Which of the following is a sign a chemical reaction has occurred?

Answer:

The first law means that unless a force pushes or pulls the object will stay completely motionless. The second law says that acceleration depends on the amount of force exerted on an object and the objects mass. The third law means that if a force of 50 Newtons to the left occurs, a force of 50 Newtons to the right will also occur.

Explanation:

Answer:

Explanation:

Ist law: A body will continue in its present state of rest or if it is in motion, will continue to move with uniform speed on a straight line unless it acted upon by a force

2nd law: The rate of change of momentum of a body is directly proptional to the applied force and takes place in the direction of the force. F = ma

3rd law: To every action, there's an equal and opposite reaction.

Answer:

Mass and energy can convert to one another

Explanation:

The mathematical expression E = mc² is known as the Einstein equation. Here:

E= energy

m = mass

c = velocity of light.

The equation shows that mass and energy are inter-convertible and they relate to one another. It implies that a given mass would have an equivalent amount of energy it can produce or generate and also vice versa. We also see that energy is also associated with mass. This equation is very useful in understanding nuclear reactions.

Answer:

Mass and energy can convert to one another

Explanation:

c=λν

3*10^8 m/s * 10^9 nm/m / 7.26*10^14 s^-1= λ

=413.22 nm

λ=413 nm

Answer : The wavelength of violet light is, 413 nm

Explanation :

Formula used :

[tex]\nu=\frac{c}{\lambda}[/tex]

where,

[tex]\nu[/tex] = frequency of violet light = [tex]7.26\times 10^{14}Hz=7.26\times 10^{14}s^{-1}[/tex]

As we know that, [tex]Hz=s^{-1}[/tex]

[tex]\lambda[/tex] = wavelength of violet light

c = speed of light = [tex]3.00\times 10^8m/s[/tex]

Now put all the given values in the above formula, we get:

[tex]7.26\times 10^{14}s^{-1}=\frac{3.00\times 10^8m/s}{\lambda}[/tex]

[tex]\lambda=\frac{3.00\times 10^8m/s}{7.26\times 10^{14}s^{-1}}[/tex]

[tex]\lambda=4.13\times 10^{-7}m=4.13\times 10^{-7}\times 10^9nm=413nm[/tex]

conversion used : [tex]1m=10^9nm[/tex]

Therefore, the wavelength of violet light is, 413 nm

Answer:

Kinetic energy

Explanation:

Objects or particles under motion posses energy in the form of kinetic energy which is directly proportional to the square of the velocity of the given particle.

E= 1/2mv² where m is the mass of the particle and v the velocity of the particle.

Answer:

(C) Kinetic

Explanation:

2020

Answer:

1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^3 = Vanadium or V

Explanation:

Do Remember there are two states for an Electron Configuration.

Excited and Ground

For brevity

Ground State Electron Configuration:

Naturally, atoms use the lowest energy possible, and this state in which an atom is at the lowest energy level possible is the Ground State.

Final answer:

The ground state electron configuration for vanadium (V) is [Ar] 4s² 3d³, as V follows the 3d orbital filling sequence after Ca and before Cr with its half-filled 3d5-shell.

Explanation:

The ground state electron configuration for the element vanadium (V), which has the atomic number 23, is a topic related to the transition elements in chemistry. The electronic configuration for vanadium can be tricky due to the closeness in energy levels of the 4s and 3d orbitals. However, from the given reference information and understanding the sequence of orbital filling for transition elements, we can deduce that after potassium (K) and calcium (Ca), where the 4s orbital is filled, the 3d electrons begin to be filled for scandium (Sc), titanium (Ti), and then vanadium (V). Keeping in mind the discontinuity that occurs at chromium (Cr), vanadium's ground state configuration can be written using the knowledge that V comes just before Cr. Therefore, vanadium’s electron configuration is [Ar] 4s² 3d³, following the 3d orbital filling after Ca and before the half-filled 3d5-shell configuration of Cr.

Answer

Actually it is C

Explanation:

Thanks comment in the prevoius answer. Im doing study island now

Answer:

1 mole of gas = 22.4L

2.5 moles of gas takes up = ( 22.4 L/ 1 mole ) x 2.5 mole

= 56 L

Explanation:

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The volume of 2.5 moles of nitrogen gas (N2) at standard temperature and pressure (STP) is 56 liters.

The question asks about the volume of 2.5 moles of nitrogen gas (N2) at standard temperature and pressure, commonly referred to as STP.

At STP, one mole of any gas occupies 22.4 liters. This is known as molar volume. Therefore, we can calculate the volume that the specified moles of nitrogen gas would occupy by multiplying the quantity in moles by the molar volume.

Consequently, the volume of 2.5 moles of nitrogen gas at STP would be: 2.5 moles * 22.4 L/mole = 56 L

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Answer:

She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.  

Explanation:

A supersaturated solution contains more salt than it can normally hold at a given temperature.

A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.

Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.

B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.

C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.

B just took test and got the correct answer.

Answer:

The average atomic mass is 24.30 amu.

Explanation:

When there are at least 2 isotopes for an atom, each with its own atomic mass, we can calculate an average atomic mass (AAM), which considers the mass of each isotope and its relative abundance. The mathematical expression is:

[tex]AAM=\frac{\Sigma m_{i} \times ab_{i}  }{\%100}[/tex]

where,

AAM is the average atomic mass

mi is the mass of each isotope

abi is the relative abundance of each isotope

If we replace this expression with the data we have, then:

[tex]AAM=\frac{23.9850amu \times 78.99 \% + 24.9858amu \times 10.00\% + 25.9826amu \times 11.01 \%}{100\%} =24.30amu[/tex]

Answer:

Option D.

Explanation:

Some of the alpha particles Rutherford shot at the gold foil bounced back; some went all over the place, but the majority of them went right through. That meant there had to be some sort of positively charged subatomic particle in there, but it had to be at the center and couldn't take up a lot of room.

Answer:

       when the pressure is decreased, the temperature of both containers will increase (option D).

Explanation:

Since this question has only one answer, you must assume that both containers are identical, i.e. have the same volume.

Using the ideal gas equation pV = nRT you can conclude that pressure and temperature are directly related, i.e. if the pressure is decreased, the temperature will decrease proportionally, which is opposite to the assumption that when the pressure is decreased, the temperature of both containers will increase.

On the other hand, from the same equation, you can tell the relationship between the other variables and conclude that the other choices are valid assumptions:

A. when the temperature is increased, the volume of both containers will increase:

Correct: pV = nRT shows that volume and temperature are directly related: when T increase, V increase)

B. when the pressure is increased, the volume of both containers will decrease

Correct: pV = nRT shows that p and V and inversely related, so when p is incrased, V will decrease.

C. both containers contain the same number of gas particles

Correct, only if the two containers are identical: since the two containers of the two different gases are at the same temperature and pressure, the equation pV = nRT, shows that if the volumes are equal the number of particles are the same.

David cannot assume option C, which states both containers contain the same number of gas particles since he only knows the temperature and pressure of both gases. Without knowledge of the volume, he cannot determine the number of particles via the Ideal Gas Law.

In this question, David does not have enough information to assume that C. both containers contain the same number of gas particles. This is because simply having the same temperature and pressure for two different gases does not confirm they have the same number of particles.

In the units of Ideal Gas Law, which states PV = nRT, 'P' stands for pressure, 'V' is volume, 'n' indicates number of moles i.e., the number of particles, 'R' is the universal gas constant, and 'T' is Temperature.

From this, we can see that the number of gas particles is proportional to the pressure and volume, and inversely proportional to the temperature. Therefore, without information about volume, we can not determine if both containers have the same number of particles.

The other possibilities regarding pressure, temperature, and volume changes are governed by the principles of gas laws, such as Boyle's, Charles', and Gay-Lussac's laws.

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Answer:

helium

Explanation:

coz it take part In fusion reaction

Nuclear fusion is the source of energy for stars. Besides hydrogen, helium element is most likely also common in stars.

Energy is the ability to perform work in physics. It might exist in several different forms, such as potential, kinetic, thermodynamic, electrical, chemical, radioactive, etc. Additionally, there is heat and work, which is energy being transferred through one body to the other.

Energy is the ability to perform work in physics. It might exist in several different forms, such as potential, kinetic, thermodynamic, electrical, chemical, radioactive, etc. Additionally, there is heat and work, which is energy being transferred through one body to the other. Nuclear fusion is the source of energy for stars. Besides hydrogen, helium element is most likely also common in stars.

Therefore,  besides hydrogen, helium element is most likely also common in stars.

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Answer:

An electrolyte is used in an alkaline zinc/manganese dioxide cell. There are two electrodes in the battery, one is positive (zinc) and the other is negative (manganese dioxide). Oxidation takes place at anode, while at cathode reduction reaction occurs.  

The half-reactions are:

Reaction at Anode:

Zn(s) + 2OH−(aq) → ZnO(s) + H2O(l) + 2e− (Oxidation)

Reaction at Cathode:

2MnO2(s) + H2O(l) + 2e− → Mn2O3(s) + 2OH−(aq) (Reduction)

Overall Reaction:

Zn(s) + 2MnO2(s) ⇌ ZnO(s) + Mn2O3(s)

Answer:

different

Explanation:

physical properties are the measure the melting point boiling point and freezing point and much more

Answer:

different

Explanation:

Take for example the colligative properties: freezing point depression and boiling point elevation. As their name indicates one measure the decrease of the freezing point and the other one the increment of the boiling point, of a solvent on the addition of a non-volatile solute. So, neither the physical properties of the solvent nor the solute is equal to the physical properties of the solution they made.

Answer: D. 75g

Explanation: The answer is 75 g because due to the law of the conservation of mass no mass can be lost. So if you are making that t=mixture the mass will be the three weights combined because you are combining those three things.

Due to lack of total mass information of the alloy, we cannot calculate the percentage of zinc directly. Instead, for a zinc-and-oxygen compound with a known mass, the percentage of zinc can be found by dividing the mass of zinc by the total mass of the compound and multiplying by 100, which in a given example, results in approximately 80.35% zinc by mass.

To calculate the percentage of zinc in the alloy, we need to know the total mass of the alloy. Since only the mass of pure zinc (66 g) is given and not the total mass of the alloy, we can't calculate the percentage directly. However, we can calculate the percentage composition of zinc in a compound using its mass before and after decomposition. In the given reference, a 20.00 g sample of a zinc-and-oxygen compound is decomposed and 16.07 g of zinc remains, which is used to determine the percent composition.

To calculate the percentage of zinc in the compound:

Divide the mass of zinc (16.07 g) by the total mass of the compound (20.00 g).

Multiply the result by 100 to get the percentage.

So the calculation will be (16.07 g \/ 20.00 g) \\times 100%, which gives about 80.35%. This means that by mass, the compound is mostly zinc.

Answer:

a) [H⁺] = 3.16 x 10⁻⁴ M.

b) pH = 3.5.

c) The solution is acidic.

Explanation:

a) Find [H⁺]

∵ [H⁺] [OH⁻] = 10⁻¹⁴.

∴ [H⁺] = 10⁻¹⁴/ [OH⁻] = 10⁻¹⁴/ (3.16 x 10⁻¹¹ M) = 3.16 x 10⁻⁴ M.

b) What is the pH?

∵ pH = - log[H⁺].

[H⁺] = 3.16 x 10⁻⁴ M.

∴ pH = - log(3.16 x 10⁻⁴ M) = 3.5.

c) Is the solution acidic, basic, or neutral?

pH is a scale from 0 to 14.

∵ pH = 3.5 < 7.

∴ The solution is acidic.

Answer:

D. Freezing

Explanation:

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Answer:

A. Melting

Explanation:

In the above question we noticed that there is a passage from a regular and well compacted carbon dioxide molecules to molecules in a less compact and lower density pattern after a period of heating. According to this description we can conclude that a physical process called "Melting" occurred, which is the process, where a solid substance (which has very compacted molecules) when heated becomes a liquid substance, with less compacted molecules and lower density.

Melting explains the changeover from heating to solid state to liquid state. Heating causes the temperature of the substance to rise to its melting point. The temperature does not rise while fusion is taking place, that is, only after all the substance has gone into liquid state does the temperature rise again.

The melting point of a substance is the temperature at which that substance changes from solid to liquid state.

Answer: Option (A) is the correct answer

Explanation:

When a solute completely dissolves a solvent with uniform composition then it results in a homogeneous mixture which is also known as a solution.

For example, coffee is brewed with water then coffee dissolves completely and uniformly into the water making a clear solution.

Whereas in a tomato juice particles remain suspended and it is called a suspension.

Ranch salad dressing is a heterogeneous mixture as particles are non-uniformly distributed.

Muddy water is also a suspension as particles settle at the bottom after some time.

Therefore, we can conclude that out of the given options brewed coffee is a solution.

Answer:

Explanation:

You can support your choice on basis of the collision theory.

According to the collision theory, the chemical reactions happen when the molecules collide with each other, in the correct orientation and with enough kinetic energy to overcome the activation energy.

As consequence, the larger the number of collisions the larger the rate of a reaction.

In the case of a reaction that involves gases, decreasing the volume, will increase the pressure and the concentration (volume is inversely related to both the pressure and the concentration) causing the molecules to be closer to each other and to collide with higher frequency, this is you will expect more collisions, and so an increase on the rate of the reaction. That is expressed by the last choice: decrease the volumen to increase pressure and to increase concentration.

Answer:

d

Explanation:

Answer:

The number of molecules in a mole (known as Avogadro's constant) is defined such that the mass of one mole of a substance, expressed in grams, is equal to the mean molecular mass of the substance. The molecular mass of CO2 = 12+2x16 = 44, so the mass of a mole of CO2 is approximalty 44 grams

Explanation:

Answer:

C. In every area of work.

Explanation:

(Apex)

In every area of work, chemicals are found. Hence, option C is correct.

A chemical is any substance that has a defined composition.

In every area of work, chemicals are found.

Some commonly used workplace chemical hazards include:

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Explanation:

Endothermic vs. Exothermic Reactions. An endothermic reaction occurs when energy is absorbed from the surroundings in the form of heat. Conversely, an exothermic reaction is one in which energy is released from the system into the surroundings. The terms are commonly used in the physical sciences and chemistry.

Final answer:

Endothermic reactions absorb energy, causing environmental temperature to decrease, like in photosynthesis, while exothermic reactions release energy, increasing environmental temperature, as seen in the combustion of substances like paper. Energy changes in these reactions are due to bond forming and breaking, with endothermic reactions needing energy input and exothermic reactions releasing energy.

Explanation:

Chemical reactions can broadly be classified into two types: endothermic and exothermic reactions. Endothermic reactions absorb energy from the surroundings, often in the form of heat, leading to a temperature decrease in the environment. A classic example of an endothermic reaction is photosynthesis in plants, where solar energy is absorbed to convert carbon dioxide and water into glucose and oxygen. On the other hand, exothermic reactions release energy, usually causing a temperature increase.

Combustion of substances, such as burning paper, is an exothermic reaction because it releases heat into the surroundings. The energy difference between the reactants and products is what drives these endothermic and exothermic processes, with the former having higher potential energy in the products and the latter having higher potential energy in the reactants.

When considering the energy change during a chemical reaction, it's the formation and breaking of chemical bonds that result in energy being absorbed or released. Endothermic reactions require energy to break bonds within the reactants, leading to a higher potential energy in the products compared to the reactants.

Conversely, exothermic reactions release energy when new bonds are formed in the product molecules, which possess less energy than the reactants. If we were to draw energy graphs for these reactions, an endothermic reaction graph would depict an upward curve from reactants to products, reflecting an input of energy, whereas an exothermic reaction graph would show a downward curve, indicating that energy is released.

Answer:

[tex]NO_2^-[/tex]

Explanation:

[tex]NO_2^- + H_2O\rightarrow HNO_2+OH^-[/tex]

A Bronsted acid is a substance which donates protons to another substance.

In this case, [tex]H_2O[/tex] is donating a proton to the nitrite ion.

Thus, it is the Bronsted acid in this equation.

Answer:

H₂O is the Bronsted Acid in this reaction.

Explanation:

A Brønsted-Lowry acid is any species capable of donating a proton (H+).

A Brönsted-Lowry base is a substance capable of gaining or accepting a proton (H+).

In this way, the acid-base reaction is one in which a transfer of protons from the acid to a base occurs.

This theory, unlike Arrhenius theory does not require the presence of water as a solvent, but includes any type of solvent.

The conjugate acid of the base, is the one that is formed when the base receives an H +

The conjugate base of the acid is the base formed when the acid yields an H +.

In this case, you have:

NO₂⁻ + H₂O → HNO₂ + OH⁻

Water acts as an acid yielding a proton to NO₂⁻, which in turn acts as a base and forms the HNO₃ conjugate base.

Answer:

Explanation:

Pressure is defined as force per unit area that a fluid exerts on its surroundings. Pressure, P, is a function of force, F, and area, A: P = F/A. The SI unit for pressure is the pascal (N/m2), but other common units of pressure include pounds per square inch (psi), atmospheres (atm), bars, inches of mercury

Pressure is measured by a device called a barometer and pressure gauge. Pressure measures the force exerted on the area of something.

Pressure is a force that is exerted on an area of the object or subject and is measured in a bar, pascal, psi, etc. It can be said that it measures the force applied by any gas or liquid on the surface area of the object.

It is important in fluid mechanics, animal anatomy and plant anatomy as the pressure is the driving force of the liquid and the gaseous component in the body system that is very essential for survival.

Therefore, pressure measures force per unit area.

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C. Heatstroke

heat stroke is the maximum critical heat-related illness. It occurs while the body can not control its temperature: the body's temperature rises rapidly, the sweating mechanism fails, and the body is not able to cool down.

Heatstroke is a condition caused by your body overheating, usually because of prolonged exposure to or physical exertion in high temperatures. This most critical shape of heat injury, heatstroke, can occur in case your body temperature rises to 104 F (40 C) or higher. The condition is most common in the summer season months

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Answer:

=14.8 grams

Explanation:

The remaining amount is normally calculated using the formula:

Remaining mass= 1/2ⁿ × Original mass where n is the number of half-lives.

Therefore, original mass= Remaining mass × 2ⁿ

Remaining mass= 2.2 grams

Number of half lives= 2.75 half lives

Original mass= 2.2g × 2²·⁷⁵

=14.8 grams

Answer:

meiosis II

Explanation:

Division of replicated chromosomes occurs during meiosis II.

Hope this helps,

The division of chromosomes occurs during the anaphase of mitosis and meiosis II.  

Cell division is a process of division of a parent cell into daughter cells. The daughter cells contain the characters of the parent cell and further splits up into more cells. There are two types of cell division, mitosis and meiosis.

In mitosis cell division, a parent cell divided into two daughter cells and this process helps in growth and development of the body. Another type of division is meiosis division where each parent cell splits up into four daughter cell and this type of cell division is observed in sexual reproduction.

Answer:

kintic

Explanation:

Answer:

The system's potential energy is increasing.

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