Which properties change the composition of a substance? A physical properties
B chemical properties C chemical and physical properties D neither chemical nor physical properties

The two ways in which humans have negatively affected groundwater are Fertilizers and pesticides.

Fertilizers were chemical substances that are applied to crops in order to boost their yield.

Pesticides are chemicals that are being used to keep pests at bay. Herbicides, insecticides, nematicides, and molluscicides are examples.

Fertilizers and pesticides applied to the land, manure from livestock as well as other animals, landfills, mining operations, even unintended releases such as chemical spills or storage tank leaks are all factors that affect groundwater quality.

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Electron changes their spin to match the spin of proton in the nucleus. Hence, option C is correct.

Wavelength is the distance between identical points (adjacent crests) in the adjacent cycles of a waveform signal propagated in space or along a wire.

21-centimetre radiation, electromagnetic radiation of radio wavelength emitted by cold, neutral, interstellar hydrogen atoms. The hydrogen atom is composed of a positively charged particle, the proton, and a negatively charged particle, the electron. These particles have some intrinsic angular momentum called spin.

Hence, option C is correct.

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Answer:

How does the cuddle fish change its colors?

Please tell me if I'm wrong.

A chloride ion, Cl-, has the same electron configuration as a neutral atom of the element argon (Ar). Both have a complete outer electron shell with 8 electrons.

This is because a chloride ion is formed by the gain of one electron by a neutral chlorine atom (Cl), which has 7 electrons in its outermost shell. When it gains one electron, it completes its outer shell and becomes a chloride ion with the same electron configuration as argon. This electron configuration is stable and unreactive, which is why both argon and chloride ions do not readily form chemical bonds with other atoms or molecules. Overall, the electron configuration of a chloride ion is a result of its chemical properties and interactions with other atoms.

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Free energy change for transporting Ca2+ ions is calculated as follows:∆G = RT ln ([Ca2+]outside/[Ca2+]inside)∆G = 8.315 J/mol.K x 310 K x ln (25 mM/145 mM) = -15,400 J/mol.

Here, ∆G is negative, which implies that Ca2+ ions transport spontaneously from the cell to blood. This is because the free energy of the system decreases when Ca2+ ions move from high concentration to low concentration. Therefore, transporting Ca2+ ions is energetically favorable.

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Answer:

Explanation:

From the equation:

CO + 2H2 → CH3OH

Adding 1 to CO and CH3OH

1 CO + 2 H2 → 1 CH3OH

So the ratio of CO, H2 and CH3OH is 1:2:1

That means: 1 mole of CO will react with 2 moles of H2 to form 1 moles of CH3OH

With 5 moles of CO and 2.3 moles of H2, there are more CO than H2. So H2 is the limiting factor.

Going with the 2:1 ration, there will be 2.3/2 = 1.15 moles of CH3OH produced.

According to  the law of conservation of mass, if 5 moles of carbon monoxide react with 2.3 moles of hydrogen gas 7.3 moles of methanol can be produced.

According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.

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Answer:

Without the respiratory system your blood would be useless. The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body

Explanation:

Answer:

1- Environmental Value System or EVS is a worldview that molds the way both individuals and the societies they form perceive and therefore evaluate environmental concerns.

2-Entropy/ the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work.

3-Equilibrium/a state of balance between opposing forces or actions that is either static

4-Feedback/a return of information about a result or the returned portion of a process.

5-Feedback,negative/ is a self-regulatory system in which it feeds back to the input a part of a system's output so as to reverse the direction of change of the output.

6-Feedback,positive/ is the amplification of a body's response to a stimulus.

7-Gaia/ all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system

8-Model/a physical and/or mathematical and/or conceptual representation of a system of ideas, events or processes.

The LD50 (Lethal Dose 50) is a measure used in toxicology to determine the lethal dose of a substance that would cause death in 50% of the test population.

However, it is important to note that conducting experiments to determine the LD50 of a substance on humans is unethical and illegal. The LD50 values are typically determined through animal testing, usually on rodents such as rats or mice.To calculate the amount of a substance that would harm a person of a certain weight, various factors need to be considered, including the toxicity of the substance and the individual's weight. In toxicology, a commonly used measure is the oral median lethal dose (LD50) expressed as milligrams per kilogram of body weight (mg/kg).To estimate the harmful dose for an individual of a certain weight, you would need to know the LD50 value of the substance and apply it to the weight of the person. The calculation involves multiplying the LD50 value by the person's weight in kilograms. However, it is crucial to emphasize that estimating harmful doses for humans based on animal LD50 values alone can be inaccurate and potentially dangerous.

It is essential to consult professionals in toxicology or poison control centers to obtain accurate information regarding the toxicity of a substance and its potential effects on human health.

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Answer:

To draw a Lewis structure for a covalent compound, begin by calculating A, the available electrons, and N, the needed electrons.

What is N for silicon tetrachloride, SiCl4?

Explanation:

A covalent compound is formed by the mutual sharing of electrons between two atoms.

According to Lewis octet theory, every atom wants to attain eight electrons around it.

For the given molecule SiCl4

Silicon has four valence electrons.

To attain the nearest inert gas configuration it requires four more electrons.

Each chlorine atom shares an electron and thus silicon attains eight electrons in its valence shell.

The Chlorine atom has seven valence electrons.

To get eight electrons in its valence shell it needs one more electron.

That is shared by the silicon atom.

Thus both Si and Cl attain eight valence electrons by sharing electrons and for the covalent bond.

N value for Si is --- 4.

A the available electrons for Si is ---- 4.

The available electrons for Si 4 and the needed electrons are also 4. A covalent compound is formed by the equal sharing of electrons between two atoms.  

A covalent compound is formed by the equal sharing of electrons between two atoms.  

According to Lewis octet theory, every atom wants to attain eight electrons in the shell.  

For the given molecule \(\bold {SiCl_4}\)  

Thus both Si and Cl attain eight valence electrons by sharing electrons and for the covalent bond.  

Therefore,  the available electrons for Si 4 and the needed electrons are also 4.

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The new volume of the balloon will be determined by the Ideal Gas Law.

The Ideal Gas Law is a mathematical equation used to describe the behavior of an ideal gas under a given set of conditions. It states that, at a constant temperature and pressure, the pressure, volume and amount of gas present are all directly proportional.

This law states that the product of the pressure, volume, and temperature of a gas is a constant.
Since the pressure of the balloon remains constant, the new volume is inversely proportional to the temperature.
Therefore, the new volume can be calculated by dividing the original volume (13.5 liters) by the ratio of the original temperature (248 K) to the new temperature (324 K),
which is 248/324 = 0.76.
The new volume of the balloon is then 13.5 liters / 0.76 = 17.76 liters.

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The name of the process by which glucose is regenerated from lactate is called Cori cycle.

Cori cycle is the metabolic pathway in which lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is metabolized back to lactate.

This process was named after its discoverers as follows; Carl Ferdinand Cori and Gerty Cori.

The Cori cycle is a way to bring energy to the muscles during intense workouts and other times of lower oxygen levels in the body.

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Due of the weak intermolecular interactions, it has a high melting point.

A force that attracts the protons or positive parts of one molecule to the electrons or negative parts of another molecule is known as an intermolecular force. A substance's various physical and chemical properties are influenced by this force. The strength of an object's intermolecular forces determines its boiling point; the higher the intermolecular forces, the higher the boiling point.

We can compare the intermolecular forces between different substances by comparing their boiling points. This is so that these intermolecular interactions can be broken and the liquid can be transformed into vapour using the heat that the substance absorbs at its boiling point.

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The mass of ZnCl2 is  52.4 g.

The mass of NH3 is  12.24 g

We know that;

Number of moles of Zn = 25 g/65 g/mol

= 0.385 mole

If 1 mole of Zn produces 1 mole of ZnCl2

Then 0.385 mole of ZnCl2 is produced

Mass of the ZnCl2 produced =  0.385 mole * 136 g/mol

= 52.4 g

2) Number of moles of N2 = 10g/28 g/mol = 0.36 moles

Number of moles of H2 = 60 g/ 2g/mol = 30 moles

If 1 mole of N2 reacts with 3 moles of H2

0.36 moles of N2 reacts with 0.36 * 3/1

= 1.08 moles

Hence N2 is the limiting reactant

I mole of N2 produces 2 moles of NH3

0.36 moles of N2 will produce 0.36 * 2/1

= 0.72 moles

Mass of NH3 = 0.72 moles * 17 g/mol

= 12.24 g

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Silver is most likely the best conductor of heat according to the periodic table.

The most electrically conductive component is silver, taken after by copper and gold. Silver too has the most elevated warm conductivity of any component and the most noteworthy light reflectance.

The components can be classified as metals, nonmetals, or metalloids. The most electrically conductive component is silver, taken after by copper and gold. Silver too has the most elevated warm conductivity of any component and the most noteworthy light reflectance.

As to why silver is the most excellent conductor, the reply is that its electrons are more liberated to move than those of the other components.

This has got to do with its valence and gem structure. Most metals conduct power. Other components with tall electrical conductivity, are aluminum, zinc, nickel, press, and platinum. Brass and bronze are electrically conductive amalgams, instead of components.

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a. Probability (X = 3) = 0.180

b. Probability(X < 3) = 0.676

c. Probability(X >= 3) =  0.324

d. Probability (X >= 1) =  0.865

e. Probability (X >= 5) =  0.0525

(a)  we find the Probability of exactly three insect fragments in a 4-gram sample as :

λ = 0.5 * 4 = 2

P(X = 3) = (e^(-2) * 2^3) / 3!

P(X = 3) =  0.180

(b) Probability of fewer than three insect fragments in a 4-gram sample:

P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)

P(X < 3) = e^(-2) + (e^(-2) * 2) + (e^(-2) * 2^2)

P(X < 3) = 0.676

(c) Probability of at least three insect fragments in a 4-gram sample:

P(X >= 3) = 1 - P(X < 3)

P(X >= 3) ≈ 1 - 0.676

P(X >= 3) =  0.324

(d) Probability of at least one insect fragment in a 4-gram sample:

P(X >= 1) = 1 - P(X = 0)

P(X >= 1) ≈ 1 - e^(-2)

P(X >= 1) =  0.865

e. The Unusualness of containing five or more insect fragments is found as :

P(X >= 5) = 1 - (P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4))

P(X >= 5) = 1 - (0.1353 + 0.2707 + 0.2707 + 0.1805 + 0.0903)

P(X >= 5) ≈ 1 - 0.9475

P(X >= 5) =  0.0525

In conclusion, the probability of a 4-gram sample of this supply of peanut butter containing five or more insect fragments is found to be 0.0525.

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The mass number of an atom of potassium that has 20 neutrons is option C. 39

Mass number-

Mass number is the total number of protons and neutrons in the nucleus of an atom is called the mass number. It is represented by the symbol A. In other words, mass number refers to the sum of the number of protons and neutrons in the nucleus of an atom.

Atom-

Atoms are tiny particles that make up everything in the world. Everything in the world is made up of tiny particles known as atoms. An atom is the basic unit of matter. The term "atom" comes from the Greek word atomos, which means indivisible.

The basic building blocks of all matter are atoms, which are made up of three types of particles: protons, neutrons, and electrons.

In a neutral atom, the number of electrons is equal to the number of protons, thus the overall charge on the atom is zero. However, the mass number of the atom is equal to the sum of the number of protons and neutrons.

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Answer and Explanation:

In H2O molecules, due to formation of intermolecular hydrogen bonds, there is molecular association. Large amount of energy is required to break these intermolecular hydrogen bonds. Intermolecular hydrogen bonding is not possible in H2S. Hence, its boiling point is lower and is a gas.

Answer: sodium

Explanation: Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color of flame they produce. For example, copper produces a blue flame, lithium and strontium a red flame, calcium an orange flame, sodium a yellow flame, and barium a green flame.

Based on the flame test, the gaseous element which is present in street lights is sodium.

Spectrum is a table or a chart in which intensity of the emitted lights are showing over a range of species.

Each element show different color of spectrum in the emission process, whenever excited element emitted enegy then released energy is shown in the form of color spectrum. In traffic lights sodium lamps are present which in the presence of heat gets excited and changes to the gas form and emitted yellow color light.

Hence sodium gaseous element is present in street lights.

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A 2 g sample of \(CoCl_{2} .xH_{2} O\) is dried in the oven when the anhydrous salt is removed from the oven its mass is 1.565 g then the value of x is 0.024  .

Calculation ,

mass =  2 g ( given )

molar mass = 134.45 + x × 18

After dehydration or when the anhydrous salt is removed from the oven  mass remain = 1.565 g

Molar mass = 134.45

Thus mass of \(H_{2} O\) = 2 g - 1.565 g = 0.435 g

Number of moles of water =  0.435 g / 18  = 0.024 moles

Therefore value of x = 0.024

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The option that shows that the kinetic-molecular explanations of this principle is NOT correct is option B: The number of molecular impacts per unit area decreases at a higher temperature.

The assumption that matter is made up of microscopic particles that are always in motion forms the foundation of the kinetic-molecular theory, which explains the states of matter.

Therefore, based on the use of observable characteristics as well as the use of behaviors of solids, liquids, as well as gases are known to be explained by kinetic-molecular theory.

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Answer:

B

Explanation:

Answer:

first theres the poliution  one of the biggest things thats starts global warming then theres recycle and non recycle because people mix there trash up when their not suppossed to.

Explanation:

To prepare 35 mL of a 0.60 M solution of FeSO4, you would need 0.735 grams of FeSO4.

To calculate the number of grams of FeSO4 needed, we can use the formula:

Mass (g) = Volume (L) x Concentration (mol/L) x Molar mass (g/mol)

First, we need to convert the volume from milliliters (mL) to liters (L) by dividing by 1000:

35 mL ÷ 1000 = 0.035 L

Next, we can substitute the values into the formula:

Mass (g) = 0.035 L x 0.60 mol/L x molar mass of FeSO4 (g/mol)

The molar mass of FeSO4 can be calculated by summing the atomic masses of its constituent elements:

Molar mass of FeSO4 = (atomic mass of Fe) + (atomic mass of S) + 4 x (atomic mass of O)

= (55.845 g/mol) + (32.06 g/mol) + 4 x (16.00 g/mol)

= 151.908 g/mol

Substituting the molar mass into the formula:

Mass (g) = 0.035 L x 0.60 mol/L x 151.908 g/mol

Mass (g) = 0.735 grams

Therefore, you would need 0.735 grams of FeSO4 to prepare 35 mL of a 0.60 M solution.

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Cs has the lowest first-ionization energy.

What is first-ionization energy?

In order to create one mole of gaseous ions with a charge of 1+ from one mole of neutral gaseous atoms, the first ionization energy must be used to remove the most loosely held electron. In terms of symbols, this is simpler to understand. It is the amount of energy required to make this transformation for each mole of X.

What is Ionization energy?

The ionization energy assesses an element's capacity to engage in chemical reactions that require the donation of electrons or the production of ions. It frequently has to do with the kind of chemical bonds that are formed between the constituents of the compounds that they produce. See also electron affinity and binding energy.

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The value of the specific rate constant, k, in the gas phase reaction A+B ® C would be affected by increasing the temperature. Therefore, the correct answer is option (a) "increasing the temperature".

The specific rate constant, k, is a proportionality constant that relates the rate of a reaction to the concentrations of the reactants. It is a measure of the intrinsic reactivity of the reactants and is affected by factors such as temperature and the presence of a catalyst. Changing the concentration of A or B would not affect the value of k, as it is a constant for a given reaction at a given temperature.

However, increasing the temperature would increase the value of k, as the reaction rate generally increases with temperature. This is because an increase in temperature increases the kinetic energy of the molecules, leading to more frequent and energetic collisions between the reactants, and therefore a faster reaction rate.

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Answer:

B and C

Explanation:

is it multiple choice question??

Van der Waals forces are the interaction between the molecules and the atoms. It increases with an increase in the molecular size and the number of electrons. Thus, options B and C are correct.

Van der Waals forces are the weak forces of attraction and repulsion present between the atoms and the molecules of the compounds. They are also called London Dispersion Forces and dipole-dipole forces.

An increase in the number of electrons and size of the molecule increases the surface area and the electron cloud which in turn, increases the Van der Waals force.

The intermolecular force increases as in large atoms or molecules the valence are held loosely as they are far from the nucleus or the center of the atom.

Therefore, the size and the electron increase the Van der Waals force.

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Answer:

c tarnishes in air

Explanation:

After silver has been exposed to air that contains sulphur gases, discoloration would occur. there would be darkening that is caused by the reaction with gases.When any silver object tarnishes, it brings about a disfiguring of that object. Hydrogen sulphide would be needed for this to happen. silver sulphide is black and a if a thin layer should form on any surface, it ill darken it. This  is what we refer to as tarnishing.

Answer:

c

Explanation:

it tarnishes in air

The conjugate base of the alkyne can be shown as

\(CH_{3} CH_{2} CH_{2} C\)≡\(C^-\)

A hydrocarbon with a triple bond between carbon atoms is an alkyne. In order to obtain a stable electron configuration, an alkyne that has lost a proton gains an additional electron to form the equivalent alkynide ion.

When an akyne loses a proton, the corresponding alkynide ions can form. The triple bond is still present in the alkynide ion, which also has a negative charge on the carbon atom where the proton was taken out.

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