What is limit and exposure?

Answer: Handwashing. It is estimated that washing hands with soap and water could reduce diarrheal disease-associated deaths by up to 50% 1. Researchers in London estimate that if everyone routinely washed their hands, a million deaths a year could be prevented 2.

Explanation:

Chlorine will lose 7 electrons when it forms an ion. The correct answer is option C)

An atom forms an ion either by gaining or losing electrons. Chlorine is a non-metal element which is located in the 7th group of the periodic table. It has seven valence electrons and requires only one electron to complete its octet. Chlorine can gain or lose electrons to form an ion. Chlorine has a strong tendency to gain electrons as compared to losing them. Therefore, it needs to gain one electron to complete its octet. However, the ion formed by the loss of electrons is more stable than the ion formed by the gain of electrons.

The ion formed by chlorine is Cl⁻ . When chlorine gains one electron, its electronic configuration becomes 1s² 2s² 2p⁶ 3s² 3p⁶. This configuration is the same as that of argon, the nearest noble gas. Hence, chlorine has a greater tendency to lose electrons and form Cl⁻  ion. The ion formed by chlorine is Cl⁻ . The Cl⁻  ion has 18 electrons, of which 10 electrons are located in the inner shells. Therefore, the ion has 8 valence electrons and is electronically stable. Chlorine loses 7 electrons to complete its octet and forms Cl⁻ ion.

Thus, Chlorine will lose 7 electrons when it forms an ion. The correct answer is option C)

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Answer:

B

Explanation:

this is called peer review and your results will be stronger

The U.S. Treasuries act as benchmark bonds implies that they're measured in terms of the spread with regards to other treasuries.

A benchmark bond simply means the standard measure of the risk of a bond against the other bonds.

When we say that U.S. Treasuries act as benchmark bonds we mean that yields on other bonds are measured in terms of the spread over treasuries.

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The units of concentration in Part A are mols/L and mmols/L, while the unit of volume in Part B is liters

Part A: The concentration of KCl can be calculated by dividing the amount of KCl in grams by its molar mass (in grams/mol) and then dividing by the volume in liters. Given that 37 grams of KCl is added to 0.5 L of distilled water, we divide 37 grams by the molar mass of KCl (74.55 g/mol) to obtain the number of moles.

Then, divide the number of moles by the volume in liters to obtain the concentration in mol/L. To express the concentration in mmols/L, multiply the concentration in mol/L by 1000.

Part B: Blood constitutes approximately 7% of the body weight. To determine the volume of blood in liters for an 85 kg person, we multiply the body weight (85 kg) by the blood percentage (7%) and divide the result by 100.

This calculation provides the volume of blood in kilograms. Since 1 liter of water is equivalent to 1 kilogram, the calculated value represents the volume of blood in liters.

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Answer:

IT should be Fe2O3

Explanation:

Fe2O3

Answer:

 Iron (III) Oxide = Fe2O3

Answer: a. 1.11 atm, 0.43 mol

Explanation:

Science affected our lives at the beginning of this pandemic.

Explanation:

Although scientists did study the virus to see how deadly it is the pandemic kept spreading. The spreading of the virus was not the scientist's fault it was the citizens' fault. They now found a vaccine that took hard work and a short amount of time.

The value of the equilibrium constant, K', at 25°C for the reversed and multiplied reaction is 0.1775.

The equilibrium constant, K, represents the ratio of product concentrations to reactant concentrations at equilibrium for a given chemical reaction. When the reaction is reversed, the equilibrium constant is inverted. In this case, the given equilibrium constant, K, is 0.355.

To determine the value of K' for the reversed reaction, we take the reciprocal of K: 1/K. Thus, 1/0.355 = 2.8169. However, since the reaction is also multiplied by a factor of 2, we need to square the calculated value. So, (2.8169)^2 = 7.9189.

Therefore, the value of the equilibrium constant, K', for the reversed and multiplied reaction is approximately 7.9189. It indicates that at 25°C, the concentration of products is significantly favored over the reactants in the equilibrium state.

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Which salts, when dissolved in water, will produce an acidic solution among NH4Cl, KHSO4, and NaCN? The main d) 1 and 2.

1) NH4Cl - Ammonium chloride dissociates into NH4+ and Cl- ions in water. The NH4+ ion further reacts with water to form NH3 (ammonia) and H3O+ (hydronium), thereby increasing the concentration of H3O+ and producing an acidic solution.
NH4+ + H2O -> NH3 + H3O+

2) KHSO4 - Potassium hydrogen sulfate dissociates into K+ and HSO4- ions in water. The HSO4- ion reacts with water to form H2SO4 (sulfuric acid) and OH- ions, which increases the concentration of H3O+ and leads to an acidic solution.
HSO4- + H2O -> H2SO4 + OH-

3) NaCN - Sodium cyanide dissociates into Na+ and CN- ions in water. CN- ion reacts with water to form HCN (hydrogen cyanide) and OH- ions, which results in an increase in OH- ions and produces a basic solution.
CN- + H2O -> HCN + OH-

Hence, only NH4Cl and KHSO4 will produce acidic solutions when dissolved in water.

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To tell a Cu(NO3)2 solution from a Ni(NO3)2 solution, you can add KI to the solution. If the solution contains Cu(NO3)2, the brown precipitate will be formed, but if the solution contains Ni(NO3)2, no precipitate will be formed.

This is the best way to distinguish between these two solutions, since adding KOH or Na2C2O4 will result in blueish precipitates, being harder to identify if it is Cu(NO3)2 or Ni(NO3)2 and with Na2SO4 no reaction will happen.

It means that the answer is: By adding KI and seeing if a brown precipitate is formed.

Answer:

t = 42.4 years

Explanation:

To find the amount of time needed for the sample to decay, you need to use the half-life equation:

\(N(t) = N_0(\frac{1}{2})^{t/h}\)

In this equation,

-----> N(t) = final mass (mg)

-----> N₀ = initial mass (mg)

-----> t = time passed (yrs)

-----> h = half-life (yrs)

You can find how much time passed by plugging the given variables into the equation and solving for "t". The final answer should have 3 sig figs like the given values.

N(t) = 9.38 mg                       t = ? yrs

N₀ = 25.0 mg                        h = 30.0 yrs

\(N(t) = N_0(\frac{1}{2})^{t/h}\)                                <----- Half-life equation

\(9.38mg = 25.0mg(\frac{1}{2})^{t/30.0yrs}\)              <----- Insert variables

\(0.3752 = (\frac{1}{2})^{t/30.0yrs}\)                          <----- Divide both sides by 25.0 mg

\(ln(0.3752) = ln((\frac{1}{2})^{t/30.0yrs})\)              <----- Take the natural log of both sides

\(ln(0.3752) = \frac{t}{30.0yrs} ln(\frac{1}{2})\)                   <----- Rearrange the exponent

\(-9.803 = \frac{t}{30.0yrs} (-0.6931)\)                 <----- Solve the natural logs

\(1.1414= \frac{t}{30.0yrs}\)                                  <----- Divide both sides by -0.6931

\(42.4 yrs= t\)                                        <----- Multiply both sides by 30.0 yrs

Answer: Nobel Gasses

Explanation:

The element that is most easily oxidized among Sn, Cu, and Mg is Sn. So, the correct answer is (B) Sn.

Based on the activity series given, we can determine the element that is most easily oxidized among Sn (tin), Cu (copper), and Mg (magnesium).

The activity series lists the elements in order of their reactivity, with the most reactive element at the top and the least reactive at the bottom. The element that is most easily oxidized is the one that readily loses electrons and forms positive ions.

Looking at the activity series, we can see that Sn appears above Cu and Mg. This indicates that Sn is more easily oxidized than Cu and Mg. In other words, Sn has a higher tendency to lose electrons and form Sn2+ ions compared to Cu and Mg.

On the other hand, Cu appears below Sn and above Mg, which means it is less easily oxidized than Sn but more easily oxidized than Mg. Similarly, Mg appears at the bottom of the activity series, indicating that it is the least easily oxidized among the three elements.

Therefore, the element that is most easily oxidized among Sn, Cu, and Mg is Sn. So, the correct answer is (B) Sn.

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In a voltaic cell is constructed concentration of reactants will decrease while concentration of products will increase--this will continue until equilibrium is reached.

The larger concentration enables the rise in voltage difference in an electrochemical cell. increased voltage is seen as a result of the reaction moving more quickly in a forward direction due to the increased reactant concentration.

When a voltaic cell is built, the concentration of the reactants will drop while the concentration of the products will rise; this process will go on until equilibrium is established.

A voltaic cell has two electrodes—one in each half-cell. Reduction happens at the cathode, whereas oxidation happens at the anode. These electrochemical processes are occurring on metal electrodes or surfaces.

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Answer:

6 valence electrons

Explanation:

The atom you have given is a sulfur atom. It has 6 valence electrons.

I'm hoping the same for my new coaching classes

This is my first time going out to study ngl-

Answer:

Heterogeneous mixture because it is not soluble and in non uniform texture.

Answer:

Explanation: Every electron has a single negative(-) charge, the addition of two electrons results in an oxygen ion with a charge of negative(−)2. This is  in fact true of every element located under oxygen in the periodic table.

P.S. hope this helps :)

a) Friction loss in pipe fittings.

Minor losses in a fluid system refer to the head loss or pressure drop that occurs due to a variety of factors, including changes in the flow direction, obstructions, contractions, expansions, and bends in the pipeline, and other fittings such as valves, elbows, tees, and reducers. These changes in the flow path cause turbulence and eddies that result in additional frictional losses, which increase the overall head loss in the system.

While minor losses may occur due to low flows or measurement inaccuracies, these factors are not typically considered the primary causes of head loss in fluid systems. The primary source of minor losses is the frictional resistance that occurs at pipe fittings due to the changes in flow direction and other obstructions in the flow path.

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Answer:

Ne

Explanation:

Neon is the element with the most stable outer electron configuration because it has eight valence electrons that fill the outer shell. Eight electrons in the outer shell is the most stable arrangement of electrons. Neon is also a noble gas which means that due to it already having a complete outer shell, it doesn't lose, gain, or share electrons. Therefore, it is stable.

Hope that helps.

The volume of dry hydrogen gas at STP can be determined by subtracting the vapor pressure of water at the given temperature from the total pressure and then using the combined gas law to calculate the volume.

In this case, with 2.50 L of hydrogen gas collected over water at 40 °C and 767 mm Hg, and a vapor pressure of water at 40 °C being 55.3 mm Hg, the volume of dry hydrogen gas at STP can be calculated.

To determine the volume of dry hydrogen gas at STP, we need to consider the effect of water vapor pressure. At the given temperature of 40 °C, the vapor pressure of water is 55.3 mm Hg. Since the collected hydrogen gas is over water, the total pressure observed is the sum of the pressure of hydrogen gas and the vapor pressure of water, which is 767 mm Hg.

To calculate the volume of dry hydrogen gas at STP, we need to subtract the vapor pressure of water from the total pressure. The pressure due to the dry hydrogen gas alone is then 767 mm Hg - 55.3 mm Hg = 711.7 mm Hg.

Using the combined gas law, which states that the product of the pressure and volume of a gas is proportional to the temperature, we can set up the following equation:

(P1 * V1) / T1 = (P2 * V2) / T2

At STP, the temperature (T2) is 273 K, and the pressure (P2) is 1 atm. Rearranging the equation, we have:

V2 = (P1 * V1 * T2) / (P2 * T1)

Plugging in the values, we get:

V2 = (711.7 mm Hg * 2.50 L * 273 K) / (1 atm * 313.15 K)

Simplifying the equation, we find:

V2 ≈ 623.6 L

Therefore, the volume of dry hydrogen gas at STP is approximately 623.6 L.

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All statements given in the question are incorrect except for 1 statement. The correct statement is:1 s = 10^3 ms.

In the question, we have been provided with 5 statements. We are asked to select all the correct statements from those 5 statements. Given below are for each statement:1 g = 10^3 mg:This is incorrect. 1 g is equal to 1000 mg.10^-3 g = 10^12 ng:This is incorrect. 10^-3 g is equal to 1 mg.1 km = 10^5 mm:This is incorrect. 1 km is equal to 1,000,000 mm.1 s = 10^6 μs:This is incorrect. 1 s is equal to 1,000,000 μs.1 s = 10^3 ms:This is correct. 1 s is equal to 1000 ms.Therefore, the main answer to this question is that only 1 statement is correct, which is:1 s = 10^3 ms.

Metric units are based on the power of ten. The base units of the International System of Units (SI) are the meter, kilogram, second, kelvin, ampere, mole, and candela. All other metric units can be derived from these basic units.The first unit in each conversion is in grams, seconds, or kilometers. The metric units for millimeters, microseconds, and nanograms are derived from these basic units. One gram is equal to 1000 milligrams (mg), 1 second is equal to 1000 milliseconds (ms), and 1 kilometer is equal to 1000000 millimeters (mm). 10^-3 g is equal to 1 milligram (mg), 10^6 μs is equal to 1 second (s), and 10^12 ng is equal to 1 gram (g).

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Density is defined as mass of the given matter divided by its volume

it's  SI unit is kg/m³

given,  density = 6.8 grams per cubic centimeter (g/cm³)

mass = 5.3 grams (g).

D = M ÷ V

V = M ÷ D

V = 5.3 ÷ 6.8

V = 0.77941 g/cm³

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The presence of the amino group in amino acids allows for resonance stabilization of the carboxylic acid group, leading to a greater acidity compared to acetic acid.

The carboxylic acid groups of amino acids are more acidic than a carboxylic acid like acetic acid because of the presence of the amino group in amino acids. This presence of the amino group influences the acidity of the carboxylic acid group through a process called resonance stabilization.

In amino acids, the amino group (-NH2) can donate electrons to the carboxylic acid group (-COOH) through resonance. This donation of electrons leads to the formation of a negatively charged oxygen atom in the carboxylic acid group, which increases its acidity. This negatively charged oxygen atom can easily donate a proton, resulting in a lower pKa value.

On the other hand, in acetic acid, there is no amino group present to donate electrons through resonance. Therefore, the carboxylic acid group in acetic acid is not as easily deprotonated, resulting in a higher pKa value compared to the carboxylic acid groups of amino acids.

To summarize, the presence of the amino group in amino acids allows for resonance stabilization of the carboxylic acid group, leading to a greater acidity compared to acetic acid. This is why the carboxylic acid groups of amino acids have a lower pKa value of around 2, while acetic acid has a pKa value of 4.76.

The question should be:

Why are the carboxylic acid groups of the amino acids so much more acidic ( pKa ~ 2 ) than a carboxylic acid such as acetic acid ( pKa = 4.76)

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Answer:

0.241 M

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

HBr + NaOH —> NaBr + H₂O

From the balanced equation above,

The mole ratio of acid, HBr (nₐ) = 1

The mole ratio of base, NaOH (n₆) = 1

Finally, we shall determine the concentration of the NaOH solution. This can be obtained as follow:

Volume of base, NaOH (V₆) = 20 mL

Volume of acid, HBr (Vₐ) = 24.1 mL

Concentration of acid, HBr (Cₐ) = 0.2 M

Concentration of base, NaOH (C₆) =?

CₐVₐ / C₆V₆ = nₐ/n₆

0.2 × 24.1 / C₆ × 20 = 1/1

4.82 / C₆ × 20 = 1

Cross multiply

C₆ × 20 = 4.82

Divide both side by 20

C₆ = 4.82 / 20

C₆ = 0.241 M

Therefore, the concentration of the NaOH solution is 0.241 M