Which of the following is the trend down a period?
A. The number of complete electron shells increases by one.
B. The number of complete electron shells stays the same.
C. The number of outer shell electrons decreases by one.
D. None of these.

Answers

Answer 1

Answer:

B. The number of complete electron shells stays the same.

Explanation:

The periods on a periodic table consists of those elements that are arranged in the horizontal row in the periodic table.

Elements in the same period have the same number of electron shells and this corresponds to the period. This implies that elements of period 2 have two electron shells, those of period 3 have three shells and so on.

The number of Valence electrons of the elements on the same period increases progressively by one across the period from left to right.

A group is the vertical column to which elements are arranged on the periodic table. Elements in the same group have the same number of Valence electrons and the number of shell increases down a group.

When we go down a period, the number of shell stays the same.


Related Questions

What volume of 5.00 × 10-3 m hno3 is needed to titrate 80.00 ml of 5.00 × 10-3 m ca(oh)2 to the equivalence point? what volume of 5.00 × 10-3 m hno3 is needed to titrate 80.00 ml of 5.00 × 10-3 m ca(oh)2 to the equivalence point? 80.0 ml 160. ml 10.0 ml 40.0 ml?

Answers

Answer:

= 160 mL

Explanation:

The equation for the reaction is;

Ca(OH)2 + 2HNO3 -----> Ca(NO3)2 + 2H2O

Moles of Ca(OH)2 =  0.080 L x 5.00^-3 M

                              = 0.0004 moles

From the reaction; 2 moles of HNO3 reacts with 1 mole of Ca(OH)2

Thus; moles of HNO3 = 0.0004 Moles × 2

                                    = 0.0008 moles

Volume = moles/ molarity

Therefore; volume of HNO3= 0.0008 Moles/ 5 × 10^-3 M

                                              = 0.16 L or 160 mL

The volume of 5×10⁻³ M HNO₃ needed to titrate 80ml of 5×10⁻³ M ca(oh)2 to the equivalence point is 160mL.

How we calculate volume from moles?

Volume of any solution will be calculated by using moles and molarity as:

Volume = moles / molarity

Given chemical reaction is:

Ca(OH)₂ + 2HNO₃ → Ca(NO₃)₂ + 2H₂O

From the stoichiometry of the reaction it is clear that,

2 mole of HNO₃ = react with 1 mole of Ca(OH)₂

Given volume of Ca(OH)₂ = 80mL = 0.080L

Given molarity of Ca(OH)₂₂ = 5×10⁻³ M

Moles of Ca(OH)₂ = 0.080L x 5×10⁻³M = 0.0004 moles

0.0004 moles of Ca(OH)₂ = react with 2×0.0004 = 0.0008 moles of HNO₃

Given molarity of HNO₃ = 5×10⁻³ M

Volume of HNO₃ = 0.0008moles / 5×10⁻³ M = 0.16L = 160mL

Hence, 160mL of HNO₃ is required.

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According to periodic trend, which of the following most likely has the highest ionization energy? Be B Ne O

Answers

Answer:

Ne

Explanation:

Answer: The correct answer is Beryllium.

Explanation:

Ionization energy is defined as the energy required to remove valence electron from an isolated gaseous atom. It is expressed as [tex]E_i[/tex]

[tex]X(g)\rightarrow X^{n+}(g)+ne^-[/tex]

Energy required for a stable molecule (having fully filled and half filled electronic configuration)

The electronic configuration for the elements given are:

1. Be : [tex]1s^22s^2[/tex]

This element will have the highest ionization energy because this element has stable electronic configuration and electrons present in '2s' orbital is near to the nucleus. So, to remove this electron, we need a huge amount of energy.

2. B : [tex]1s^22s^22p^1[/tex]

This element does not have stable electronic configuration. So, this will not have highest ionization energy.

3. Ne : [tex]1s^22s^22p^6[/tex]

As, this element has stable electronic configuration but the valence electron is far from the nucleus and does not require a huge amount of energy to remove it. So, this will not have highest ionization energy.

4. O : [tex]1s^22s^22p^4[/tex]

This element does not have stable electronic configuration. So, this will not have highest ionization energy.

From the above information, we can conclude that the Beryllium has the highest ionization energy.

List your example of turning an observation into a hypothesis. Be sure to list all five steps: observation, explanation, test (independent variable), prediction (dependent variable), and hypothesis

Answers

A simple hypothesis is a prediction of the relationship between two variables: the independent variable and the dependent variable.

Drinking sugary drinks daily leads to obesity.

A complex hypothesis examines the relationship between two or more independent variables and two or more dependent variables.

Overweight adults who 1) value longevity and 2) seek happiness are more likely than other adults to 1) lose their excess weight and 2) feel a more regular sense of joy.

A null hypothesis (H0) exists when a researcher believes there is no relationship between the two variables, or there is a lack of information to state a scientific hypothesis. This is something to attempt to disprove or discredit.

There is no significant change in my health during the times when I drink green tea only or root beer only.

This is where the alternative hypothesis (H1) enters the scene. In an attempt to disprove a null hypothesis, researchers will seek to discover an alternative hypothesis.

My health improves during the times when I drink green tea only, as opposed to root beer only.

A logical hypothesis is a proposed explanation possessing limited evidence. Generally, you want to turn a logical hypothesis into an empirical hypothesis, putting your theories or postulations to the test.

Cacti experience more successful growth rates than tulips on Mars. (Until we're able to test plant growth in Mars' ground for an extended period of time, the evidence for this claim will be limited and the hypothesis will only remain logical.)

An empirical hypothesis, or working hypothesis, comes to life when a theory is being put to the test, using observation and experiment. It's no longer just an idea or notion. It's actually going through some trial and error, and perhaps changing around those independent variables.

Roses watered with liquid Vitamin B grow faster than roses watered with liquid Vitamin E. (Here, trial and error is leading to a series of findings.)

A statistical hypothesis is an examination of a portion of a population.

If you wanted to conduct a study on the life expectancy of Savannians, you would want to examine every single resident of Savannah. This is not practical. Therefore, you would conduct your research using a statistical hypothesis, or a sample of the Savannian population.

Final answer:

Turning an observation into a hypothesis involves observing a natural event, formulating a plausible explanation, testing this explanation by manipulating an independent variable, predicting the outcome on a dependent variable, and stating a hypothesis that brings all these elements together.

Explanation:

Turning an observation into a hypothesis involves several critical steps, each building upon the previous to develop a testable prediction about a natural phenomenon. Below is an example detailing this process.

Observation: Plants in a garden receiving more sunlight tend to be more vibrant and grow taller than those in shaded areas.

Explanation: Sunlight may provide energy that is essential for the growth and health of plants.

Test (Independent Variable): The amount of sunlight exposure plants receive.

Prediction (Dependent Variable): The health and growth rate of the plants.

Hypothesis: If plants are exposed to more sunlight, then they will grow taller and have a more vibrant appearance, because sunlight provides the necessary energy for photosynthesis.

This hypothesis can then be tested through experimentation, ultimately contributing to the cycle of scientific inquiry.

What inorganic molecule is carbon normally found in?

Answers

It’s CO2

Carbon dioxide

A titration involves adding a reactant of known quantity to a solution of an another reactant while monitoring the equilibrium concentrations. this allows one to determine the concentration of the second reactant. the equation for the reaction of a generic weak acid ha with a strong base is ha(aq)+oh−(aq)→a−(aq)+h2o(l)

Answers

A titration is a precision technique utilized in chemistry to identify the concentration of an unknown solution by neutralizing it with a reactant of known concentration, using an indicator or pH meter to detect the endpoint.

A titration is a quantitative chemical analysis method used to determine the concentration of an unknown solution. During a titration, a reactant solution of known concentration is added to a sample containing the analyte. The volume required to completely neutralize the analyte is measured, indicating the endpoint of the titration.

In the case of an acid-base reaction, when the weak acid HA reacts with the strong base OH⁻, the products formed are A− and water (H₂O).

An indicator or pH meter is employed to detect the point at which equivalent amounts of acid and base have reacted, signifying that the reaction has reached neutrality. This stoichiometric point allows the concentration of the second reactant to be calculated.

The atomic number of a nuclide that undergoes alpha decay _____.

increases by 2
increases by 4
decreases by 2
decreases by 4

Answers

C. decreases by 2

The mass number decreases by 4, and the atomic number decreases by 2

Final answer:

The atomic number of a nuclide decreases by 2 during alpha decay due to the emission of an alpha particle, which consists of two protons and two neutrons.

Explanation:

The atomic number of a nuclide that undergoes alpha decay decreases by 2. Alpha decay is a nuclear reaction where an unstable atom emits an alpha particle, which consists of two protons and two neutrons (the same as a helium-4 nucleus). Because two protons are lost, the atomic number decreases by two.

At the same time, because a total of four nucleons (two protons and two neutrons) are lost, the mass number of the atom decreases by four.

Estimate the optimal number of neutrons for a nucleus containing 70 protons.

Answers

Atomic number 70

weight 173

number of neutron = weight - Atomic number

= 173 -70

=103

The optimal number of neutrons for a nucleus containing 70 protons is 130

Further explanation

In chemistry, the nucleus is the positively charged center of the atom that consist of protons and neutrons. It's also known as the "atomic nucleus"

The neutron is a subatomic particle with no net electric charge and a mass slightly greater than that of a proton. The neutron is have symbol n or n⁰. Protons and neutrons constitute the nuclei of atoms.

Neutron is a type of atomic particle which does not possess any kind of charge on it. It has neutral behavior toward atoms since it does not possess any kind of charges but it contributes to the mass of the atoms.

Atomic number = 70

Atomic weight = 173

Atomic weight = number of protons + number of neutrons

Atomic number = number of protons

Therefore, the number of protons = 70

Number of neutrons = atomic weight - number of protons

Number of neutrons = 173 - 70 = 103

Optimal number of neutrons = 130

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Answer details

Grade:  9

Subject:  chemistry

Chapter:  the optimal number of neutrons

Keywords: protons, nucleus, neutrons

Air resistance depends upon _____.

A. the inertia of a moving object

B. the velocity of a moving object

C. the mass of a moving object

D. the weight of a moving object


Answers

Answer:

ye its b

Explanation:

Final answer:

Air resistance highly depends on the velocity of a moving object. It also depends on other factors like the object's shape, size, and the fluid's density. Among the given options, velocity is the most accurate answer.

Explanation:

Air resistance, often termed as drag in physics, is the force that opposes an object's motion through a fluid (either gas or liquid). The statement 'Air resistance depends upon _____.' pertains to the factors affecting the magnitude of air resistance that an object experiences. Most accurately, air resistance depends on the velocity of a moving object (Option B). This relationship is particularly evident in larger velocities, where the air resistance can increase exponentially.

Additionally, air resistance is also affected by factors such as the shape and size of the object, and the density of the fluid (air in this case). For example, a smoothly shaped, small object experiences less air resistance compared to a larger or irregularly shaped object at the same velocity.

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Which of the following pieces of glassware can be used to measure the volume of a liquid with the
greatest accuracy?
a. Test tube
b. Beaker
c. Flask
d. Graduated cylinder

Answers

Answer:

The correct option is GRADUATED CYLINDER.

Explanation:

Each of the glassware used in the laboratory has its specific functions. The graduated cylinder is especially manufacture to facilitate the measurement of accurate volume of liquids in the laboratory. Measurements obtained by means of graduated cylinder can be considered to be moderately accurate; volumentric flasks are more accurate than graduated cylinder and should be used when higher precision are required.

Final answer:

The most accurate piece of glassware to measure the volume of a liquid is a graduated cylinder, due to its precise measurement markings. Other forms of glassware like test tubes, beakers, and flasks can also measure volume, but with less accuracy.

Explanation:

The piece of glassware used to measure the volume of a liquid with the greatest accuracy among the given options is a graduated cylinder. Test tubes, beakers, and flasks provide approximate measurements, but for higher accuracy, a graduated cylinder is used. This is due to the precise measurements inscribed on the surface of the cylinder. Graduated cylinders are typically used in scientific experiments where accuracy is crucial for obtaining reliable and valid results.

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What does the prefix cis- mean in chemistry

Answers

Answer:

this

Explanation:

a prefix meaning “with,” “together,” “in association,” and (with intensive force) “completely,” occurring in loanwords from Latin ( commit ): used in the formation of compound words before b, p, m: combine; compare; commingle.

Final answer:

In chemistry, the 'cis-' prefix indicates that two substituents are positioned on the same side of a double bond or ring structure, significantly impacting the compound's properties, as seen with cis-platin in cancer treatment.

Explanation:

In chemistry, the prefix cis- refers to molecules where two substituents are on the same side of a double bond or a ring structure. Cis/trans isomerism is an important concept where the arrangement of atoms can greatly affect the physical and biological properties of a compound. For instance, in cycloalkanes, a cis configuration has both groups oriented in the same direction, which is different from the trans configuration where groups are on opposite sides. An example of this significance in biology is the drug cis-platin, which is used in the treatment of ovarian and testicular cancers due to its ability to bind to DNA and inhibit replication.

Additionally, cis/trans isomerism can also be referred to as Z/E isomerism based on Cahn, Ingold, and Prelog's priority rules. While both cis and trans compounds share similar qualities, their different spatial arrangements result in distinct characteristics.

A mixture of two gases was allowed to effuse from a container. one of the gases escaped from the container 1.43 times as fast as the other one. the two gases could have been:

Answers

Answer:

C. Cl2 and SF6

Explanation:

According to the Graham's law of diffusion the rate of effusion or diffusion of a fixed mass of a gas is inversely proportional to the square root of its density or mass.For two gases; R1/R2 = √mm2/√mm1 ; where R1 and R2 are the rates of diffusion of the two gases  respectively, while mm1 and mm2 are the molecular masses respectively.

Therefore, in this case we need two gases that have a ratio of their rates of diffusion as 1.43.

Thus; For Cl2 and SF6

Molecular mass of Cl2 is 70.906 g/mol, while that of SF6 is 146.06 g/mol

Therefore, the ratio of their rates of diffusion will be;

√(MM of SF6)/√(MM of Cl2) = √ 146.06/√70.906

                                              = 1.4352

                                              = 1.43

Therefore; the two gases required are Cl2 and SF6

Final answer:

Based on Graham's law, if one gas effuses 1.43 times as fast as another, the faster-moving gas likely has a lower molar mass. An exemplary pair could be helium and neon.

Explanation:

The phenomenon of effusion is dictated by Graham's law, which states the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. If one of the gases escapes 1.43 times as fast as the other, it could be inferred that the slower-moving gas has a greater molar mass in comparison to the faster one due to an inverse relationship.

However, without specific details about the exact molar masses, it's challenging to state precisely what the gases could be. Nonetheless, in a hypothetical scenario, it could be a pair of helium and neon, where helium being lighter would effuse faster. Please remember, that this is just an illustrative example.

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What type of functional group is represented in the compound?
The indicated group is a NH group bonded to a central atom by a single bond.

Amine

Alkene

Inorganic compound

Alkyne

Answers

Answer:

Amine

Explanation:

This functional group is that of amines. Specifically a secondary amine. It is called an N-subsituted amino group.

Here, two Hydrogen atoms of ammonia have been replaced by alkyl and/or aryl groups. The functional group of this class of amines is -NHR (N-alkylamino or N-arylamino group).

The amines shows considerable basicity.

Answer:

amine

Explanation:

What are the answers to these questions and why?

Answers

Answer:

Explanation:

Here are the ones I'm certain of.

10, Transfer of electrons occurs in NaCl. That's another way of saying that the bond is ionic.

12. What is a polar molecule. The two hydrogens are + and the Oxygen is minus.

9. Contains just one sigma bond. H2 is made up of only 1 bond type. I'd pick this, but It's not certain.

=============

The one I'm uncertain of is 11. I'd pick E but it is a pure guess. The only other  choice is CO2 but I don't think CO2 is that way. You'll have to enter the answers to find out which is which.

Which of the following molecules has only single bonds?
a. CH2CH2
b. CH3CH3
c. CO2
d. CHCH

Answers

Answer:

C

Explanation:

it only bonded with one other molecule carbon/ oxgen=carbon dioxide

b. CH3CH3(Ethane) is the only molecule in the following that has only single bonds.

What are chemical bonds?

Chemical bonds are defined as the connection between two atoms or the strong force of attraction that is binding the two atoms which are the result of sharing of electrons.

There are many types of bonds namely: covalent bonds, hydrogen bonds, ionic bonds, metallic bonds, etcThe bond between 2 carbon atoms is always a covalent bond meaning sharing of electrons.A covalent bond can be either a single bond, double bond or triple bond. The structure of ethane only has a single bond.

Hence option a. is the right option.

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___________ is a comfortable number of guests for an evening of good conversation.

Ten or less
Ten to twelve
Thirteen to fifteen

Answers

Answer: 10 or less

Explanation: The reason it should be ten or less is because having to many people can make you feel uncomfortable. So you want to stick with a big group but not that big of a group.

Answer:

Ten or less is a comfortable number of guests for an evening of good conversation.  

Explanation:

Usually people visit their neighbors or go as guest to their relative houses during evening time. It is because evening is the exact time during which all the members of the family will be present at home. Some people like to converse with each other.  

The best count for comfortable evening conversation may be ten or less. It is considered as best because; if a guest is visiting our house we need to provide hospitality to them by serving something to eat and to provide space to sit. If the count goes above 10, it will become crowded and will cause problem in hospitality and will not pave wave for good conversation.

In an experiment to determine the acceleration due to gravity, one student holds a pencil at arm’s length and drops it. Another student starts a timer when the first student lets go and stops the timer when the pencil hits the ground. They repeat this several times and take an average. Is this a valid experiment, why or why not?

A. No, it is not valid because they are only dropping one item.
B. No, it is not valid because taking the average will increase rounding error.
C. Yes it is valid.
D. No, it is not valid because the short distance means there will be a lot of error due to the student’s reaction time.

Answers

I think it is not a valid experiment . I go with D

Final answer:

The experiment to determine acceleration due to gravity has potential flaws due to short drop distance and potential inconsistencies with timing due to human reaction times. A more accurate experiment would require a longer drop distance and more consistent timing method.

Explanation:

The experiment described for determining the acceleration due to gravity isn't completely invalid but it is overly simplified and prone to errors. Option D is the most accurate answer - the short drop distance and potential inconsistency with the start and stop times due to human reaction could induce significant errors into the measurements. A more precise experiment would include a longer drop distance, a more consistent timing method (for example, using sensor-based stopwatch triggers), and repeated tests with different objects to make sure the results are not specific to just the pencil.

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If the concentration of H+ is 1 x 10 ^-3 M, what is the pH? Is the solution acidic, neutral or basic? Be sure to include the formula and show your work for each step in the calculation.

Answers

Answer:

[tex]\boxed{\text{3; acidic}}[/tex]

Explanation:

[H⁺] = 1 x 10⁻³ mol/L

To get the pH, you take the negative logarithm of the hydrogen ion concentration.  

pH = -log[H⁺]

= -log(1 × 10⁻³)

= -log1 - log(10⁻³)

= 0 – (-3)

= 0 + 3

= 3

The pH is less than 7, so the solution is acidic.

According to pH values, the value below 7 indicates acidity. As per the given concentration of hydrogen ion, the pH value is 3 which means it is acidic.

What is the use of pH?

pH is the value to determine whether the solution is acidic or basic.

It can be calculated as

[tex]pH= -log[H^{+} ][/tex]

Given,

[H⁺] = 1 x 10⁻³ mol/L

[H⁺]= -log(1 × 10⁻³)

[H⁺]= -log1 - log(10⁻³)

[H⁺]= 0 – (-3)

[H⁺]= 0 + 3

[H⁺]= 3

Thus, it can be concluded that the pH value here is 3, it means it is acidic.

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Identify the missing numbers for Vanadium (V) for "A, ""B," and "C" in the chart below. The first number in the answer selection represents "A", the second number in the answer selection represents "B," and the third number in the answer selection represents "C."

Answers

Answer:

The right choice is:

B. 21, 21, 53.

Explanation:

Atomic Number = Number of electrons = Number of protons

So, the No. of protons (A) =  Number of electrons =21

Atomic Number (B) = Number  of electrons =21

Mass number (C) = Number of electrons + Number of neutrons = 21 + 32 = 53

So, the right choice is:

B. 21, 21, 53.

How would you find out if the enthalpy for the two questions exothermic or endothermic?

Answers

Answer:

Explanation:

The second one is quite simple. CH4 (methane) is the main component for natural gas. It is used to heat houses in many many areas. It it heats a house, it must give off heat. It is exothermic.

The first one is much less common and hard to reason. I think it is easier to see the reverse reaction

O2 ===> 2O

O2 is a fairly stable molecule. It takes energy to break the molecules apart. That makes this reaction endothermic.

So the reaction you are given is just the opposite. It must be exothermic.

2O ===> O2 must be exothermic.

What is emitted during gamma emission?

Electrons

Light

Alpha particles

Beta particles

Answers

Answer

Light

Explanation:

The gamma emission is an electromagnetic radiation, this kind of radiation come from the light.  

In gamma ray emission, a gamma ray is photon of light. Given that light does not have mass or charge, the symbol we use to identify it is: 00γ. With two zeroes.

Answer:

electromagnetic radiation

Explanation:

Will give brainliest!!Given the following balanced equation: 2K + Br2 —-> 2KBr
A. List each element on the reactant side and each element on the product side and assign the correct oxidation number to each.
B. Identify which element is oxidized in the reaction and which is reduced.
C. Identify the oxidizing agent in this reaction.

Answers

A. Reactant side: K(+1), Br2(0); Product side: K(+1), Br(-1). B. Potassium is oxidized, and bromine is reduced. C. Bromine is the oxidizing agent in this reaction.

A. Let's analyze the oxidation numbers for each element in the given equation:

On the reactant side:

- Potassium (K) has an oxidation number of 0.

- Bromine (Br2) is a diatomic molecule, and its oxidation number is 0.

On the product side:

- Potassium bromide (KBr) has potassium with an oxidation number of +1, and bromine with an oxidation number of -1.

B. To determine which element is oxidized and which is reduced, compare the oxidation numbers:

- Potassium goes from an oxidation number of 0 to +1, indicating that it loses electrons and is oxidized.

- Bromine goes from an oxidation number of 0 to -1, indicating that it gains electrons and is reduced.

C. The oxidizing agent is the substance that causes another substance to be oxidized. In this reaction, bromine is the oxidizing agent because it causes potassium to lose electrons (undergo oxidation).

Final answer:

In the reaction 2K + Br2 → 2KBr, K is oxidized from an oxidation number of 0 to +1 and Br2 is reduced from 0 to -1. Br2 is the oxidizing agent as it gains electrons; K is the reducing agent as it loses electrons.

Explanation:

To answer the question about the chemical reaction 2K + Br2 → 2KBr:

Assigning oxidation numbers: Potassium (K) has an oxidation number of 0 as a pure element, and Bromine (Br2) also has an oxidation number of 0 as a diatomic molecule. In the product, potassium bromide (KBr), K has an oxidation number of +1 and Br has an oxidation number of -1.

Identifying what is oxidized and what is reduced: Potassium (K) is oxidized because its oxidation number increases from 0 to +1. Bromine (Br2) is reduced because its oxidation number decreases from 0 to -1.

Determining the oxidizing agent and reducing agent: The oxidizing agent is Bromine (Br2), because it gains electrons and is reduced to Br- ions. The reducing agent is Potassium (K), as it loses electrons and is oxidized to K+ ions.

What is the molar concentration of [H3O+] in a cola that has a pH of 3.120?

Answers

Final answer:

The molar concentration of [H3O+] in a cola with a pH of 3.120 is approximately 7.92 x 10^(-4) M.

Explanation:

The molar concentration of [H3O+] in a cola with a pH of 3.120 can be determined using the equation:

pH = -log[H3O+]

First, we need to convert the pH to a hydronium ion concentration. Using the given pH of 3.120, we can rearrange the equation and solve for [H3O+]:

[H3O+] = 10^(-pH)

Plugging in the pH value, we get:

[H3O+] = 10^(-3.120)

Calculating this, we find that the molar concentration of [H3O+] in the cola is approximately 7.92 x 10^(-4) M.

please compare the energies of excitation and emission for fluorescence. Which is greater and why?

Answers

Answer:

The excitation energy is always greater than the emission energy .

Explanation:

When a molecule absorbs energy, electrons are excited from the ground state (S₀) to different vibrational levels of the excited state (S₁) in about 1 fs.

In the next picosecond, most of them will drop to the lowest vibrational level of S₁.

They remain there for about 10 ns, and then they drop to different vibrational levels of S₀.

The excitation energy is always greater than the emission energy because excitation occurs from the ground state of S₀ to a higher vibrational level of S₁, while emission occurs from the lowest vibrational level of S₁ to a higher vibrational of S₀.

The excitation energy of fluorescence is greater than the emission energy.

What is excitation energy?

Excitation has to do with absorption of energy by a ground state molecule in (S₀) moving it to a different vibrational levels  (S₁) which is higher in about 1 fs.

It the subsequently drops in one picosecond, most of them will drop to the lowest vibrational level of S₁.

Note that excitation energy must be greater than emission energy owing to the fact that excitation begins at the ground state moving up to a higher vibrational level , while emission begins at the lowest vibrational level moving up to a higher vibrational levels.

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Which reaction represents cellular respiration?

a.sugar + oxygen → carbon dioxide water + atp

b.carbon dioxide + water + atp → sugar + oxygen

c.oxygen + carbon dioxide → sugar + water + atp

d.water + atp → carbon dioxide + sugar?

Answers

Answer:

A.sugar + oxygen → carbon dioxide water + atp

Explanation:

Cellular respiration is a process by which cells use organic compounds such as glucose in presence of oxygen to generate energy in the form of ATP, that is used to drive cellular processes such as transport.Cellular respiration generates ATP together with carbon dioxide and water as by products. The process mainly takes place in the mitochondria also known as the power house of the cell. The process occurs in three stages, namely; glycolysis, Kreb's cycle and electron transport chain.
Final answer:

Cellular respiration is a biological process whereby glucose (sugar) and oxygen are used to produce ATP (energy), with carbon dioxide and water as byproducts. This process consists of three main stages, Glycolysis, Krebs Cycle, and Electron Transport Chain. Thus, option A: 'sugar + oxygen → carbon dioxide + water + ATP' accurately represents cellular respiration.

Explanation:

In the realm of biology, the reaction that best represents cellular respiration is option A: sugar + oxygen → carbon dioxide + water + ATP. This is because, in the process of cellular respiration, glucose (sugar) and oxygen are utilized to generate energy in the form of ATP (Adenosine Triphosphate), while releasing carbon dioxide and water as byproducts.

Cellular respiration consists of three main stages: Glycolysis, Krebs Cycle (Citric Acid Cycle), and Electron Transport Chain. During these stages, energy is extracted from glucose and used to form ATP. Oxygen acts as the final electron acceptor in the process, ultimately leading to the formation of water.

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A skeleton equation shows just the reactants and products whereas a balanced equation shows the

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Answer:

A skeleton equation shows just the reactants and products whereas a balanced equation shows the relative amounts of, or proportion between, reactants and products.

Explanation:

The skeleton equation shows which reactants are being used and which products are being formed.

The reactants are shown on the left and the products are shown on the right side of the equations, separeted by an arrow.

For example, the skeleton equation to obtain water is:

H₂(g) + O₂(g) → H₂O (g)

From it you know that hydrogen and oxygen react to form water, yet you do not know in which ratio they do it.

Then, you balance the equation, adding the appropiate coefficients, to make the number of atoms of each kind on the reactant side equal to the number of the same kind of atoms on the product side.

This is, for the example of water, the number of hydrogen atoms on  the left must equal the number of atoms of hygrogen on the right side, and  the number of oxygen atoms of the left must equal the number of oxygen atoms on the right.

For the water example that is:

2H₂(g) + O₂(g) → 2H₂O (g)

Showing that 2 molecuies of hydrogen (or 4 atoms) react with 1 molecule of oxygen (or 2 atoms) to produce 2 molecules of water, and that proportion (relative amounts) will always be true for that reaction.

Complete each sentence using the drop-down menus.

Desertification mainly impacts resources.

Point and nonpoint sources refer to types of pollution.

The process of people moving to cities, called , greatly impacts land, air, and water resources.

The burning of fossil fuels can cause .

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Answer:

Desertification mainly impacts land  resources.

Point and nonpoint sources refer to types of water pollution.

The process of people moving to cities, called   urbanization , greatly impacts land, air, and water resources.

The burning of fossil fuels can cause smog and acid rain.

Explanation:

Final answer:

Desertification impacts natural resources. Point and nonpoint sources refer to types of water pollution. Urbanization has significant impacts on land, air, and water resources. The burning of fossil fuels can cause environmental pollution.

Explanation:

Desertification mainly impacts natural resources. This process refers to the degradation of once fertile land into barren desert due to factors such as climate change, deforestation, and overgrazing. It can lead to the loss of agricultural productivity, water scarcity, and biodiversity decline.

Point and nonpoint sources refer to types of water pollution. Point sources are specific and identifiable sources of pollution, such as pipes discharging industrial waste into a river. Nonpoint sources are diffuse sources, such as runoff from agricultural fields, that enter water bodies indirectly.

The process of people moving to cities, called urbanization, greatly impacts land, air, and water resources. Urbanization often leads to the conversion of agricultural land into concrete jungles, increased air pollution from vehicles and industries, and increased water demand and waste generation.

The burning of fossil fuels can cause environmental pollution. When fossil fuels, such as coal, oil, and natural gas, are burned for energy production or transportation, they release pollutants like carbon dioxide, sulfur dioxide, and nitrogen oxides. These pollutants contribute to air pollution, climate change, and acid rain.

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Equation to paragraph plzz

Answers

Answer:

AgNO₃₍aq₎₎ + NaCl ₍aq₎₎ --------> NaNO₃₍aq₎ + AgCl₍s₎

Explanation:

Silver Nitrate: AgNO₃

Sodium Chloride: NaCl

Sodium Nitrate: NaNo₃

silver(I) chloride: AgCl

Equation:

AgNO₃₍aq₎₎ + NaCl ₍aq₎₎ --------> NaNO₃₍aq₎ + AgCl₍s₎

Name two lab tools used to measure the volume of a liquid

Answers

Answer:

beaker and flasks

Explanation:

When kaolinite clay [al2(si2o5)(oh)4] is heated to a sufficiently high temperature, chemical water is driven off?

Answers

Final answer:

Heating kaolinite clay results in the removal of hydroxyl groups as water in a process known as dehydroxylation, producing metakaolin and eventually aluminum oxide (Al2O3).

Explanation:

When kaolinite clay, which has the formula Al2(Si2O5)(OH)4, is heated to a high temperature, it undergoes a process known as dehydroxylation. This process involves the removal of hydroxyl groups as water, which is referred to as 'chemical water'.

When heated sufficiently, the kaolinite loses water molecules and forms metakaolin, an intermediate phase before it eventually transforms into aluminum oxide (Al2O3), also known as alumina. Alumina is important as it is a precursor for aluminum production through the electrolysis of aluminum ions in a solution containing cryolite (Na3AlF6) and calcium fluoride (CaF2).

If a sample of a gas has an initial volume of 15 L and a pressure of 125 kPa what will the pressure of the gas be (in atm) if the volume is increased to 29 L?

Answers

apply Boyle's law

Boyle's Law, an ideal gas law which states that the volume of an ideal gas is inversely proportional to its absolute pressure at a constant temperature

V = 1/P

PV = 1

PV= constant

let 15L = V1 and 125kPa = P1

9L =V2 and P2 = ?

Now from Boyle's law

P1V1 = P2V2

Substitute the values

15L * 125kPa = 29 * P2

P2 = 64.65kPa

convert Pascal's into atm

1 pascal =

9.869 × 10-6 atmosphere

P2 = 64.65 *10^3 *9.869 × 10-6 (kPa is kilo Pascal's)

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