How many moles of helium are 8.84×10^24 atoms of He?

Answer:

1.146 x 10⁴ year.

Explanation:

kt = ln [A₀]/[A]

k is the rate constant = 1.21 x 10⁻⁴ year⁻¹.

t is the time = ??? years.

[A₀] is the initial percentage of carbon-14 = 100.0 %.

[A] is the remaining percentage of carbon-14 = 1/4[A₀] = 25.0 %.

∵ kt = ln [Ao]/[A]

∴ (1.21 x 10⁻⁴ year⁻¹)(t) = ln (100.0%)/[25.0 %]

(1.21 x 10⁻⁴ year⁻¹)(t) = 1.386.

∴ t = 1.386/ (1.21 x 10⁻⁴ year⁻¹) =  1.146 x 10⁴ year.

The piece of fossilized wood is approximately 11,460 years old, based on its carbon-14 radioactivity being 1/4 that of new wood and using the known half-life of carbon-14 which is 5730 years.

A fossilized piece of wood has a carbon-14 radioactivity that is 1/4 that of new wood. Given that the half-life of carbon-14 is 5730 years, we can estimate the age of the fossil. For each half-life that passes, the amount of carbon-14 halves. If the wood has 1/4 the radioactivity, this means that two half-lives have passed, as (1/2)² = 1/4. Therefore, using the formula for carbon dating and the known half-life of carbon-14, we can calculate that the wood is approximately 2 times 5730 years old, which is 11,460 years old.

Answer:solid

liquid

gas

supercritical fluid

plasma

superfluidity in liquid helium (that is Bose-Einstein condensate property)

supersolidity in fermionic condensate like the potassium40

Hope this helps and i like your profile pic ;)

The five phases of matter are solids, liquids, gases, plasma, and Bose-Einstein condensates.

Each phase differs in the way its atoms and molecules behave and interact with one another, resulting in different properties and behaviors.

Here's a brief explanation of each of the five phases of matter:

Solids: Solid matter has a definite shape and volume. It is rigid and cannot be compressed.

Liquids: Liquid matter has a definite volume but takes the shape of the container it's in. It can flow and be poured.

Gases: Gaseous matter has neither a definite shape nor a definite volume. It can be compressed and expanded.

Plasma: Plasma is a high-energy state of matter in which atoms lose their electrons, resulting in a mix of free electrons and positively charged ions. It is the most common state of matter in the universe.

Bose-Einstein Condensates: Bose-Einstein condensates are formed at extremely low temperatures when a group of atoms behaves like a single entity, becoming indistinguishable from one another.

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Answer:

According to libretexts the answer would be B. decreases.

Explanation:

If the hydrogen concentration increases, the pH decreases, causing the solution to become more acidic. This happens when an acid is introduced. ... If the hydrogen concentration decreases, the pH increases, resulting in a solution that is less acidic and more basic

Answer:

The answer is B: it Decreases

Answer:

The concentration of OH- ions = 6.31*10⁻³M

Explanation:

Given:

pH of ammonia solution = 11.8

Formula:

[tex]pH + pOH = 14\\\\pOH = 14-pH = 14 - 11.8 = 2.2\\\\pOH = -log[OH-]\\[/tex]

[tex][OH-] = 10^{-pOH } = 10^{-2.2}  = 6.31*10^{-3} M[/tex]

The concentration of OH- ions in a solution with a pH of 11.8 is 6.31 times 10⁻³ M. The calculation involves finding the pOH and then the antilog of the negative pOH.

The pH of a solution is a measure of its acidity or basicity. For a solution with a pH of 11.8, we can find the concentration of hydroxide ions (OH-) by first calculating the pOH, which is 14.00 (at 25°C) minus the pH value. Therefore, the pOH is 14.00 - 11.8 = 2.2. The concentration of OH- is then found by taking the antilog (base 10) of the negative pOH: [OH-] =[tex]10^{ -pOH }[/tex]= 10⁻²°².

To calculate this, we get 10⁻²°² = 6.31 times 10⁻³ M, meaning the concentration of OH- in the solution is 6.31 times 10⁻³M.

Answer:

[tex]\boxed{\text{6.00 mol/L}}[/tex]

Explanation:

(a) Balanced equation

2HCl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O  

(b) Moles of Ca(OH)₂

[tex]\text{Moles of base} = \text{2.00L} \times \dfrac{\text{1.50 mol}}{\text{1 L}} = \text{3.000 mol base}[/tex]

(c) Moles of HCl

[tex]\text{Moles of HCl} = \text{3.000 mol base} \times \dfrac{ \text{2 mol HCl}}{\text{1 mol base}} = \text{6.000 mol HCl}[/tex]

(d) Molar concentration of HCl

[tex]\text{Molar concentration} = \dfrac{\text{moles of solute}}{\text{litres of solution}}\\\\c = \dfrac{ n }{ V}\\\\c= \dfrac{ \text{6.000 mol}}{ \text{1.000 L}} = \text{6.00 mol/L}[/tex]

The molar concentration of the HCl was [tex]\boxed{\textbf{6.00 mol/L}}[/tex]

Answer:

B. 0.2.

Explanation:

n = mass/molar mass

mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.

∴ n = mass/molar mass = (20 g)/(100.0869 g/mol) = 0.1998 ≅ 0.2 mol.

So, the right choice is: B. 0.2.

Final answer:

To find the total number of moles in 20 grams of CaCO₃, calculate the molar mass of CaCO₃ and then use the formula for moles. The total number of moles in 20 grams of CaCO₃ is 0.2.

Explanation:

To calculate the total number of moles represented by 20 grams of CaCO₃, we first need to determine the molar mass of CaCO₃.

The molar mass of CaCO₃:

Ca: 40.08 g/mol

C: 12.01 g/mol

O: 16.00 g/mol

Adding these up gives a total molar mass of CaCO₃ as 100.09 g/mol.

Now, we use the formula:

Number of moles = Mass / Molar mass

Number of moles = 20 g / 100.09 g/mol = 0.2 moles

Therefore, 20 grams of CaCO₃ represents 0.2 moles.

Answer:

[tex]\boxed{\text{66.2 A}}[/tex]

Explanation:

1. Write the equation for the reaction.

M_r:                 24.30

          MgCl₂ ⟶ Mg + Cl₂

m/g:                   60.0

2. Calculate the moles of Mg

Moles of Mg = 60.0 g Mg × (1 mol Mg/ 24.30 g Mg) = 2.469 mol Mg

3. Calculate the moles of electrons

Moles of electrons = 2.469 mol Mg × (2 mol electrons/1 mol Mg)

= 4.938 mol electrons

4. Calculate the number of coulombs

Q = 4.938 mol electrons × (96 485 C/1 mol electrons) = 476 500 C

5. Calculate the current required

Q  = It

I = Q/t

t = 2.00 h × (60 min/1h) × (60 s/1 min) = 7200 s

I = 476 500 C/7600 s= 66.2 C/s = 66.2 A

You need a current of [tex]\boxed{\textbf{66.2 A}}[/tex].

The answer would be true

Final answer:

The statement is false because elements in family VIA (Group 16) of the periodic table typically form anions with a -2 charge, not a +6 charge, as they tend to gain two electrons to achieve a noble gas electron configuration.

Explanation:

The statement that the anions formed from the atoms of the elements in family VIA should carry a +6 charge is false. Elements in Group 16 (family VIA) of the periodic table, also known as the chalcogens, include oxygen, sulfur, selenium, tellurium, and polonium. These elements typically have six valence electrons and tend to gain two electrons to achieve a stable electron configuration, similar to that of a noble gas. As a result, these elements form anions with a -2 charge, not a +6 charge.

An easy way to remember the typical charge of anions in this group is by considering the general trend on the periodic table: as you move from the right to the left, elements form anions with a negative charge equal to the number of groups moved left from the noble gases. Therefore, since Group 16 is two groups left of the noble gases, the typical anion charge for these elements would be 2-.

Your answer would be D

Statement which is true  about ionic compounds is that it is composed of anions and cations and yet it is electrically neutral.

Ionic compound  or electrovalent compound is a type of compound  which is formed between two elements when there is an exchange of electrons which takes place between  the atoms resulting in the formation of ions.

When the atom looses an electron it develops a positive charge and forms an ion called the cation while the other atom gains the electron and develops a negative charge  and forms an ion called the anion.

As the two atoms are oppositely charged they attract each other which results in the formation of a bond called the ionic bond and the compound possessing the bond is called the ionic compound.

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Answer:

Explanation:

The transfer of energy as heat, i.e. heat transfer, is the transfer of kinetic energy due to difference in temperatures of the bodies: heat is transferred from warmer objects to cooler obects.

This heat transfer may occur by three different means:

Conduction is the transfer of heat between objects in direct contact and is due to the transfer of kinetic energy among neighbour particles (atoms or molecules) which are in constant vibration and colliding one to each other. The hotter particles are vibrating faster than the cooler ones, and, so, during the collisions the faster particles trasfer kinetic energy to the quiter particles.

For example, when you heat the tip of a needle the heat will be transfered from the tip to the rest of the needle by conduction.

Convection is the transfer of heat by the motion of fluids (gases or liquids), again the hotter particles, which have greater kinetic energy, transfer their energy to the cooler particles, but in this case the fluid moves.

Radiation is the heat transfer by electromagnetic waves; again from hotter objects to cooler ones. Since electromagnetic waves travel through vacumm, radiation does not need a physical medium.

Conduction is the process by which energy is transferred as heat through the direct contact of molecules, facilitated by atomic or molecular collisions due to differing temperatures. This transfer of heat can change the temperature, affecting things from everyday life to global weather, demonstrating the essential role of conduction in understanding our world.

The process of energy being transferred as heat through the collision of molecules is called conduction. Conduction is a fundamental concept in physics and it involves the direct transmission of heat through a substance due to a difference in temperature. It is facilitated by atomic or molecular collisions and it occurs when there is a connection or contact surface between high temperature and low temperature regions.

For example in Figure 1.21 it illustrates how molecules, each having different kinetic energies resulting from their respective temperatures, collide and transfer energy. A molecule in the lower-temperature region gains energy after the collision  while a molecule in the higher-temperature region loses energy.

This transfer of heat might change the temperature and is a central concept in thermodynamics playing a critical role in everything from everyday cooking to industrial processes. Therefore understanding conduction is essential to understanding the world around us, from weather patterns on Earth to the life cycle of stars.

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Answer:

Arrhenius theorized that a base is a chemical compound that contains hydroxide ions (OH⁻) and ionizes in water releasing them.

Explanation:

Svante Arrhenius was the first scientist to theorize about acids and bases.

Arrhenius' acid  base theory states that an acid is a compound that contains hydrogen atoms and ionizes in water to produce hydrogen ions (H⁺), and a base is a compound that contains hydroxide ions (OH⁻) that are released in water.

These are some examples of compounds which can be named as acid or base following Arrhenius' theory:

This theory is limited because it does not include compounds that do not contain or ionizes producting H⁺ or OH⁻. E.g. NH₃, which is a base (according to other theory).

Arrhenius theorized that a base is a chemical compound that dissolves in water to yield hydroxide anions (OH-) or absorbs hydrogen ions (H+) in a solution, thereby reducing acidity. The strength of a base depends on how readily it releases its hydroxide ions or absorbs hydrogen ions. Stronger bases release more hydroxide ions leading to higher pH.

According to Arrhenius's theory, a base is a chemical compound that dissolves in water to yield hydroxide anions (OH-). For example, bases like ammonia can chemically react with water and release hydroxide ions in solution. Besides, a base can also absorb hydrogen ions (H+), present in the solution, resulting in reduced acidity.

The strength of a base is measured by how readily it releases its hydroxide ions or absorbs hydrogen ions. For instance, strong bases liberate most or all of their hydroxide ions, whereas weak bases release only some hydroxide ions or absorb only a few hydrogen ions.

These bases, such as bicarbonate (HCO3-), can form water molecules by combining with the H+ ions in a solution, thereby reducing the solution's acidity and raising the pH. On the other hand, stronger bases like Sodium hydroxide tend to readily donate OH-, leading to higher pH.

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Answer:

The atom is oxidized is Ca.

Explanation:

Ca + Cl₂ → CaCl₂,

Ca loses 2 electrons and is oxidized to Ca²⁺. (Ca → Ca²⁺ + 2e).

Cl is gains 2 electrons in "Cl₂, oxidation state zero" and is reduced to Cl⁻. (Cl₂ + 2e → 2Cl⁻).

Answer:

Carbon

.. Both graphite snd diamond are carbon containing elements

Carbon is present in both diamond and graphite.

The allotropes of carbon are called as Graphite and diamond. These minerals synthetically comprise of carbon molecules with various physical properties. These minerals, when all in options, are referred to be as polymorphs, having a similar kind of science, however of the different crystalline structures.  

In these allotropes of carbon, the molecules comprising of carbon atoms in that of the Diamond and Graphite, are bound together by solid covalent bonds with various courses of action.  

Valuable stone and graphite have move structures which speak to their assorted properties, and both are unadulterated carbon. In any case, the graphite's particles join to the three atoms of carbon and get related with the plates that are parallel to one another. The particles of Diamond enter the four atoms of carbon in an outline.

Answer:

[tex]\boxed{\text{10.7 ng}}[/tex]

Explanation:

Let A₀ = the original amount of ⁵⁵Co .

The amount remaining after one half-life is ½A₀.

After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.

After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.

The general formula for the amount remaining is:

A =A₀(½)ⁿ

where n is the number of half-lives

n = t/t_½

Data:

   A = 1.90 ng

    t = 45 h

t_½ = 18.0 h

Calculation:

(a) Calculate n

n = 45/18.0 = 2.5

(b) Calculate A

1.90 = A₀ × (½)^2.5

1.90 = A₀ × 0.178

A₀ = 1.90/0.178 = 10.7 ng

The original mass of ⁵⁵Co was [tex]\boxed{\text{10.7 ng}}[/tex].

Answer:

The missing nucleus is carbon-12:

Explanation:

The nuclear reaction given is:

[tex]^{249}_{98}Cf[/tex] + ___ → [tex]^{257}_{104}Rf+4^1_0n[/tex]

To balance this equation you must add a nucleus which contains the missing mass and atomic numbers.

Mass number is the number of protons plus neutrons and is the superscript to the left of the chemical symbol: 249 for Cf, 257 for Rf, and 1 for n (neutron).

Atomic number is the number of protons and is the subscript to the left of the chemical symbol: 98 for Cf, 104 for RF and 0 for n.

Thus, the balance is:

Mass number:

Atomic number:

Then, you are looking for a nucleus (or gropu of nuclei) which supply 6 protons and 6 neutrons. That is a nucleus of carbon-12: [tex]^{12}_6C[/tex].

The balanced nuclear reaction is:

[tex]^{249}_{98}Cf+^{12}_{6}C[/tex] → [tex]^{257}_{104}Rf+4^1_0n[/tex]

The question is about balancing a nuclear equation. The missing nucleus in the nuclear reaction 249/98Cf + ____ -----> 257/104Rf + 4 1/0n is Carbon-8 (8/6C) determined by conserving atomic number and atomic mass.

The problem you have is a nuclear equation specifically a type of nuclear reaction called alpha decay, where an element transforms into a new element and emits an alpha particle. In your problem Californium-249 (249/98Cf) decays into Rutherfordium-257 (257/104Rf) and four neutrons (1/0n). So in order to balance the nuclear equation we need to find out which nucleus reacts with Californium-249 to produce Rutherfordium-257 and four neutrons.

This can be done by looking at the difference in the atomic numbers and atomic masses on either side of the equation. We know that the atomic number (the number of protons) and atomic mass (the number of protons + neutrons) must be conserved during a nuclear reaction.

Here the atomic number goes from 98 on the left side of the equation (the Californium) to 104 on the right side (the Rutherfordium). Therefore, the difference 6 is the atomic number of the missing nucleus. The atomic mass goes from 249 (Californium) to 257 (Rutherfordium) so the difference 8 is the atomic mass of the missing nucleus. Thus, the missing nucleus is Carbon-8, or 8/6C.

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Answer:

B.the velocity for the forward reaction equal that of the reverse reaction

Explanation:

A state of rest or motion of a system is described as equilibrium.

For a system to be in equilibrium, the following conditions must be met:

1. It must be involved in reversible chemical process no matter how small the extent of the reversibility.

2. The rate of forward process is equal to the rate of backward or reverse process.

3. The system must be closed.

4. There is no change in the concentration of each of the species in equilibrium with respect to time. There must be a constancy of concentration of each species in the equilibrium process.

When we change any of the conditions of equilibrium, the Le Chatelier's principle comes into play.

The principle states that "if any of the conditions of a system in equilibrium is changed, the system will adjust itself in order to annul the effect of the change".

Answer:

B.the velocity for the forward reaction equal that of the reverse reaction

Explanation:

A reversible reaction proceeds in a closed system. Equilibrium is only attainable in a closed system. When a reaction occurring in a closed system attains equilibrium, the rate(velocity) of the forward reaction will be exactly the same as the rate (velocity) of the reverse reaction.

This implies that the forward and reverse reactions proceed at the same rate.

Answer:

= 1.44 L

Explanation:

Molarity or concentration is given by the formula;

Molarity = moles/volume in L

Therefore;

Volume = moles/molarity

Number of moles = 0.180 moles

Molarity = 0.125 M

Thus;

Volume = 0.18 mol/ 0.125 M

             = 1.44 L

             = 1.44 L

Final answer:

The correct answer to the question is B. The atoms of the reactants combine to form a new substance, and in the case of hydrogen and oxygen gases, they react to form liquid hydrogen peroxide with different chemical properties.

Explanation:

When hydrogen gas and oxygen gas react to form liquid hydrogen peroxide, the atoms of the reactants combine to form a new substance. This is because a chemical reaction involves the rearrangement of atoms to produce new substances with different chemical properties.

The correct statement about this reaction is: B. The atoms of the reactants combine to form a new substance. In a chemical reaction such as this, the physical and chemical properties of the products are typically different from those of the reactants.

An example of a simple chemical reaction is the decomposition of hydrogen peroxide into water and oxygen.

This reaction can be represented by the balanced equation 2H₂O₂ (hydrogen peroxide) → 2H₂O (water) + O₂ (oxygen), showing that hydrogen peroxide and water are compounds composed of more than one type of element, while molecular oxygen is a homonuclear molecule but not a compound

Answer:

Alkane

Explanation:

Definition of Alkane "any of the series of saturated hydrocarbons including methane, ethane, propane, and higher members. (google dictionary)"

CH4 is methane.

Answer:

Redox reactions

Explanation:

Redox reactions consists of both oxidation and reduction

one species gets oxidised and other species become reduced, both oxidation and reduction happen simultaneously

reduction is either gain of electrons or gain of hydrogen. in reduction the oxidation number of species reduces

in this reaction the reduction half equation is

O₂ + 4e --> 2O²⁻

oxidation is either loss of electrons or gain of oxygen. in oxidation the oxidation number of species increases.

Fe --> Fe²⁺ + 2e

since both these half reactions happen overall its a redox reaction

Answer:

The cyanide ion is a strong nucleophile.

Explanation:

Strong acids

Strong acids like hydrochloric and sulfuric acid dissociate completely in solution.

[tex]\underbrace{\hbox{HCl }}_{\hbox{strong acid}} + {\text{ H$_{2}$O }} \longrightarrow \text{H}_{3}\text{O}^{+}+ \underbrace{\hbox{Cl^{-}}}_{\hbox{weak nucleophile}}[/tex]

Because they are strong acids, their conjugate bases are extremely weak bases/nucleophiles.

Thus, they can protonate the carbonyl oxygen, but the conjugate bases cannot act as nucleophiles.

Weak acids

Weak acids like HCN dissociate only slightly in solution.

[tex]\underbrace{\hbox{HCN}}_{\hbox{weak acid}} + {\text{ H$_{2}$O }} \rightleftharpoons \text{H}_{3}\text{O}^{+}+ \underbrace{\hbox{:CN^{-}}}_{\hbox{strong nucleophile}}[/tex]

Because HCN is a weak acid, its conjugate base is a strong nucleophile.

Thus, it generates relatively few hydronium ions, but the cyanide ion is a strong nucleophile that can attack the partially positive carbon and form the cyanohydrin.

RCH=O + CN⁻ ⟶ RCH(CN)O⁻ ⟶ RCH(CN)OH

As the CN⁻ ions react with the aldehyde or ketone, they are removed from solution.

According to Le Châtelier's Principle, more HCN dissociates to replace the CN⁻ ions, and the reaction goes nearly to completion.

Aldehydes and ketones react with hydrogen cyanide because it provides cyanide ions that act as nucleophiles in a nucleophilic addition reaction to form cyanohydrins; strong acids don't provide such nucleophiles and instead only protonate the carbonyl group.

The reason why aldehydes and ketones react with a weak acid like hydrogen cyanide (HCN) but not with strong acids such as HCl or H2SO4 lies in the mechanism of nucleophilic addition reactions. In the presence of a strong acid, the carbonyl group of aldehydes or ketones is protonated, making the carbon even more electrophilic but without providing a good nucleophile. HCN, being a weak acid, partially dissociates in the presence of a strong base to form cyanide ions (CN-), which are good nucleophiles and can attack the carbonyl carbon to form cyanohydrins. The reaction requires slightly acidic conditions (pH around 4-5) to optimize the rate, as too much strong acid would suppress the producing of cyanide ions necessary for the nucleophilic addition.

Aldehydes and ketones react with weak acids like hydrogen cyanide (HCN) because they can form cyanohydrins through nucleophilic addition reactions. In this reaction, the weak acid HCN is converted into the cyanide ion (CN-) by a small amount of a strong base. The cyanide ion then attacks the carbonyl carbon of the aldehyde or ketone, resulting in the formation of a cyanohydrin. This reaction requires a basic catalyst and is favored for aldehydes and unhindered ketones.

To find the ionization potential of an atom, you use the wavelength of light that causes the matter to ionize. This can be calculated using the Planck-Einstein relation where energy equals Planck's constant multiplied by light's frequency. Frequency is found using the speed of light equation which is then used in the Planck-Einstein equation to find the ionization potential.

The question is asking for the ionization potential of a helium atom. Ionization potentials denote the energy required to remove an electron from an atom. It's given that the minimum wavelength of light that can ionize helium is 50.4 nm. The energy of a photon of light can be calculated using the Planck-Einstein relation, E=hν, where h is Planck's constant (6.626 x 10-34 Js) and ν is the frequency of the light. The frequency can be found from the speed of light equation, c=λν, rearranged to give ν=c/λ.

Substituting constants and the given wavelength, and converting m to nm:

ν = (3.00 x 108 m/s) / (50.4 x 10-9 m)

Therefore, E = (6.626 x 10-34 Js) x ν

This would yield the energy needed to ionize the helium atom and that value is the ionization potential of helium in Joules.

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A soluble ionic compound in aqueous form will be able to 4. conduct current

An aqueous ionic compound is able to conduct current because:

As a result of being able to move around in a solution, the ions of aqueous compound will be able to carry electricity from one point to another and so will be able to conduct electricity.

In conclusion, aqueous solutions of ionic compounds can conduct current.

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Answer:

4. conduct current

Final answer:

Amperage or current flow, can be thought of as a faucet being turned on and water flowing. Option d

Explanation:

The correct answer to the student's question is d. Amperage. The analogy of a faucet turning on and water flowing is used to describe electric current. Electric current can indeed be thought of similarly to water flowing through a pipe for its easy visualization. When we talk about the flow of charge in a circuit, we use the term amperage to quantify it.

The SI unit for electric current, or amperage, is the ampere, which is defined as one coulomb of charge passing through a point in one second (1A = 1C/s).

This means that electric current, or amperage, is the rate at which the electrical charge is flowing. In electric circuits, this is akin to water moving through a piping system, where the current is the same at all points in the circuit, including inside any batteries or resistors.

This flow of charge is crucial for the functioning of electrical appliances and is measured and regulated for safety and efficiency using devices like fuses and circuit breakers which are rated in amperes. Option d

object in motion tends to be in motion unless acted upon by an external force

Answer:

The answer is A) objects in motion tend to stay in motion unless acted upon by an outside force

Explanation:

Newton's laws of motion are three laws that describe the relationship between forces acting on an object and the motion of that object. Newton's first law of motion states that an object that is at rest or in uniform motion tends to stay at rest or in uniform motion, respectively, until acted upon by an outside force.

It is B. What I found is when water freezes it's entropy decrease. If water freezing that means the temperature is decreasing and that is B.

I believe it’s C......

it should be c <3 lol hahahahaahaa

Pressure, defined as the normal force per unit area, increases when the surface area decreases while the force is constant. This is based on the equation of pressure (P=F/A) and can be largely observed in fluid dynamics, for instance, within conduits with decreasing cross-sectional areas.

Pressure is defined as the normal force per unit area exerted on a surface by a fluid or gas, or the force exerted perpendicularly on a surface. An important characteristic of pressure is that it acts uniformly in all directions at a single point in a fluid. This is also known as Pascal's Principle.

According to the equation P=F/A, where P is pressure, F is the force, and A is the area, pressure increases when surface area decreases, given that the force is held constant. This is simply because as the denominator in a fraction decreases, the overall value of the fraction increases. Therefore, if the surface area decreases with a constant force, the pressure consequently increases.

The phenomenon can be observed largely in fluid dynamics. For example, in pipes or any other fluid-carrying conduits where the cross-sectional area decreases, the pressure tends to increase due to the conservation of the flow rate (continuity equation). When the tube narrows, fluid speed increases and pressure decreases. Similarly, a decrease in the area of a compressed gas container while keeping the force (temperature) constant results in the compression of gases, thereby increasing their pressure.

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The answer is B.) benzaldehyde sorry if I’m wrong

Answer: Option (b) is the correct answer.

Explanation:

In the given structure a benzene molecule, that is, [tex]C_{6}H_{5}[/tex] is attached. And, further an aldehyde group that is, CHO group is attached to the benzene molecule.

Hence, suffix "aldehyde" will be added to the name of this molecule.

Whereas a group with formula [tex]C_{6}H_{5}OH[/tex] is known as phenol.

Therefore, we can conclude that the name of this given compound is benzaldehyde.

Answer:

3.925 mol.

Explanation:

2 Na₂O₂(s) + 2 H₂O(l) → 4 NaOH(s) + O₂(g) ,

It is clear that 2 moles of Na₂O₂ react with 2 moles of H₂O to produce 4 moles of NaOH and 1 mole of O₂ .

Using cross multiplication:

4 moles of NaOH produced with → 1 mole of O₂ .

15.7 moles of NaOH produced with → ??? mole of O₂ .

∴ The no. of moles of O₂ made = (1 mole)(15.7 mole)/(4 mole) =  3.925 mol.

When 15.7 moles of sodium hydroxide are produced, 3.925 moles of oxygen gas will be made, using the 4:1 mole ratio between NaOH and O2 from the balanced chemical equation.

To determine how many moles of O2 will be made when 15.7 moles of sodium hydroxide are produced, we use the stoichiometric relationship from the balanced chemical equation provided.

According to the balanced equation:

2 Na2O2(s) + 2 H2O(l) → 4 NaOH(s) + O2(g)

For every 4 moles of NaOH produced, 1 mole of O2 is produced. This suggests a 4:1 ratio between NaOH and O2.

To find the number of moles of O2 produced, we set up a ratio:

(15.7 moles NaOH) × (1 mole O2 / 4 moles NaOH) = 3.925 moles O2

Therefore, when 15.7 moles of sodium hydroxide are produced, 3.925 moles of oxygen gas are produced.