Read the given expression. X = number of protons − number of core electrons Which of the following explains the identity of X and its trends across a period? (5 points) a X is the effective nuclear charge, and it remains constant across a period. b X is the screening constant, and it remains constant across a period. c X is the effective nuclear charge, and it increases across a period. d X is the screening constant, and it increases across a period.

In a REDOX titration, one specie is oxidized while the other is reduced. The concentration of methanol is 0.012  mol L-1. Methanol is the oxidizing agent while permanganate is the reducing agent.

The average titre value is; \(\frac{7.95 + 7.10 + 7.00 + 7.10}{4}\) = 7.29 mL

Equation of the reaction is:

\(4MnO4- + 12H+ + 5CH3OH ----> 4Mn2+ + 11H2O + 5HCOOH\)

Concentration of oxidizing agent = CA = ?

Concentration of reducing agent = CB = 0.0021 mol L-1

Volume of oxidizing agent =  VA= 7.29 mL

Volume of reducing agent = VB = 50.00 mL

Number of moles of oxidizing agent NA = 4

Number of moles of reducing agent NB = 5

Note that NA and NB are obtained from the balanced reaction equation

CAVA/CBVB = NA/NB

CAVANB = CBVBNA

CA =  CBVBNA/VANB

CA = 0.0021 mol L-1 * 50.00 mL * 4/7.29 mL * 5

CA= 0.012  mol L-1

For a comprehensive definition of redox titration see

https://brainly.com/question/24018439

The 195 represent in the isotope notation represents the atomic mass.

Isotope notation is a way of representing atoms of a particular element that have the same number of protons but different numbers of neutrons. Isotopes are identified by their atomic mass, which is the sum of the number of protons and neutrons in the atom's nucleus.

In the isotope notation, the number that comes after the element's symbol represents the mass number of the isotope. In the case of 195Pt, "195" represents the mass number of the isotope, which is the sum of the number of protons and neutrons in the nucleus of the atom.

Learn about isotope notation here https://brainly.com/question/1878687

#SPJ1

Answer:

Solution temperature.

Explanation:

Hello there!

In this case, considering this question about chemical kinetics, it will be possible for us to analyze two perspectives:

1. Molecular: here, we infer that the solution temperature will provide more energy to the molecules in order to undergo more effective crashes which will make more products and therefore, increase the rate constant.

2. Mathematical: by means of the Arrhenius equation, it will be possible to tell that the increase in the temperature of the system, the negative of the exponent present in such equation will increase and therefore turn the rate constant bigger.

In such way, we infer the answer is solution temperature.

Regards!

pH of the Sr(OH)₂ solution : 12.6

pH is the degree of acidity of a solution that depends on the concentration of H⁺ ions. The greater the value the more acidic the solution and the smaller the pH.  

pH = - log [H⁺]  

Sr (OH) ₂ solution is a base with valence 2, so we determine the pOH from the OH ion concentration - which is expressed by pOH = - log [OH -]. After that we determine the pH value from the relationship:

[H⁺] [OH⁻] = Kw=10⁻¹⁴

pH + pOH = 14

Sr(OH)₂⇒Sr²⁺+2OH⁻

From equation [Sr(OH)₂] : [OH⁻]=1 : 2, so [OH⁻]=

\(\tt [OH^-]=2\times 2.10^{-2}=4.10^{-2}~M\)

\(\tt pOH=-log[OH^-]\\\\pOH=-log~4.10^{-2}\\\\pOH=2-log~4\rightarrow 1.398 \\\\pH+pOH=14\\\\pH=14-1.398\\\\pH=12.6\)

pH is the measurement of the concentration of hydrogen or hydronium ion in an aqueous solution. The pH of strontium hydroxide is 12.6.

The pH is the potential of hydrogen or the negative log of its concentration.

First, calculate the pOH of strontium hydroxide by:

\(\begin{aligned} \rm pOH &= \rm - log [OH ^{-}]\\\\&= \rm -log [4\times10^{-2}]\\\\&= 1.398\end{aligned}\)

Now, calculate pH from pOH as:

\(\begin{aligned}\rm pH &= 14 - \rm pOH\\\\&= 14 - 1.398\\\\&= 12.6\end{aligned}\)

Therefore, 12.6 is the pH of strontium hydroxide.

Learn more about pH here:

https://brainly.com/question/10725749

There are many factors that we can take into account when attempting to relate microscopic bonding properties to solid-state properties, for example, the rigid and immobile nature of solid states and their molecular bonds.

Solid-state properties are simply put, the properties we can observe and measure when studying an element in solid form. These solids have specific characteristics such as:

and so on, which although not initially obvious, are caused by the microscopic molecular bonds of their atoms.

The microscopic properties of solids are very similar to that of the solid-state properties. The atoms of a solid are very close together and strongly bonded to one another, because of this the atoms form a very rigid structure that resists changes to their shape or volume, much like the macroscopic properties of the solid. This serves to show how these properties may cause the solid-state effects we can observe normally.  

To learn more visit:

https://brainly.com/question/4833954?referrer=searchResults

Answer:

0.209M

Explanation:

M1V1=M2V2

(28.5 mL)(0.183M)=(25.0mL)(M)

M2= 0.209M

*Text me at 561-400-5105 for private tutoring if interested: I can do homework, labs, and other assignments :)

The speed that reflects the average kinetic energy of the molecules is known as the root-mean-square speed. using N2 at 25 °C.

The square root of temperature and the square root of the molar mass are both exactly proportional to the rms velocity. Thus, doubling the rms velocity of the molecules when the temperature of a specific gas is quadrupled.

The root mean square velocity of gaseous hydrogen molecules equals that of oxygen molecules at 47°C at what temperature.

A gas will effuse more quickly the lighter it is; conversely, the heavier a gas is ,the slower it flows, the more. Helium (He) will have the highest rate of effusion since it has the lowest molecular weight (atomic weight, in this example).

To know more about mean-squared speed visit:-

https://brainly.com/question/28747486

#SPJ1

Answer:

Answer:

The concentration is 2.277

Explanation:

The formula for finding the concentration of a solution is C= mole of solute divided by the volume of the solution

Therefore, C= 2.05/0.900

C=2.277

Answer:2.9 grams

Explanation:i had this question

Answer:

that is a solid and that there are other ways to make a fire?

Sometimes a neutral oxygen atoms gains electrons. The oxygen then becomes an anion with a negative charge.

All the atoms undergoes chemical reactions to attain the octet electronic configuration. It means that it tries to attain the configuration of noble gases, which has the most stable atoms.

Oxygen has 6 electrons in its outer shell. It accepts two more electrons to attain the configuration of neon. As it attains electrons the atoms become negatively charged ions, called anions. It will now become O²⁻.

So the oxygen atom attains electrons to become an anion, with negative charge.

For more information regarding anions, kindly refer

https://brainly.com/question/20781422

#SPJ4

Answer:

4.74

Explanation:

pH= -log[H+]

pH= -log(1.8 x 10^-5)= 4.74

This technique has been used to identify the presence of gases such as oxygen, methane, and carbon dioxide in the atmospheres of exoplanets.  

i) To estimate the frequency of the violet (leftmost) emission, we can use the equation v = c/λ, where v is frequency, c is the speed of light (3.00 x 10^8 m/s), and λ is the wavelength of the emission in meters. The wavelength of the violet emission is 400 nm or 400 x 10^-9 m, so the frequency can be calculated as v = (3.00 x 10^8 m/s) / (400 x 10^-9 m) = 7.50 x 10^14 Hz.

ii) To estimate the energy of the violet emission, we can use the equation E = hv, where E is energy, h is Planck's constant (6.63 x 10^-34 Js), and v is frequency in Hz. Substituting the frequency calculated in part (i), we get E = (6.63 x 10^-34 Js) x (7.50 x 10^14 Hz) = 4.97 x 10^-19 J.

b. The spectral lines are produced by the electrons within the atoms of this element, which can absorb or emit specific amounts of energy to move between different energy levels. These energy transitions result in the emission or absorption of photons with specific wavelengths and frequencies, giving rise to the observed emission spectrum.

c. The violet emission line represents the photon with the most energy since it has the shortest wavelength (400 nm) and highest frequency (7.50 x 10^14 Hz) among the lines shown. This highest energy does not necessarily represent the energy of the valence electrons, but rather corresponds to the specific energy transitions occurring within the atoms of the element.

d. Emission spectra can be used to determine the gases present in the atmosphere of a far-away planet by analyzing the specific wavelengths of the emitted or absorbed light from the planet. Each gas has a unique emission or absorption spectrum, allowing scientists to identify the gases present in the planet's atmosphere.

To know more about Wavelength , visit :

https://brainly.com/question/13533093

#SPJ1

Answer:

conservation of mass

Answer:

The answer is C. After it has hit the ground.

Explanation:

The ball would have the least kinetic energy when it has already hit the ground. The ball is no longer in motion once it's hit the ground. Kinetic energy is when the particles of an object are in motion. Therefore, kinetic energy is at its lowest when an object is not in motion.

Here is a lab I recommend using to answer questions similar to this one:

https://phet.colorado.edu/sims/html/energy-skate-park/latest/energy-skate-park_en.html

(I know this is a bit of a late answer, but I hope it still helps!)

Answer:

Explanation:

This is an acid-base reaction (neutralization): CaCO3 is a base, HCl is an acid.

Given chemical equation: CaCO3 + HCl → CaCl2 + H2O + CO2

Balanced chemical equation: CaCO3 + 2HCl → CaCl2 + H2O + CO2

Answer:

Endothermic.

Explanation:

Hello there!

In this case, it is necessary to keep in mind that exothermic processes are characterized by the release of energy and the endothermic processes by the absorption of heat. In such a way, every process from solid to liquid or gas is endothermic as they require energy to separate the molecules and therefore turn out in the phase change. On the other hand, every process from gas to liquid or solid is exothermic as heat is released to rejoin the molecules and produce the phase change.

Therefore, since solid water molecules tend to be well-arranged, it is necessary to add heat to the system to produce the phase change until gas; in such a way, this process is endothermic as energy must be absorbed by the ice.

Best regards!

Answer:

We do something called hypothesis

Answer:

1. Make an observation.

2. Ask a question.

3. Propose a hypothesis.

4. Make predictions.

5. Test the predictions.

6. Iterate.

and if it can't be trsted the you did something wrong

Explanation:

The scientific method

At the core of biology and other sciences lies a problem-solving approach called the scientific method. The scientific method has five basic steps, plus one feedback step:

Make an observation.

Ask a question.

Form a hypothesis, or testable explanation.

Make a prediction based on the hypothesis.

Test the prediction.

Iterate: use the results to make new hypotheses or predictions.

The scientific method is used in all sciences—including chemistry, physics, geology, and psychology. The scientists in these fields ask different questions and perform different tests. However, they use the same core approach to find answers that are logical and supported by evidence.

Scientific method example: Failure to toast

Let's build some intuition for the scientific method by applying its steps to a practical problem from everyday life.

Answer:

spinning

Explanation:

Answer:

\(m_{AgNO_3}=577.6mg\)

Explanation:

Hello there!

In this case, according to the given chemical reaction, it is first necessary to compute the moles of reacting LiOH given its molar mass:

\(n_{LiOH}=81.5mg*\frac{1g}{1000mg}*\frac{1mol}{23.95g} =0.0034molLiOH\)

Thus, since there is a 1:1 mole ratio between lithium hydroxide and silver nitrate (169.87 g/mol) the resulting milligrams turn out to be:

\(m_{ AgNO_3}=0.0034molLiOH*\frac{1molAgNO_3}{1molLiOH} *\frac{169.87gAgNO_3}{1molAgNO_3} *\frac{1000gAgNO_3}{1gAgNO_3} \\\\m_{AgNO_3}=577.6mg\)

Best regards!

Answer:

AgNO3+Li-->LiNO3+Ag

It is already balanced.

And turns out to be M AgNO3=577.6mg

Hope this helps!

The flammability of natural gas ranges from 5 to 15 percent. This indicates that no combustion would take place in any mixture with a natural gas to air ratio of less than 5% or greater than 15%.

The lowest concentration of a gas at which combustion can occur is known as the LEL. A reading in%LEL measures the percentage of that LEL value. The LEL, for instance, is 5% by volume for methane. Half of that amount, or 2.5% by volume, is 50% LEL.

Divide the unknown concentration by the LEL specified in the NFPA Handbook to determine the LEL of any gas in air.

To know more about flammability visit:-

brainly.com/question/13323225

#SPJ1

Solubility is the amount of a substance that can be dissolved in a liquid to form a solution.

One fluid's (liquid or gas) solubility in another can be entire (e.g., methanol and water are completely miscible) or partial.

A material's solubility in two solvents is measured by the distribution coefficient, which is used in some separation techniques (such as absorption and extraction).

In general, as temperature rises, so do the solubilities of solids in liquids, while they fall as temperature rises and rise with pressure for gases.

Thus, Solubility is the amount of a substance that can be dissolved in a liquid to form a solution.

Learn more about Solubility, refer to the link:

https://brainly.com/question/29661360

#SPJ1

Answer:

By reacting carbon monoxide and hydrogen the formation of methanol takes place, the reaction is,

CO(g)+2H₂(g)⇔CH₃OH (g)

Based on the given reaction, one mole of methanol is obtained by reacting one mole of carbon monoxide (CO) with the two moles of hydrogen (H₂). It is mentioned in the question that for the reaction 500 mol of carbon monoxide and 750 moles of hydrogen are present.

Therefore for 500 moles of carbon monoxide, there is a requirement of 2 × 500 moles of hydrogen, which is equivalent to 1000 moles of hydrogen (H₂). However, only 750 moles of hydrogen is present. Therefore, the limiting reactant in the given case is H₂. The present moles of H₂ will react with 0.5 × 750 moles of CO = 375 mole of CO

The additional or excess concentration of CO, which is the excess reactant will be, 500-375 = 125 moles.

Answer:

1000 mL.

Explanation:

From the question given above, the following data were obtained:

Volume of stock solution (V1) = 40 mL

Molarity of stock solution (M1) = 1.25 M

Molarity of diluted solution (M2) = 0.05 M

Volume of diluted solution (V2) =...?

The volume of diluted solution can be obtained as shown below:

M1V1 = M1V1

1.25 × 40 = 0.05 × V2

50 = 0.05 × V2

Divide both side by 0.05

V2 = 50/0.05

V2 = 1000 mL

Therefore, the stock solution must be diluted to 1000 mL to obtain a 0.05 M solution of NaCl.

Answer:

OH⁻ is the Bronsted-Lowry base.

Explanation:

A Bronsted-Lowry base is a substance that accepts protons. In the chemical equation, OH⁻ accepts a proton from H₂PO₄⁻ to become H₂O. H₂PO₄⁻ would be a Bronsted-Lowry acid because it donates a proton to OH⁻ and becomes HPO₄²⁻.

Hope that helps.

The chemical formula for the molecule you provided is C2H5Cl.

In the molecule, the central atom is carbon (C), which is bonded to two hydrogen atoms (H) and one chlorine atom (Cl). The carbon atom forms single bonds with each of the hydrogen and chlorine atoms, resulting in a linear structure.

To write the chemical formula, we start by indicating the number of atoms of each element present in the molecule. In this case, there are two carbon atoms (C2), five hydrogen atoms (H5), and one chlorine atom (Cl1).

Next, we write the symbols for the elements in the order of their appearance. The formula is typically written with the carbon atom first, followed by hydrogen, and then any other elements in alphabetical order. Therefore, the chemical formula for the molecule is C2H5Cl.

The subscripts in the formula indicate the number of atoms of each element in the molecule. In this case, there are two carbon atoms, five hydrogen atoms, and one chlorine atom.

It's important to note that the formula represents the simplest ratio of atoms in the molecule. It does not provide information about the spatial arrangement or bonding pattern of the atoms. Additional structural information, such as the arrangement of atoms in space, would require a more detailed representation, such as a Lewis structure or a three-dimensional model.

for more questions on chemical formula

https://brainly.com/question/21393201

#SPJ8

Answer:

Here is your answer!!

Explanation:

YW! :]