A chemist measures the amount of mercury in sediment samples from three areas of a river (the source, the midway point, and the
mouth).

Which is the most reasonable hypothesis for the chemist's experiment?

If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the mouth
and lowest at the source.

If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the mouth
and lowest at the midway point.

If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be the same all along
the river.

If a chemical plant near the source of the river is dumping mercury, then the mercury levels should be highest at the
source and lowest at the mouth.

The electricity generated that powers the watch by zinc in the battery combines with oxygen in the air, zinc oxide forms reaction is a product.

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This problem is providing the length in inches of a rod and it is being required to convert it to centimeters. According to the following, the answer will be 43.7 cm:

In science, we use units conversion to represent measurements in different types of units depending on a specific requirement. To do so, we use conversion factors based on equivalence statements, relating the required unit with the given one.

In this case, the equivalence statement between inches and centimeters is 2.54 cm = 1 in and we can use it to get the answer as shown below:

\(17.2in*\frac{2.54cm}{1in} \\\\=43.7 cm\)

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Answer:

Easy. You turn 250 mL into Liters which comes out to be 0.25. We now need moles so you multiply 0.25 L and 0.23 M of NaCl and you get 0.058 moles of NaCl. Now you need to turn moles into grams so 0.058 moles x 58.44 (NaCl molar mass) /1 mol and you get 3.39 grams of NaCl.

Explanation:

I might be wrong so good luck.

Answer:

It helps them to swim

I think this ans may help you

Answer:

:)

Explanation:

Water (chemical formula: H2O) is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is the major constituent of the fluids of organisms. As a chemical compound, a water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds.

Answer:

H2O

Explanation:

Thats the formula :P

According to the Brnsted-Lowry acid-base theory, HPO4 is the conjugate base of H2PO4 and is thus.

When atoms' ionic bonds are generated or ruptured, chemical events take place. The chemicals that initiate a chemical change are known as reaction mixture, while the regard to the structure as a result of the reaction as known as products.

An action made in response to anything is called a reaction. Your parents' reaction when you tell them you want to move out will show you how upset they are about it. The nature of a reaction is frequently physical. The behavior of a chemical when mixed with another material is referred to as a chemical reaction.

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Answer:

a 0.22L

Explanation:

Answer:

A

Explanation:

1 moles of oxygen is 0.044L

Answer:

See explanation

Explanation:

Double displacement reaction is a reaction in which the cations in the reactants side exchange partners on the product  side

The molecular equation here is;

CaI2(aq) + K2C2O4(aq) --------->CaC2O4(s) + 2KI(aq)

General ionic equation;

Ca^2+(aq) + 2I^-(aq) + 2K^+(aq) + C2O4^2-(aq) -------> CaC2O4(s) +  2I^-(aq) +

2K^+(aq)

Net ionic equation;

Ca^2+(aq) +  C2O4^2-(aq) ------> CaC2O4(s)

631.60 min will it take to raise the water temperature from 66.0 F to 149 F.

The temperature difference is 83 F degree that is in kelvin 301.484 k.

assume Q is the heat and t is the time so P = Q / t

where P is power

m = ρV

t = ( cm ΔT / P )

 = (ρcVΔT / P)

= ( 1000 * 4190 * 0.150 * 301.484 / 5000)

= 631.60 min

Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.

Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called centigrade), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI).

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Answer:

The three components of air are all classified as pure substances since they are not chemically bonded so they can be separated by certain processes and be present as a pure substance.

Explanation:

The components of air are all pure substances, the correct option is A.

A pure substance is a single type of matter that cannot be physically divided into other types of matter.

A pure substance has a known and consistent composition at all times.

A physical combination of two or more pure chemicals that maintain each substance's unique chemical identity is referred to as a mixture.

A pure material exists as a distinct entity. Mixtures are not pure substances, but elements and compounds are.

The characteristics of the mixture are sort of an average of the characteristics of the constituent ingredients.

The ingredients that make up a compound are substantially distinct from one another. However, a blend resembles the constituent parts.

Air is made up of different gases, such as oxygen, nitrogen, and carbon dioxide.

Air is a mixture of oxygen, nitrogen, and carbon dioxide, which are pure substances.

The statement that best describes the components of air is that they are all pure substances.

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Answer:

chemical change, because you are changing the actual molecules into differerent substances in a chemical way

Explanation:

The oxide of the metal with the highest atomic number, Thallium (Tl), should have the greatest lattice energy. The correct option is c.

Lattice energy refers to the energy released when ions come together to form a solid lattice structure. It is influenced by factors such as the charges of the ions and the distance between them. Generally, as the charges of the ions increase or the distance between them decreases, the lattice energy increases.

In this case, we are comparing the oxides of five metals: Gallium (Ga), Aluminium (Al), Thallium (Tl), Lead (Pb), and Indium (In). To determine which metal's oxide would have the greatest lattice energy, we consider their positions in the periodic table.

Thallium (Tl) has the highest atomic number among the given metals. As we move down a group in the periodic table, the atomic size increases due to the addition of more electron shells. Larger ions tend to have greater lattice energies because the increased distance between the charges is offset by the higher charges of the ions.

Therefore, the oxide of Thallium (Tl) is expected to have the greatest lattice energy among the given options. Option c. is the correct answer.

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During glycolysis and the citric acid cycle, electrons are passed from organic molecules to a molecule of NAD⁺ and FAD⁺ that results in the formation of ATP.

ATP (Adenosine triphosphate) is an organic molecule that is considered a main source of energy for many metabolic processes and is synthesized during cellular respiration by breaking down organic molecules.ATP synthase plays a significant role in the production of ATP.

ATP synthase is an enzyme located on the inner membrane of the mitochondria that helps to make ATP. It produces ATP by using the energy stored in a proton gradient formed by the electron transport chain. The energy released by this gradient drives the conversion of ADP (adenosine diphosphate) to ATP.

In glycolysis, glucose is converted into pyruvate by a series of chemical reactions. This process involves the use of ATP, which is synthesized from ADP and inorganic phosphate. During the conversion of glucose into pyruvate, electrons are passed from organic molecules to NAD+ (nicotinamide adenine dinucleotide) to form NADH. NADH then delivers these electrons to the electron transport chain, which ultimately leads to the production of ATP.

In the citric acid cycle, pyruvate is converted into acetyl-CoA, which then enters the citric acid cycle. During this cycle, electrons are passed from organic molecules to NAD+ and FAD (flavin adenine dinucleotide) to form NADH and FADH₂. These molecules then deliver these electrons to the electron transport chain, which ultimately leads to the production of ATP.

Overall, the transfer of electrons from organic molecules to molecules such as NAD+ and FAD in glycolysis and the citric acid cycle ultimately leads to the formation of ATP.

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Answer:

;,knbbbknnbkhbln bhbj k; b; m j

Explanation:

The substantial quantity of energy needed today places a constraint on the industrial manufacturing of fertilizers containing nitrogen.

The majority of the nitrogen, which makes up 78% of such air we breathe, is assumed to have been ultimately trapped in the pieces of primordial debris that formed early Earth. They formed as a result of their collision, and ever since then, their nutrient content has been leaking out along the melted cracks in the planet's crust.

The primary nitrogen source used in natural and anthropogenic sources is the combustion of natural fuels like coal and oil. Nitrogen may be deposited in the atmosphere as dry particulate, gases, and droplets or as a wet form such as rain, ice, hail, fog, & freezing rain.

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Answer:

4.031×\(10^{23}\)

Explanation:

You first need to calculate the number moles of NO2.  To do this use PV=nRT

STP stands for standard temperature and pressure which is 0 degrees C and 1 atm.

due to that:

P = 1 atm

V = 15 L

R = 0.08206 L*atm/mol*K

T = 273 K

n = unknown moles

solve for n to make the equation n=PV/RT

n=(1atm*15L)/(0.08206 Latm/molK*273K)

n=0.6696 mol of NO2

Then to find the number of molecules we use Avogadro's number which tells us the number of molecules per mol of a molecule or atom.

Avogadro's number is  6.02x10^23 molecules/mol

number of molecules = 0.6696mol × 6.02x10^23 molecules/mol

number of molecules = 4.031×10^23 molecules of NO2

Let me know if anything is not clear or if you get something else in the comments so that we can work it out.

Answer:

\(\large \boxed{\text{D.) 91 kPa}}\)

Explanation:

We can use the Ideal Gas Law — pV = nRT

Data:

V = 15.0 L

n = 0.55 mol

T = 300 K

Calculation:

\(\begin{array}{rcl}pV & =& nRT\\p \times \text{15.0 L} & = & \text{0.55 mol} \times \text{8.31 kPa$\cdot$ L$\cdot$K$^{-1}$mol$^{-1}\times$ 300 K}\\15.0p & = & \text{1370 kPa}\\p & = & \textbf{91 kPa}\end{array}\\\text{The pressure in the container is $\large \boxed{\textbf{91 kPa}}$}\)

Answer: 202.15

Explanation:

-71°C + 273.15

= 202.15K

Answer:

its a conductor

Explanation:

Conductors allow electricity to flow through them like metal wires

Answer: It is a conductor because a conductor allows electricity or heat to pass through and it is right because i took the quiz

Answer:

air

Explanation:

you breathe ok carbon dioxide

Answer:

Decompositon

Explanation:

Sodium chlorate → Sodium Chloride + Oxygen

Sodium chlorate is reactant.

Sodium chloride + Oxygen is the product.

Definition : -

Decomposition reaction is a chemical reaction in which a single reactant breaks down to simpler products.

The half-life for the transmutation of radon-222 to lead-214 is 3.8 days. If there is an initial mass of 100.0 g of radon-222, we can calculate how much radon-222 would remain after 7.6 days.

After one half-life (3.8 days), half of the radon-222 would decay. So, we are left with 50.0 g of radon-222. Now, after another 3.8 days (a total of 7.6 days), another half of the remaining radon-222 would decay. Therefore, we would have half of 50.0 g remaining, which is 25.0 g of radon-222 after 7.6 days.

The decay process follows an exponential decay model, where the remaining amount decreases by half with each half-life. By understanding the concept of half-life, we can determine the amount of radon-222 that would remain after a given time period. In this case, with an initial mass of 100.0 g and a half-life of 3.8 days, we calculate that 25.0 g of radon-222 would be left after 7.6 days.

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According to the mole concept, there are 0.2 moles of SO₄ in 19.20 grams of SO₄.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

Number of moles is given as mass/molar mass= 19.20/96=0.2 moles.

Thus, there are 0.2 moles of SO₄ in 19.20 grams of SO₄.

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The pH of the solution prepared by dissolving 2 aspirin tablets in enough water to make a 200 mL solution is approximately 2.44.

Acetylsalicylic acid (ASA) is a weak acid and will partially dissociate in water to form its conjugate base (acetylsalicylate ion) and hydronium ions (H+). The dissociation equation for ASA in water is:

ASA + H2O ⇌ H3O+ + A-

where ASA is acetylsalicylic acid and A- is the acetylsalicylate ion.

The equilibrium constant expression for this dissociation reaction is:

Ka = [H3O+][A-] / [ASA]

where Ka is the acid dissociation constant for ASA.

To determine the pH of the solution, we need to first calculate the concentration of the acetylsalicylic acid and the acetylsalicylate ion in the solution.

The number of moles of acetylsalicylic acid in 2 tablets can be calculated as:

n(ASA) = (2 tablets)(325 mg/tablet) / (180.16 g/mol) = 3.61 x 10^-3 mol

The total volume of the solution is 200 mL, which is equal to 0.2 L. Therefore, the concentration of ASA in the solution is:

\([ASA] = n(ASA) / V = 3.61 x 10^-3 mol / 0.2 L = 0.018 M\)

Assuming that all of the ASA dissociates into H3O+ and A-, the concentration of H3O+ and A- will be equal to each other and can be calculated using the equilibrium constant expression:

Ka = [H3O+][A-] / [ASA]

\([H3O+] = [A-] = sqrt(Ka x [ASA]) = sqrt(3.3 x 10^-4 x 0.018) = 3.61 x 10^-3 M\)

Finally, we can calculate the pH of the solution using the definition of pH:

\(pH = -log[H3O+] = -log(3.61 x 10^-3) = 2.44\)

Therefore, the pH of the solution prepared by dissolving 2 aspirin tablets in enough water to make a 200 mL solution is approximately 2.44.

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We have acquired a sense of measurement through millions of years of living because measurement is necessary for us to comprehend the outside world. Tools that supply scientists with a quantity are needed for measurements. Here the precision is 324 g. The correct option is A.

Accuracy is the capacity of an instrument to measure the precise value. In other words, it refers to how closely the measured value resembles a reference or genuine value. Small readings can be taken to increase accuracy. The calculation's inaccuracy is decreased by the little reading.

The precision of a substance is defined as the degree to which two or more measurements agree with one another. Here mass of object is 300 g and 324 g is close to it.

Thus the correct option is A.

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Answer:

Hard water is water that has high mineral content, Soft water is free from dissolved salts of such metals as calcium, iron, or magnesium

Explanation:

The species would be an anuran (an amphibian)

We need to answer this in English.

Here we want to find "A species that mates on the surface and then deposits its eggs in the water to be surrounded by sperm"

This would be known as a species of amphibian called an anuran, specifically a frog or toad.

Frogs and toads belong to the order Anura and have a characteristic reproductive cycle that involves external fertilization. During reproduction, the male releases his sperm into the water, and the female deposits her eggs in the water as well. The eggs are externally fertilized by sperm that swim around them. This process is known as external or external fertilization.

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The neutrons are the neutral sub-atomic particles present in the nucleus. The variation in the number of neutrons produces isotopes that have different atomic mass. Thus, options 1. d and 2. a are correct.

An isotope is said to be an atom of an element that have a different atomic mass but the same atomic number due to the variation in the neutrons in the nucleus. The neutrons have a neutral charge that makes the atom stable.

When a neutron is added or lost it makes the nucleus of the atom unstable leading to radioactive decay. The isotopes have the same constant number of protons in their nucleus.

The atomic number of the atom remains the same due to the stable proton number but varies the atomic mass due to the change in the number of neutrons.

Therefore, options d and a. neutrons and atomic mass are the correct blanks.

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Answer:

The correct answer -

a. Cd and Pb(NO3)2

b. Redox reactions

c. Pb and Cd(NO3)2

Explanation:

This is the reaction known as the redox or reduction-oxidation reaction of metals. In this particular reaction, there are two reactants Cadmium (III) in solid-state and lead (II) nitrate in the aqueous state. At the end of this reaction, the products that we get are lead (II) in solid-state and Cadmium (III) nitrate in the aqueous state.

cadmium (s)+ lead nitrate (aq) = lead (s) + cadmium nitrate (aq)

Cd (s) + Pb2+(aq) → Pb(s) + Cd2+(aq)

Here, Oxidizing agent is Pb2+ and the reducing agent is Cd.