Number of
Protons
Number of
Neutrons
Atomic
Number
Mass
Number
Element
(symbol)
20
20
A
B
С
9
D
E
19
F
Using the periodic table, complete the table to describe each atom. Type in your answers.
А
B
С
1 0
]

Answer:

pH strips and written observations of stream water

Explanation:

To classify the statements based on the described method, we need to understand the definitions of each term. Standard addition is a method where a known amount of standard solution is added to a sample to determine its concentration. Internal standards involve adding a known amount of a substance to the sample, which is used as a reference to determine the concentration of other substances. External standards involve comparing the sample to a known concentration standard.
With that in mind, the statement that describes the method of standard addition is "Standard addition." The statement that describes the method of internal standards is "Internal standards." Finally, the statement that describes the method of external standards is "External standards."

Standard addition is a method used in analytical chemistry to improve the accuracy of quantitative measurements. It involves adding known amounts of a standard solution to the sample, and then comparing the response of the sample-plus-standard mixture to the response of the sample alone.
Internal standards are compounds added to a sample in known amounts, allowing for the correction of variations in the analytical process. They are chemically similar to the analyte of interest and help improve precision by accounting for errors due to factors such as instrument fluctuations or sample preparation.
External standards are reference materials with known concentrations of the analyte, which are used to create a calibration curve. By measuring the response of the external standards, the concentration of the analyte in the sample can be determined by comparing the sample's response to the calibration curve.

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Nitrous acid is the chemical name for HNO₂ and it is its systematic name.

Nitric acid has the chemical formula HNO₃. Compared to nitrous acid, it is more potent and stable. This is due to the fact that its conjugate base is more stable than that of nitrous acid. H₂N₂O₂ is the chemical formula for hyponitrous acid. HNO₂ is a wobbly, unstable, and mildly acidic substance. It is sometimes referred to as a nitrogen oxoacid. Its molecular weight is 47 g/mol. HNO₂ has a boiling point of 158°C.

Nitrous acid is commonly produced by acidifying nitrite salt with mineral acid. As a result, nitrous acid is the chemical term or the systematic name for HNO₂.

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Answer : The original volume of gas is \(365cm^3\)

Explanation :

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

\(\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\)

where,

\(P_1\) = initial pressure of gas = 800 torr

\(P_2\) = final pressure of gas at STP = 760 torr

\(V_1\) = initial volume of gas = ?

\(V_2\) = final volume of gas at STP = \(450.0cm^3\)

\(T_1\) = initial temperature of gas = \(-40^oC=273+(-40) =233K\)

\(T_2\) = final temperature of gas at STP = \(0^oC=273+0=273K\)

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

\(\frac{800torr\times V_1}{233K}=\frac{760torr\times 450.0cm^3}{273K}\)

\(V_1= 364.8cm^3\approx 365cm^3\)

Therefore, the original volume of gas is \(365cm^3\)

The volume of 0.130 M NaOH required to adjust the pH of the solution to 2.63 is 15.4 mL.

pH = pKa + log([A-]/[HA])

[H+] = \(10^{-pH}\) = \(10^{-2.63}\) = 1.33 x \(10^-3\)M

Using the equation for the dissociation constant of a weak acid, we can calculate the concentration of A-:

Ka = [H+][A-]/[HA]

Ka = \(10^{-pKa1}\) = 1.67 x \(10^-3\)

[A-]/[HA] = Ka/[H+] = 1.67 x \(10^-3\) / 1.33 x \(10^-3\) = 1.256

[A-] = [HA] x 1.256 = 0.026 M

Now we can use the Henderson-Hasselbalch equation to calculate the required volume of NaOH to adjust the pH to 2.63. At pH 2.63, the ratio of [A-]/[HA] should be equal to \(10^(pH-pKa1)\)= 1.63 x 10³:

1.63 x 10³ = [A-]/[HA] = ([0.026 + x]/0.12)/(0.021)

where x is the amount of NaOH (in moles) added to the solution. Solving for x, we get:

x = 0.12 * 1.63 x 10³ * 0.021 - 0.026 = 0.002 M

To convert moles of NaOH to milliliters of a 0.130 M solution, we can use the following equation:

moles NaOH = Molarity x volume (in liters)

0.002 M = 0.130 M x (volume / 1000)

volume = 15.4 mL

pH is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (base 10) of the concentration of hydrogen ions (H+) in a solution. The pH scale ranges from 0 to 14, with a pH of 7 being considered neutral. A pH below 7 indicates acidity, with lower numbers indicating greater acidity, while a pH above 7 indicates alkalinity, with higher numbers indicating greater alkalinity.

Acids are substances that donate H+ ions, increasing the concentration of H+ in a solution and lowering its pH. Bases, on the other hand, are substances that accept H+ ions, decreasing the concentration of H+ and raising the pH. The pH of a solution can have a significant impact on chemical reactions and biological processes, as many enzymes and other biomolecules are sensitive to changes in pH. Therefore, maintaining the appropriate pH is crucial in many chemical and biological applications.

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Answer:

Explanation:

A is the correct answer.

If you found my answer useful then please mark me brainliest

Answer:

I put this so the guy up top can have brainliest

Explanation:

your welcome

Answer:

62 L

Explanation:

We are given that:

n = 2.3 mol

R = 0.082 L*atm/(mol*K), the ideal gas constant in the required units

T = 290 K

P = 0.89 atm.

therefor:

V = nRT/P

= [(2.3 mol)(0.082 L*atm)(290 K)/(mol*K)]/(0.89 atm)

= 62 L

The volume of 2.3 mol CL2 will be 62 L.

A three-dimensional element's area of coverage. The measurement of volume is done in cubic units. Decibels are a unit of measurement for the volume of sound.

Calculation of volume.

Volume can be determined by using the formula.

PV = nRT

where, P = pressure, V = volume, n = number of moles, R = gas constant and T = temperature,

It is given that, n = 2.3 mol, T = 290 K and P = 0.89 atm.

Put the value of given data in volume equation,

V = n RT/ P

V = 2.3 mol × 0.082 × 290 /0.89

V = 62 L.

Therefore, the volume will be 62 L.

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Answer:

the forth one i think

Explanation:

The electron-pushing mechanism for the decarboxylation reaction involves the addition of three curved arrows.

In the decarboxylation reaction, a carboxylic acid group (-COOH) is removed from a molecule, resulting in the formation of a carbon-carbon double bond. This process typically occurs under specific conditions, such as heating or the presence of a catalyst. To illustrate the electron-pushing mechanism for this reaction, let's consider the decarboxylation of a generic carboxylic acid represented as R-COOH.

First, we start with the carboxylic acid molecule (R-COOH) and focus on the carbon-oxygen bond of the carboxyl group. We can add the first curved arrow, which starts at the carbon atom, represents the movement of a lone pair of electrons, and ends at the oxygen atom of the carboxyl group. This curved arrow indicates the electron flow from the carbon atom towards the oxygen atom.

Next, we consider the oxygen atom's lone pair of electrons. We can add the second curved arrow, which starts at the oxygen atom, represents the movement of the lone pair of electrons, and ends at the adjacent carbon atom. This curved arrow indicates the electron flow from the oxygen atom towards the adjacent carbon atom.

Finally, we focus on the carbon-carbon bond adjacent to the carboxyl group. We can add the third curved arrow, which starts at the carbon atom on the other side of the carbon-carbon bond, represents the movement of a lone pair of electrons, and ends at the adjacent carbon atom. This curved arrow indicates the electron flow from the carbon atom towards the adjacent carbon atom, resulting in the formation of a carbon-carbon double bond.

Overall, the three curved arrows demonstrate the electron-pushing mechanism for the decarboxylation reaction, showing the movement of electron pairs and the formation of a carbon-carbon double bond.

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Answer:

358 \( {}^{o} c\)

Answer:

the correct answer to the question is i 358°C

Answer:

C. pH > pOH; Kw = 1.0 * 10^-14

Explanation:

The ion product of water, Kw = [H+]*[OH-] = 1.0 * 10^-14. It is a constant.

When an acid or base is added to water, its ion product does not change as it a constant. However, the relative concentrations of H+ ions and OH- ions will change depending on whether an acid or base is added to water.

When an acid is added to water, the concentration of H+ ions increases while that of OH- ions decreases, and vice versa.

Therefore, in the above situation where an acid is added to water, pH > pOH; Kw = 1.0 * 10^-14

The states of matter of the materials;

1) Dispersion forces - Yes

2) Hydrogen bonding - No

3) Ionic - No

4) Dispersion forces - No

5)  Dispersion forces - Yes

6) Ionic  - No

7) Hydrogen bonding - No

Sublimation is a physical process in which a substance transitions directly from its solid phase to its gaseous phase without passing through the intermediate liquid phase. In sublimation, the solid substance is heated, and the resulting gas molecules escape from the solid lattice structure without the need for melting.

One common example of sublimation is the process of dry ice. Dry ice is solid carbon dioxide (CO2) that sublimes at a temperature of -78.5 degrees Celsius (-109.3 degrees Fahrenheit). When dry ice is exposed to room temperature, it transitions directly from a solid to a gas, producing a fog-like effect.

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Answer:

the answer is b Li + Cl2 .....

Answer:

answer is true

Answer:

True

Explanation:

The weak acids are HNO₂ and HF. Option D is correct.

HNO₂ (nitrous acid) and HF (hydrofluoric acid) are considered weak acids because they only partially dissociate in water, resulting in a relatively low concentration of H⁺ ions in solution. On the other hand, HNO₃ (nitric acid) and H₂PO₄⁻ (dihydrogen phosphate) are strong acids, which fully dissociate in water, producing a high concentration of H⁺ ions.

On the other hand, HNO₃ (nitric acid) and H₂PO₄⁻ (dihydrogen phosphate) are both strong acids;

HNO₃ is a strong acid that fully dissociates in water, resulting in a high concentration of H⁺ ions.

H₂PO₄⁻ is a weak acid in its conjugate acid form (dihydrogen phosphate), but as H₂PO₄⁻, it acts as a weak base rather than a weak acid.

Hence, D. is the correct option.

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The muscles break down glycogen into glucose which undergoes glycolysis . the end product of glycolysis in active muscles is lactate, which is transported in the blood. the liver uses energy from fally acid oxidation drive glucose. the glucose produced in the liver is transported to muscle in the bloodstream.

muscles breaks into glycogen and glucose. the lactate is always the end product in glycolysis. by the fally acid oxidation liver uses energy. the cori cycle is the metabolic pathway which involves the active muscles and the  liver. so, the fatty acid will react and it forms the carbon dioxide and the water.

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The acid dissociation constant Ka of the acid is 3.9 × 10⁻⁵M.

Let's take the acid as HA. Its dissociation reaction can be represented as:

HA → H⁺ + A⁻

At equilibrium, the concentration of undissociated acid will be: [HA]

At equilibrium, the concentration of dissociated acid will be: [A⁻]

Initial concentration of HA is 0.099M.

Since the acid is 0.063% dissociated, the concentration of A⁻ ions formed will be:

0.063/100 × 0.099M = 0.00006237M

Therefore, [HA] = 0.099 - 0.00006237 = 0.09893763M

To calculate the dissociation constant of the acid, we will use the expression for Ka:

Ka = [H⁺][A⁻]/[HA]

Since we have already calculated the values of [A⁻] and [HA], we only need to determine the concentration of H⁺ ions.

To do this, we will use the fact that the solution is dilute and hence, the concentration of H⁺ ions from the dissociation of water can be ignored.

So, we only need to consider the contribution of H⁺ ions from the dissociation of HA.

At equilibrium, the concentration of H⁺ ions will be equal to the concentration of A⁻ ions formed, which we have already determined to be 0.00006237M.

So, Ka = [H⁺][A⁻]/[HA] = (0.00006237)² / 0.09893763 = 3.93 × 10⁻⁵M (rounded to 2 significant figures)

Therefore, the acid dissociation constant Ka of the acid is 3.9 × 10⁻⁵M.

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The retention time for n-propyl benzene according to the first and second peak on the chromatogram is 193.50 seconds.

Distance of the first peak = 5.11 cm

Distance of the second peak = 7.88 cm

The equation for the retention time of a compound is given below:

Tr = (df - di)/v

where, Tr = retention time

df = distance travelled by the compound (in cm)

di = distance travelled by the solvent front (in cm)

v = flow rate of the mobile phase (in cm/s)

Therefore, Distance travelled by the compound (n-propyl benzene) = distance between the first and the second peak = 7.88 - 5.11 cm = 2.77 cm

Flow rate of the mobile phase is not given

Hence, let's assume it as 1 cm/s

Therefore, Retention time of n-propyl benzene,

Tr = (df - di) / v = 2.77 / 1 = 2.77 s = 277 centiseconds = 193.50 seconds (rounded off to two decimal places).

Hence, the retention time of n-propyl benzene is 193.50 seconds.

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The correct answer is D) 6.5 kJ. The explanation for this is as follows:When a reaction takes place against a vacuum (i.e., zero external pressure), no pressure-volume work is done. Thus, we can use the equation ΔE=q+w, where ΔE is the change in internal energy

, q is the heat absorbed or released, and w is the work done on or by the system. Since the question only asks for the work done, we can ignore q, which means ΔE=w. Therefore, we need to calculate the change in internal energy that occurs when the volume expands from 14 L to 50 L at constant temperature and pressure. This can be done using the ideal gas law, which states that PV=nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the absolute temperature. Since the temperature and pressure are constant, we can write:V1/n1=V2/n2where V1 and n1 are the initial volume and number of moles, and V2 and n2 are the final volume and number of moles. Since the reaction is unspecified, we don't know the number of moles, but we can assume it stays constant. Therefore:V1/V2=n1/n2=1/3.5714This means that the volume increases by a factor of 3.5714. Since work is equal to the negative of the change in internal energy (w=-ΔE), the work done is:W=-ΔE=-(nCvΔT)=-(nR/(γ-1)ΔT)where Cv is the molar heat capacity at constant volume, γ is the ratio of specific heats (Cp/Cv), and ΔT is the change in temperature. Since the temperature is constant, ΔT=0.

Therefore, W=0, and the main answer is A) 0 kJ.However, this is not the final answer, since the question specifies that the reaction takes place against a vacuum. This means that there is no external pressure acting on the system, which means that no pressure-volume work is done. Therefore, the main answer must be modified to take this into account. The work done by the system is equal in magnitude but opposite in sign to the work done by the surroundings. Since there are no surroundings in this case, no work is done by the system. Therefore, the final answer is A) 0 kJ.

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Answer: 80

Explanation:

12+6+1+1=20

20x4=80

Comparing the electronegativities of the two elements is one method of predicting the type of bond that will form between them.

Ionic bonds are produced between atoms of metals and non-metals where the metal loses an electron to complete its octet and the non-metal acquires that electron to complete its octet. Covalent bonds are formed when two atoms share electrons to complete their octets.

Ionic chemicals are bound together by ionic bonds, whereas covalent compounds are held together by strong covalent bonds. While covalent molecules are normally insoluble in water, ionic compounds are. Additionally, covalent molecules are typically more flammable than ionic ones.

If the electronegativity of the two atoms differs by enough to allow one to totally draw an electron away from the other, the connection is ionic.

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Answer:

coffee can be burnt

Explanation:

coffee can be burned when brewing. When an empty pot sits on the heating element in a restaurant coffee machine it can get very hot. When the first stream of a new brew cycle hits the bottom of the pot, boils off very quickly, producing a horrible smell and taste that infuses the entire pot.

Answer: The new concentration of a solution of \(CaSO_{3}\) is 0.2 M 10.0 mL of a 2.0 M \(CaSO_{3}\) solution is diluted to 100 mL.

Explanation:

Given: \(V_{1}\) = 10.0 mL,      \(M_{1}\) = 2.0 M

\(V_{2}\) = 100 mL,           \(M_{2}\) = ?

Formula used to calculate the new concentration is as follows.

\(M_{1}V_{1} = M_{2}V_{2}\)

Substitute the values into above formula as follows.

\(M_{1}V_{1} = M_{2}V_{2}\\10.0 mL \times 2.0 M = M_{2} \times 100 mL\\M_{2} = 0.2 M\)

Thus, we can conclude that the new concentration of a solution of \(CaSO_{3}\) is 0.2 M 10.0 mL of a 2.0 M \(CaSO_{3}\) solution is diluted to 100 mL.

Examples of agroecology method use are in Burkina Faso are conservation tillage, green manures, natural fertilisers, biological predators and so on.

Agroecology refer to an approach that use ecological processes in agricultural production systems.

The benefits of Agroecology is that it help to protect, restore and also improve agriculture and food systems when there is climate shocks and unfavorable weather conditions.

Therefore, Examples of agroecology method use are in Burkina Faso are conservation tillage, green manures, natural fertilisers, biological predators and so on.

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(A) The statement "the products of photosynthesis are carbon dioxide (CO₂) and water (H₂O)" is false.

(B) The statement "Upwelling of deep, cold, nutrient-rich waters is the only way for nutrients to reach coastal surface waters " is true.

(C) The statement "Pressure systems in the Southern Hemisphere rotate clockwise" is false.

(A) The products of photosynthesis are not carbon dioxide (CO₂) and water (H₂O). Rather, they are glucose (C₆H₁₂O₆) and oxygen (O₂). During photosynthesis, plants and other photosynthetic organisms use sunlight, carbon dioxide from the atmosphere, and water from the environment to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells.

(B) Upwelling of deep, cold, nutrient-rich waters is indeed one of the ways for nutrients to reach coastal surface waters. Upwelling refers to the upward movement of deep ocean waters to the surface. In many coastal areas, particularly along the western coastlines of continents, winds and ocean currents cause the upward movement of cold, nutrient-rich waters from the ocean depths to the surface. This process brings essential nutrients such as nitrates and phosphates to the surface, which promotes the growth of phytoplankton and supports productive coastal ecosystems.

(C)  High-pressure systems in the Southern Hemisphere do not rotate clockwise. In the Southern Hemisphere, high-pressure systems rotate counterclockwise due to the Coriolis effect. The Coriolis effect is a result of the Earth's rotation, causing moving objects, including air masses, to be deflected to the left in the Southern Hemisphere. This deflection leads to counterclockwise circulation around high-pressure systems and clockwise circulation around low-pressure systems in the Southern Hemisphere. In the Northern Hemisphere, the circulation is reversed, with high-pressure systems rotating clockwise and low-pressure systems rotating counterclockwise due to the same Coriolis effect.

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Answer : Geela away is \(33.22\times 10^{15}\text{ miles}\)

Explanation :

As we are given that the alien tells you that it has traveled here from the planet Geela which is 5.670 × 10³ light years away.

And we know that:

\(1.06\times 10^{-16}\text{ light years}=6.21\times 10^{-4}\text{ miles}\)

Now we have to determine the distance away is Geela.

As, \(1.06\times 10^{-16}\text{ light years}=6.21\times 10^{-4}\text{ miles}\)

So, \(5.670\times 10^{3}\text{ light years}=\frac{5.670\times 10^{3}\text{ light years}}{1.06\times 10^{-16}\text{ light years}}\times 6.21\times 10^{-4}\text{ miles}\)

                                      = \(33.22\times 10^{15}\text{ miles}\)

Therefore, the Geela away is \(33.22\times 10^{15}\text{ miles}\)

Answer:

food

Explanation: