the given chemical elements are:

In conclusion, sorting the chemical elements in order from least reactive to most reactive, we have:

1. Fluorine (F).

2. Arsenic (As).

3. Antimony (Sb).

4. Silicon (S).

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Answer:

43.7mol

Explanation:

[tex]?mol = 7.86kg * \frac{1000g}{1kg} *\frac{1mol}{180g}[/tex]

Above is dimensional analysis method. Write what you are trying to find with the question mark and write your given info on the other side of the equal sign. Follow the units and pay attention to them cancelling out. You should have your answer unit by the end.

the 180g came from the table with masses times the chemical formula all added together. Below is exact formula.

hydrogen mass(hydrogen amount) + carbon mass(carbon amount) + oxygen mass(oxygen amount)

1g(8)+12g(9)+16g(4)=180g

180g is 1 mole of [tex]C_{9} H_{8} O_{4}[/tex]

Answer:

see explanation

Explanation:

Break down the following equations into two half equations(One for oxidation, one or reduction )

1. Cu + 2Ag+ ➡️Cu2+ +2Ag

2. Cl2 +2I- ➡️I2 + 2Cl​-

in reaction "1", the copper is being oxidized from 0 to +2 by losing 2 electrons

Cu---->Cu2+   + 2e-in reaction "2

in reaction "1" the silver is being reduced by gaining those 2 e-.

2Ag1+  + 2e----------->2Ag

In reaction "2", the iodine is being oxidized by losing 2 e-

2I- -------------> I2 + 2e

In reaction "2" the chlorine is being reduced by gaining those 2 e

Cl2 + 2e------------> 2Cl-

To solve such this we must know the concept of redox reaction. Therefore, the half reaction for the given reactions can be written as

1. Cu + 2Ag⁺ [tex]\rightarrow[/tex]Cu²⁺ +2A

Cu [tex]\rightarrow[/tex]Cu²⁺   + 2e⁻

2Ag⁺ + 2e⁻[tex]\rightarrow[/tex]2Ag

2.Cl[tex]_2[/tex]+2I⁻ [tex]\rightarrow[/tex]I[tex]_2[/tex] + 2Cl​⁻

2I⁻[tex]\rightarrow[/tex] I[tex]_2[/tex] + 2e⁻

Cl[tex]_2[/tex] + 2e⁻-----------> 2Cl⁻

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.

Redox reaction is a chemical reaction where oxidation and reduction takes place simultaneously. Oxidation is loss of electrons and reduction is gain of electrons. The electron transfer from oxidant to reductant.

1. Cu + 2Ag⁺ [tex]\rightarrow[/tex]Cu²⁺ +2A

Cu [tex]\rightarrow[/tex]Cu²⁺   + 2e⁻

2Ag⁺ + 2e⁻[tex]\rightarrow[/tex]2Ag

2.Cl[tex]_2[/tex]+2I⁻ [tex]\rightarrow[/tex]I[tex]_2[/tex] + 2Cl​⁻

2I⁻[tex]\rightarrow[/tex] I[tex]_2[/tex] + 2e⁻

Cl[tex]_2[/tex] + 2e⁻-----------> 2Cl⁻

Therefore, the half reaction for the given reactions can be written as above.

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Answer:

Elisa is always tired because her cells arent producing enough sugars also know as glucose forher body. another way to write out glucose is to use its equation C6H12O6.

Explanation:

Students figure out: Elisa feels tired because her cells aren't getting the molecules they need from food and air, which are necessary for her cells to function, grow, and repair. ... Students figure out: Elisa's cells are getting enough oxygen and amino acids, but not enough glucose

Answer:

less

Explanation:

An electron has a charge of -1 so if there are more electrons than protons the overall charge of the atom is going to be negative

Answer:

Amino acids are molecules that combine to form proteins.

Explanation:

Amino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids to make proteins to help the body: ... Repair body tissue.

Hope this helps :)

Answer:

An open system can exchange both energy and matter with its surroundings. The stovetop example would be an open system, because heat and water vapor can be lost to the air.

Explanation:

Answer:

0.296 M

Explanation:

What is the molar concentration of a solution prepared by dissolving 3.05 grams of sodium acetate in enough water to prepare 3.43 x 102 mL of the solution

sodium acetate NaCH3COO has molar mas of

23 + 12 +24 + 1 +32 = 92 g/mol

3.05 g is 3.05 g/ 92 g/mol = 0.0328 moles

it is distributed over 102 mL = 0.102 L

its concentration is 0.0328/ 0.102 =0.296 M Mhttps://brainly.com/question/25586315?answering=true&answeringSource=feedPublic%2FhomePage%2F3#

Answer:

a measure of hotness or coldness expressed in terms of a scale like Fahrenheit or Celcius

Answer:A

Explanation: I’m pretty sure