The half-life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later

Answer:

tells you by mass what percent of each element is present in a compound.

Explanation:

When a beaker of ethanoic acid is placed in the refrigerator and mix it with sodium carbonate, its temperature drops down and endothermic reaction take place.

[tex]2CH_{3} COOH + NaCO_{3}[/tex]    ⇒ [tex]CH_{3}COONa + NaHCO_{3}[/tex]

This chemical reaction is a reversible reaction.

Ethanoic acid and sodium carbonate combine to form an endothermic reaction that results in fizzing as carbon dioxide is released and heat is lost to the environment, making the reaction vessel feel chilly to the touch.

The difference between adding sodium carbonate to the solution and refrigerating ethanoic acid is that no new substance is created in the former. When the substance is taken out of the refrigerator, it is still ethanoic acid. New chemicals are created in the latter scenario. Because of a chemical process, the material is no longer ethanoic acid.

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An experimental group and a control group are both included in a controlled experiment. At least one of the two groups—the group that is not subjected to the experimental treatment—is present in a controlled experiment.    

In controlled experiment, the researcher wants to determine how one or more variables affects on something. Since many different variables affecting the results, and most of them are not of interest to the researcher, and they will kept under control. They must remain constant. There must be at least of two groups. One of them is control group, and the other one is experimental group.  

During experiment, a researcher compares between two groups. Both are composed of individuals which is coming from same population, so they are very identical in all the aspects except for independent variables that the researcher changes in to the  experimental group and they observe that how they will affect the individuals.  Control group is used to identify any of the other factors influencing the results which is obtained in the study, apart from the modified variables of the treatment. Independent variable keeps constant in control group.  

The experimental group receives the treatment. The researcher voluntarily modifies the independent variable's values to see how it impacts the subjects. There can be several experimental groups.

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During glycolysis, each G3P produces two ATP, for a total of four ATP per glucose molecule.

The metabolic mechanism that transforms glucose to pyruvate is known as glycolysis. This free energy is utilized to create the high-energy molecules adenosine triphosphate and reduced nicotinamide adenine dinucleotide. Glycolysis is a series of 10 enzyme-catalyzed processes. The initial stage in the breakdown of glucose to extract energy for cellular metabolism is glycolysis. Glycolysis is divided into two phases: energy-requiring and energy-releasing. Glycolysis is the process of breaking down glucose to create energy. It generates two pyruvate molecules, ATP, NADH, and water. The process occurs in a cell's cytoplasm and does not require oxygen. It can be found in aerobic and anaerobic organisms.

Here,

Each G3P produces two ATP during glycolysis, for a total of four ATP per glucose molecule.

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There is no heat exchange with the environment since the calorimeter is insulated. This may be demonstrated by saying: Since the calorimeter is a fixed unit, it follows that its heat capacity likewise has a fixed value.

Calorimeters are the tools used to measure the amount of heat. The definitions of heat and temperature, the quantity of heat absorbed to raise a body's temperature, the distinction between heat and temperature, and specific heat capacity are among the fundamental ideas presented in this chapter. A chemical reaction's associated thermal energy change is what causes a calorimeter's temperature to fluctuate. If the calorimeter absorbs heat (q calorimeter > 0) and its temperature rises, the reaction is producing heat (q rxn 0).

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The isotope that when bombarded with nitrogen-15 yields the artificial isotope dubnium-260 plus 4 neutrons is californium-249.

Californium-249 is a heavy element and when bombarded with nitrogen-15, which is a light element, undergoes a nuclear reaction known as a "cold" fusion reaction. This reaction results in the formation of the artificial isotope dubnium-260, which has a higher atomic number than the starting element and the release of 4 neutrons.This process is known as a Nuclear Transmutation, which is a process in which one element is converted into another element by bombarding it with a beam of particles such as protons, neutrons, or other ions.

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The solubility of AgCN in a solution containing 1.0M H Ksp of AgCN is 2.2e-12 Ka of HCN is 6.2e-10 is 5.9 x 10^-2M.

Given concentration of H+ (M) = 1.0M

Ksp of AgCN = 2.2e-12

Ka  of HCN = 6.2e-10

AgCN ⇋ Ag+ +CN− ................Ksp

CN − + H+ ⇋ HCN................... 1/Ka​

AgCN + H+ ⇋ HCN + Ag+ ...................Ksp/Ka = K0

K0 = 2.2e-12/6.2e-10 = 0.0035 = 35 x 10-4

At Equilibrium:   AgCN + H+ ⇋ HCN + Ag+

Let the moles of [Ag+] = x

So the number of moles of [HCN] = x

K0 = [Ag+] [HCN] / [H+]

35 x 10-4 = x^2/1

x = 5.9 x 10^-2M

Hence the molar solubility of AgCN in buffer solution is 5.9 x 10^-2M.

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​

The two quantities in this module for which we will develop unit factors to do dimensional analysis with chemical substances are mass (m) and volume (V).

To calculate the unit factor, we need to divide the unit of the desired quantity by the unit of the given quantity. For example, to convert from mass to volume, the unit factor is V/m.

This unit factor can then be used to convert mass to volume or vice versa. Dimensional analysis helps us to determine the proper units for a given equation and to convert from one unit to another.

It also allows us to compare different units of measurement and to check that the units in both sides of an equation match. This is especially useful in chemical calculations, where it is important to ensure the correct units are used.

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Answer: 4 ATP molecules is produced in the glycolysis of 2 glucose molecules

The first stage of most carbohydrate catabolism, which is described as the breakdown of larger molecules into smaller ones, is glycolysis, which is a part of cellular respiration. Two Greek words that mean "to break down anything sweet" are the source of the word glycolysis. Two molecules of ATP are created during the breakdown of glucose and formation of pyruvate during glycolysis.

Explanation:

2 ATP are produced.

For every glucose molecule, meaning that for every 2 glucose molecules, 4 ATP will be created.

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14 mean in C14 is C14 has atomic mass of 14.

The radioactive carbon isotope with the longest half-life, carbon-14, whose decay enables precise dating of archaeological artifacts. Six protons and eight neutrons make up the carbon-14 nucleus, giving it an atomic mass of 14. Additionally, the isotope is employed as a tracer to monitor specific carbon atoms as they undergo chemical or biological changes.

The 14 in C14  represents the number of neutrons and protons in the nucleus of that atom or we can called it atomic mass. Carbon-14: with 6 protons and 8 neutrons, and an atomic mass of 14,

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Distance can be measured by centimeters (cm) and kilometers (km).

Distance is defined as the total movement of an object without any regard to the direction. Distance is the length of the route between the two points.

SI unit of distance is the meter (m). Short distances may be measured in the centimeters (cm), and the long distances may be measured in kilometers (km).  For example: Measure the distance from the bottom to the top of a sheet of paper in centimeters and the distance from your house to your school. Maps are also used to measure the the distance.

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The average molecular velocity of the molecules will decrease as the reaction goes to completion at a constant temperature.

What is Molecular velocity?

Molecular velocity is the average speed of molecules in a sample of matter. It is determined by the temperature of the sample, with higher temperatures resulting in higher molecular velocities.

This is because the reaction produces a single product, meaning that the number of molecules in the reaction vessel is decreasing as the reaction goes to completion. As the number of molecules decreases, the average molecular velocity of the molecules decreases as well.

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Answer:

Therefore, there are 4.47 moles of propane present at STP in a volume of 65.0 L

Explanation:

First, we need to calculate the number of moles of propane present at STP. At STP, the temperature is 273 K and the pressure is 1 atm.

Using the Ideal Gas Law, we can calculate the number of moles of propane present in the given volume.

PV = nRT

n = 4.47 mol

Therefore, there are 4.47 moles of propane present at STP in a volume of 65.0 L

By beta, tungsten 188 decays. The mechanism through which an insecure atomic structure is produced is known as radioactive decay.

The process through which highly unstable molecular nucleus loses its energy through radiation is described as radioactive decay, also characterized as nuclear decay, radiography, radioactivity breakdown, or nuclear disintegration. A substance that has unstable nuclei is regarded as radioactive. For a large variety of human activities, radioactive decay is crucial.

Alpha, beta, and/or gamma rays are all types of ionizing radiation that are released when radioactive atoms decay. Because the energy is powerful enough to dislodge firmly coupled electrons from just an atom's orbit, it is known as ionizing radiation. As a result, the atom develops into a charged ion.

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The law that demonstrates this observation is the law of definite proportions.

Law of definite proportion states that a given chemical compound continually incorporates its element factors in constant ratio (with the aid of using mass) and does now no longer rely on its supply and technique of preparation. Law of Definite Proportions states that during a given kind of chemical substance, the factors are continually blended withinside the identical proportions with the aid of using mass. The Law of Definite Proportions applies while factors are reacted collectively to shape the identical product. Such as , a sample of an unknown substance contains 24. 0 grams of carbon and 2. 0 grams of hydrogen.

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He is not falling nor about to fall which means he’s perfectly balanced. So this means the force in the photo and friction in this photo is in a balanced condition, balancing the boy.

In the given picture, the applied force and the force of friction are balanced. if two forces act in the direction to make the object in a balanced state.

If the forces are in a balanced state it does not change the motion of the object, and if it is in an unbalanced state, it causes to change in the state of the motion.

Therefore, the force of friction and the gravitational force are balanced is the correct option.

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The given question is incomplete, so the complete question image is attached in the image below.

Wave nature of matter is responsible for interference pattern being exhibited by electrons.

Shortly after de Broglie proposed the wave nature of matter, two scientists at Bell Labs, C.J. showed experimentally that electrons can exhibit wave-like behavior. The wave-like motion of electrons is mathematically described by the so-called Bloch wave function. Named after his 20th-century physicist Felix Bloch, who first described the behavior of electrons in crystalline solids, these wavefunctions are complex. That is, it has both real and imaginary components.

These waves are called matter waves because electrons are a type of matter. Here,we relate the quantitative features of matter waves to familiar and measurable physical quantities such as energy, mass, and momentum.

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Answer:

4g of hydrogen

Explanation:

4g of hydrogen (molar mass 2) corresponds to 2 moles of molecules or 4N number of atoms where N is the Avogadro's number (6.023×10

23)

No, because  every M&M's is identical.

M&M's contain the same amount of protons, M&M's are the same hue. In other words, the size represents the various neutron counts.

Atoms of the same chemical element called isotopes each have a distinct mass number.

While isotopes can vary in mass, they never do so in atomic number (the amount of protons). You will use M&Ms to represent atoms because we are unable to see them. These objectives are use in M&Ms to determine the average atomic mass and to observe how different isotopes are.

In this the number show how many M&M's of that color and size are packed into that bags.

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Answer:

Explanation:

A proton has a relative mass of 1. A neutron has a relative mass of 1. An electron has a relative mass of 1/1840. (accept 0)

An atom of phosphorus, which has a proton mass number of 31 has 15 protons, 15 electrons, and 16 neutrons.

Atom- The fundamental units of matter are atoms. They have a single nucleus, which is surrounded by a small number of protons and electrons.

Element- A species of atom known as an element is one that cannot decompose further. They only contain one kind of atom with the same quantity of protons.

Role of Neutron-

Neutron's charge is neutral. The element's mass is made up of protons and neutrons.

The neutrons' main function in an atom's nucleus is to contribute to the nuclear glue or binding energy that binds the nucleus itself together. Remember that protons and neutrons make up an atomic nucleus.

Positively charged protons don't get along with one another.

Neutrons are added to the structure to make up for the so-called mass deficit in order to counteract the protons' attractive forces.

In order to keep the nucleus together, the nucleons—the protons and neutrons in a nucleus—lose a little bit of mass that is transformed into binding energy.

Proton has  relative mass of 1 while   neutron has  relative mass of 1. While that of an electron has  relative mass of 1/1840.In phosphorous there are 15 electrons , protons and 16 neutrons.Atoms of same type combine to form element.Neutrons contribute to mass of atom hence change in number will make atom unstable.

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

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Atomic Number of the periodic table is needed to determine why KCl tastes like NaCl.

What is the Periodic Table?

The Periodic Table is a tabular arrangement of the chemical elements organized by atomic number, electron configuration, and recurring chemical properties. It is one of the most important tools in chemistry, providing a useful framework to classify, systematize, and predict the properties of elements.

Atomic numbers are used to identify each element in the periodic table, and they are also used to determine the number of protons in the nucleus of an atom. The number of protons in an atom determines its chemical properties, and the similarity in the number of protons between two elements can explain why they have similar properties. In this case, the similarity in the atomic number of potassium (K, atomic number 19) and sodium (Na, atomic number 11) explains why the salts of both elements, potassium chloride (KCl) and sodium chloride (NaCl), taste the same.

Hence, Option D is correct.

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An extremely efficient enzyme has a small KM and a large kcat.

The conversion rate at the lowest substrate concentration is measured in kcat/km. This interpretation is accurate. kcat/Km is a good indicator of an enzyme's effectiveness since it takes into account both the enzyme's maximum rate, kcat, and its affinity for its substrate (Km).The turnover number, or the number of molecules that may be created per second per active site, of an enzyme is provided by the formula k c a t / kM.Because the substrate concentration is almost usually much greater than the Km, in many situations, enzymes are only better when they have a larger kcat. It seems disingenuous to me to use the ratio when this is plainly the case, yet it still happens much too frequently. It could serve as a useful benchmark when compared to enzymes in particular situations.

complete question:An extremely efficient enzyme has a _____ KM and a _____ kcat.

A) small; small

B) small; large

C) large; large

D) large; small

E) kcat and KM do nothing to predict the efficiency of an enzyme

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0.5 moles of carbon weigh 6.0055 grams.

One of the chemical elements is carbon. The letter C stands for carbon, and the letter g stands for grams. As a result, 0.5 moles of carbon per gram is equivalent to 0.5 moles of carbon per gram, 0.5 moles of carbon per gram, and 0.5 moles of C per gram.

Carbon has a 12.011 atomic mass. Thus, one mole of carbon has a mass of 12.011 grams (12.011 g/mol). We multiply 0.5 moles of carbon by 12.011 to get grams, and vice versa.

no. of Grams = Moles of Carbon x 12.011

                     =0.5 × 12.011 = 6.0055

0.5 moles of carbon equal 6.0055 grams.

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The complete question is

How many grams is 0.5 moles of carbon

xenon fluorides are known to undergo hydrolysis to give the hydrohalic acid and the rare gas oxide similar to the following equation: XeF6 + 3H2O -> XeO3 + 6HF.

A noble gas compound with the formula XeF6 is xenon hexafluoride. It is one of xenon's three binary fluorides, along with XeF2 and XeF4. All known are exergonic and stable at normal temperatures. The series' strongest fluorinating agent is XeF6.Water's chemical formula is H2O, which means that each of its molecules consists of two hydrogen atoms and one oxygen atom. In its +6 oxidation state, xenon can form the unstable chemical xenon trioxide(XeO3). It is an extremely potent oxidizing agent that slowly releases oxygen from water, a process that is sped up by sunshine. When it comes into touch with organic materials, it explodes dangerously. It emits xenon and oxygen gas when it explodes.

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The dominant phenotype for sheep color is wool because it is the most common color seen in sheep.

What do you mean by Phenotype?

Phenotype is the physical, biochemical, and physiological characteristics of an organism, as determined by both genetic makeup and environmental influences. It is the physical expression of an organism's genes, and can be seen in its morphology, development, and behavior.

Wool is usually white or off-white in color and is the result of a dominant gene. The recessive phenotype for sheep color is non-wool, which is usually a darker color, such as black, brown, or gray. This is the result of a recessive gene and is less common than the dominant gene.

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At a pressure of 12.4 atm and a temperature of 850 c, 8.2 liters of water can be created from 55 grams of oxygen gas and an excess of hydrogen.

first, we need the no.of moles of O2 = mass/molar mass of O2

                                                            = 55 g / 32 g/mol

                                                            = 1.72 mol

from the balanced equation of the reaction:

2H2 (g) + O2(g) → 2H2O(g)

we can see that the molar ratio between O2: H2O = 1: 2

So we can get the no.of moles of H2O = 2 * moles of O2

                                                                 = 2 * 1.72 mol

                                                                 = 3.44 mol

So by substitution by this value in the ideal gas formula:

PV = nRT

when P = 12.4 atm  & n H2O = 3.44 mol & R= 0.0821 & T = 85 + 273=358K

12.4 atm *V = 3.44 * 0.0821 * 358 = 8.15 L

∴ V ≈ 8.2 L

In the physical sciences, pressure is defined as the perpendicular force per unit area or stress at a point within a confined fluid. The pressure exerted on a floor by a 42-pound box with a bottom area of 84 square inches is equal to the force divided by the area over which it is exerted, or one-half pound per square inch.

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The reactant is iron (Fe) and the oxidizing agent is oxygen (O). This reaction results in the the formation of a compound known as iron oxide (Fe2O3), which is commonly referred to as rust. The reaction can be written as:

Fe + O2 --> Fe2O3

The oxidation process involves the loss of electrons from the Fe atoms, as oxygen gains electrons and is reduced. The electrons are transferred from the iron to the oxygen, resulting in the formation of iron oxide, which is an insoluble solid.

An oxidation-reduction reaction, or redox reaction, is a reaction in which there is a transfer of electrons between chemical species (the atoms, ions, or molecules involved in the reaction).

The reaction can be written as: [tex]\bold{Fe + O2 \Rightarrow Fe_2O_3}[/tex]

In order to produce a nucleotide, the combinations 11, 12, and 13 may be combined.

The basic unit of DNA and RNA are nucleotides. Genetic material is present in them. Since many biological reactions involving enzymes require coenzymes, nucleotides serve in this capacity. ATP serves as the body's energy storage system.

A phosphodiester bond forms when the 5' phosphate group of one nucleotide and the 3'-OH group of another nucleotide come together during the incorporation of nucleotides into DNA (see below). Phosphate-sugar-phosphate-sugar-phosphate forms the "backbone" of each DNA strand in this way.

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