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

The definition of the meter in biology is that the meter scale is used to measure the length. it is first unit of the international system of the units.

The meter is the first unit of the length in the international system of the units. currently the definition of the meter is : The meter can be defined as the length of the path that is travelled by the light in the vacuum during the time interval of 1 / 2999792458 second. The symbol of the meter is m.

The meter scale is used to measure the length or the distance between the two points.

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Being a highly chemically reactive metal having seven valence electrons and even a high attraction for electrons, bromine reacts quickly as well as violently with alkali metals, therefore is rarely found in nature pure.

Despite being a potent oxidizer, it is difficult to break down under typical circumstances. Fluorine was the strongest active halogen, followed by chlorine, bromine, as well as iodine.

Since bromine has a higher atomic radius over chlorine, it is much less reactive. Compared to chlorine, bromine does not hold electrons as tightly. This is supported by the fact that chlorine contains fewer electron shells, which causes the electrons to connect nearer to the nucleus.

Due to its lower reactivity, the bromine radical is so much more selective for such 2° radical. Cl• is much less picky and less selective since it is less stable as well as more reactive.

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The price of the wax from the U.S. supplier in €/kg would be: €25.53 / 2.20 lb = €11.67/kg.

The price of the wax from the German supplier in $/lb would be $11.90 / 0.76 = $15.68/lb.

This price is calculated by taking the cost of the wax in US dollars and converting it to Euros using the current exchange rate of $1 = €0.76.

This price is calculated by taking the cost of the wax in Euros and converting it to US dollars using the current exchange rate of $1 = €0.76. It's important to note that the price of the wax from the German supplier is higher than the price from the US supplier when converted to dollars per pound.

This is because the price per kg is lower but the conversion to pound makes it higher.

The price of the wax from the U.S. supplier in €/kg would be: €25.53 / 2.20 lb = €11.67/kg.

The price of the wax from the German supplier in $/lb would be $11.90 / 0.76 = $15.68/lb.

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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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If the actual yield and percent yield are 51.4g and 77.0%, respectively, calculate the theoretical yield. We predicted a theoretical yield of 13 grams for the reaction of Na with Cl2.

Yield is determined by dividing the principal amount by the net realized return. Gains and returns on stock investments, for instance, can take one of two kinds. On the basis of the chemical equation's stoichiometry, theoretical yield is computed. Experimental data are used to determine the real yield. Calculating the ratio of actual yield to theoretical yield yields the percent yield. The % ratio of the theoretical yield to the actual yield is known as the percent yield. It is calculated as the theoretical yield multiplied by 100% divided by the experimental yield.

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The amount, in grams of Pb that would be required to make 119 g of [tex]H_2O[/tex] will be 685.17 grams.

The balanced equation of the reaction would be as follows:

[tex]Pb+PbO_2+2H_2SO_4--- > 2PbSO_4+2H_2O[/tex]

The mole ratio of Pb to [tex]H_2O[/tex] is 1:2.

Recall that, mole = mass/molar mass.

Molar mass of [tex]H_2O[/tex] = 18 g/mol

Mole of 119 g of [tex]H_2O[/tex] = 119/18 = 6.61 mol

From the established mole ratio, the equivalent mole of Pb that would be required will be:

1/2 x 6.61 = 3.31 mol

Mass = mole x molar mass

The molar mass of Pb is 207 g/mol

Mass of 3.31 mol Pb = 3.31 x 207

                                  = 685.17 grams

In other words, the amount of Pb that would be required to make 119 g of [tex]H_2O[/tex] according to the illustrated reaction will be 685.17 grams.

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A chemist reported that 100 gallons of a gas were available in a laboratory, The property of the gas did the chemist report is volume option - D is correct answer.

The space occupied by a three-dimensional object is measured using the scalar quantity known as volume. The volume of a liquid or gas is calculated using the container's capacity as the unit of measurement.

A state of matter known as gas lacks a consistent shape and a set volume. They are the least dense and have the most space between their moles.

A gallon is a unit of volume that is used in the American metric system. The volume of gas equals the sum of the moles of gas in the container, which contains 100 gallons of gas.

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Elements 'X', 'Y' and 'Z' have these atomic radii, in nanometers. X 0.072 nm Y 0.099 nm Z 0.111 nm. When atomic radii are correctly arranged,  the elements appears as z , y and then x across the period.

The atomic radii decreases across the period as we move from the left to right in the periodic table. the atomic radii will decreases as we move from the left to the right in the periodic table because in the period from the left to right the number of the electron will increases.

Thus, the order of the given elements arranged in the period in the periodic table as first z , then y and then x.

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She changed the mask chemically. Burning of the substance with acid is a chemical change.

A new substance with new qualities is created during burning, which is a chemical alteration that cannot be undone. A chemical change is the transformation of one substance into another, the emergence of new compounds with distinct properties, or any combination of these. It happens when two substances mix to create a new material. Baking soda and vinegar producing carbon dioxide, iron rusting, and wood burning are a few examples of chemical changes. The metabolization of food and the production of amylase from the combining of sugar and saliva are only two examples of the many chemical processes that the body produces.

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Nitrate NO 2 It is inappropriate to use one of the following ions' names and formulas.

Herbicides, explosives, defoliants, paper, leather, dyes, matches, and inks are all made from it. It's also used to make cosmetics and medications. An inorganic salt of sodium with the counter-ion chlorate is known as sodium chlorate. It serves as both a herbicide and an oxidizing agent for bleaching paper.

Chlorate, an anion, can enter drinking water through a number of different causes, such as the use of hypochlorite or chlorine dioxide as disinfectants, the oxidation of hypochlorite or chlorite by ozone, and pesticide runoff or paper mill discharges that contaminate the source water.

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Answer:

Water is a compound because it is made up of water molecules. There is no such thing as water atoms. Water molecules are made of hydrogen and oxygen atoms, in the definite proportion of two hydrogens for one oxygen.

Explanation:

The difference between a molecule and a compound is this:

A molecule consists of two or more atoms joined by a chemical bond.

A compound consists of two or more different atoms joined by chemical bonds.

Water (H2O) is both a molecule and a compound.

Hydrogen gas (H2) and oxygen gas (O2) are molecules but because the atoms of which they are made are not different, they do not qualify as compounds.

moles of HCl are reacting is [tex]135\times10^{-3}[/tex]

In the International System of Units, the mole is used to measure material quantity. The number of a substance's elementary entities that are present in an object or sample depends on the amount of that substance. A solute's molar concentration is used to represent how much of a solute there is per unit volume of a solution or how much of a chemical species there is in a solution.

Magnesium reacts with hydrochloric acid to generate a salt of magnesium chloride and release hydrogen gas.

Mg(s) +HCl(aq) [tex]\rightarrow[/tex] [tex]MgCl_{2}[/tex](aq)+[tex]H_{2}[/tex](g)

molarity =[tex]\frac{moles of solute}{volume of solution \:(l)}[/tex]

molarity of Mg is 3.0M volume of solution is 45ml

now, 3M=[tex]\frac{moles of solute}{45\times 10^{-3} \:(l)}[/tex]

moles of mg = 135 millimoles.

now according to the reaction by using stoichiometry

moles of Mg = moles of HCl

moles of HCl =135 millimoles =[tex]135\times10^{-3}[/tex]

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Option (c) is correct. K atom has the largest radius as the atomic size decreases from across the period and potassium is located in the start of period 3  in the periodic table.

According to the Periodic table, atomic size decreases when going from left to right across a period. Atomic size increases when going from top to bottom down a group. If you look at elements that are located in the same group, potassium will have a larger atomic radius when compared with sodium and  chlorine. Since potassium is located at the start of period 3, potassium will have a larger atomic radius and thus the largest atomic radius of the four given atoms. Atomic radii vary in a predictable way across the periodic table. From top to bottom in a group, orbitals corresponding to higher values of the principal quantum number (n) are being added, which are on average further away from the nucleus, thus causing the size of the atom to increase.

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The mole fraction of ethanol, C2H5OH is 0.076 that can be calculated by using the density of water.

The mole fraction of any solution is described because the ratio of the quantity of moles of that is present withinside the technique to the entire quantity of moles of all of the additives of the solution. Molarity on the other hand is the ratio of moles to the volume.

Molecular mass of ethanol = 46g

The molarity of the solution is 4.6 molal=4 moles in 1L solution

Molecular mass of water =18g

Density of water = 1kg/m3 = 1000g/L

So, mass of water in 1 l solution = 1000g

So moles = 1000/18 = 55.55 moles

Thus, mole fraction of ethanol= 4.6/(4.6+55.6) =0.076

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Nitrous acid HNO_2 would be more suitable for use in a solution buffered at pH = 7.0.The other ion needed to make the buffer would be the conjugate base of the acid, which in this case would be the nitrite ion NO_2^-.

A, The Ka value is an indication of the strength of an acid; the lower the Ka value, the weaker the acid. Therefore, the hypochlorous acid HClO has a weaker acidity than nitrous acid HNO_2 and would be less suitable for use in a solution buffered at pH = 7.0.

B, Buffers work by maintaining a certain pH by providing a source of a weak acid and its conjugate base. Therefore, the other ion needed to make the buffer is the conjugate base of the acid, which in this case is the nitrite ion NO_2^-.

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In a first-order breakdown reaction, 81.8% of the molecule takes 19.0 min to break down. A compound breaks down in 7.3 minutes by 33%. The human race started to scratch right away.

A means of climbing the food chain. People snatched what they needed from those who were unsuccessful in the same race without regard for anyone else (the producers and the rest of the consumers). First order in both surfactant and acid concentrations, decomposition is a dislocation process of reaction. The process is autocatalytic since acid is produced during the degradation. Reservoir rock, on the other hand, has a sizable absorbing impact.

x = (81.8*7.3)/33 x = 19.0 min

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To solve this we must be knowing each and every concept related to  landslides. Therefore, the given process describe the landslides process.

Slope collapses are essentially natural calamities that occur in a variety of locations across the world. Slope failures, often known as landslides, define a wide range of mechanisms that produce the outward or downward of slope-forming materials such as rock, soil, or landfills.

The down-slope movement of material on Earth is called a slope failure. It is the failure of the slope resulting in transport of debris downhill by sliding, rolling, falling, or slumping. This is an example of slope failure called landslides.

Therefore, the given process describe the landslides process.

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The reaction that has been shown in the table above is a double replacement reaction, and each compound has the same set of ions. Option D

Another word that we can use for reaction is what we call a chemical change. We know that a chemical change is the kind of change that will lead to the formation of a new product. It is an irreversible process as we can not be able to get back the reactants again.

We should note that there are various types of reactions. In a single  replacement reaction, you would notice that there is only one substance that reacts and causes a change while in the double replacement reaction, the anions that are in the compounds that underwent the reaction would just exchange anion partners and we would have two ionic products.

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The Sun is a close second in terms of object radii. It would be so spherical if shrunk to the size of a beach ball that the distance between its widest and narrowest diameters would be significantly smaller than the width of a human hair.

Our world is greatly influenced by the sun, which controls the weather, ocean currents, seasons, and climate as well as enabling plant life through photosynthesis. Life on Earth would not live without the heat and light provided by the sun.

Because they developed and collapsed under the force of their own gravity, the Sun and the majority of other big objects in space, including stars, planets, and large moons, are spherical. When our Solar System first formed, it was a massive, whirling cloud of gas and dust that gradually shrank due to gravity.

Thus, The Sun is a close second in terms of object radii.

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Thermal energy is transformed into kinetic energy that is, the energy of a moving object in this example, the moving piston by the engine. So, the sign of heat is negative and work done is negative.

A complicated device known as a combustion engine consumes fuel to produce thermal energy, which is subsequently used to drive tasks. In a car, the engine is responsible for generating the kinetic energy needed to turn the wheels. An internal combustion engine is the type of combustion engine used in automobiles. Internal-combustion engines are those found in gasoline or diesel-powered automobiles. Such an engine obtains its power from the heat produced during the combustion of the working fluids that have not yet reacted, the oxidizer-fuel mixture. As the heat is released to convert into the kinetic energy the sign of heat is negative and the sign of work done by the internal combustion of vehicles is negative.

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The given statement is true as in the radioactive decay results in significant mass loss.

When uranium nuclei go through radioactive decay, a number of their mass is transformed into kinetic energy (the electricity of the transferring particles). This conversion of electricity is determined as a lack of mass. When it decays, a radionuclide transforms right into a one-of-a-kind atom - a decay product. The atoms maintain remodeling to new decay merchandise till they attain a solid country and are now not radioactive. This radioactivity is a part of earth's herbal device and is the principle purpose of warmth in the earth and the using pressure for earth's tectonic device which results in volcanoes, earthquakes and plate tectonics.

Thus, the given statement is true.

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Answer:92.1g

Explanation:

This means that the reaction consumed4.004moles NaCl⋅2 moles Na2moles NaCl=4.004 moles NaConvert this to grams by using the element's molar mass4.004moles Na⋅22.99 g1mole Na=92.1 g

The final pressure if the final volume is 1. 22 L will be 0.4234 atm

To calculate the final pressure of the hydrogen in the balloon if the final volume is 1.22 L, the ideal gas law can be used. The ideal gas law states that PV = NRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature.

Since the number of moles and the temperature is not given, we can assume that they remain constant. So we can use the equation PV = k, where k is a constant.

Given the initial pressure and volume of the hydrogen are 0.95 atm and 0.55 L respectively.

0.95*0.55 = k

so k = 0.5175

then the final pressure can be calculated by:

P1V1 = P2V2

0.950.55 = P21.22

P2 = (0.5175) / (1.22) = 0.4234 atm

The final pressure of the hydrogen in the balloon will be 0.4234 atm.

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We burn the things that have previously grown in the sunlight-carbohydrates. Hydrogen in the carbohydrates burns to form water which is very harmless. The carbon can be recycled into many different compounds.

The carbon in this material becomes carbon monoxide  carbon dioxide, (Poisonous to us mammals) and the carbon or char which can be a nutrient into the soil. Other things that can be burning in the waste will be toxic. Plants will absorb some  worst things that humans will spill out so carelessly like: lead, cadmium, and the other toxic metals—and these toxins are very dangerous in the atmosphere

So we can indeed to alter the composition of our atmosphere by burning things. Once our planet had a carbon dioxide in the atmosphere. It was a hell-hole here. It was very hot and the atmosphere was poisonous to higher life forms. Gradually life on the planet primarily plant life has been changed this atmosphere into something clean and wonderful. But we by our careless behaviour could return it into its original poisonous luckily the huge coniferous forests clean our air of carbon and the other pollution. We are eroding one factor of this margin after the another. Glaciation, wetlands, oceans, coral reefs, wild areas—these are our safeguards and one after another they are being lost.

--The given question is incomplete, the complete question is

"Explain how the following two processes alter the percentage of carbon dioxide in the atmosphere. I. Combustion (3) II. Respiration (3)".

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The statement is False, when lead-209 undergoes beta decay. As the nuclear equation is n ---> p + e- + antineutrino.

Lead-209 is an atom that contains 82 protons and 127 neutrons in its nucleus, meaning that lead-209 is not a neutron. Neutrons are particles that are found in the nucleus of atoms and have no charge. Therefore, lead-209 can't undergo beta decay by emitting a neutron. Beta decay occurs when an unstable nucleus emits a beta particle and an antineutrino, changing the number of protons in the nucleus. The balanced nuclear equation for the beta decay of lead-209 would be Pb-209 (atomic number = 82) --> Bi-209 (atomic number = 83) + e- + antineutrino. The Bi-209 is a isotope of bismuth, which has one more proton than lead-209 and the same number of neutrons.

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Question-- Select True or False: When lead-209 undergoes beta decay the balanced nuclear equation for this reaction is: n ---> p + e- + antineutrino

To solve this we must be knowing each and every concept related to   ideal gas equation. Therefore, the pressure when the volume is doubled is  3atm.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of gas

V= volume of gas

n =number of moles of gas

T =temperature of gas

R = Gas constant = 0.0821 L.atm/K.mol

rearranging the above equation, we get

P₁V₁= P₂V₂

{ (6atm) (10dm[tex]_3[/tex])}  ={ ( P₂) (20dm[tex]_3[/tex])}

P₂ = 3atm

Therefore, the pressure when the volume is doubled is  3atm.

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The occurrence of elements properties in which it repeats every after the eight elements named a periodicity.

Periodicity would be the reappearance of identical features in an element's behavior when it is organized in atomic number-increasing at frequent intervals.

The repeating of a comparable electronic configuration of an element's atoms in its outermost electron shell after such a predetermined regular interval that's what causes periodicity in its properties.

The elements were organized by chemist John A. R. Newland in order of increasing their atomic weight. He gave it the name "the principle of Octaves" and described how a particular collection of qualities recurs every eight places.

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The formula for standard deviation is: = (V1/C1) + (V2/C2) +... + (Vn/Cn).

Calculating the percent relative standard deviation (RSD) of the measurement will allow us to ascertain the degree of uncertainty in a standard solution created by pipetting 20 mL of a 0.2487 M (stock) solution.

The RSD is determined by multiplying the standard deviation by the mean and then by 100. The formula to determine the standard deviation is: = (V1/C1) + (V2/C2) +... + (Vn/Cn).

Where n is the number of measurements, C is the stock solution's concentration, and V is the volume of solution added.

We are unable to compute the RSD for the given information since you have not provided any information regarding the number of measurements taken.

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The electron rule is broken in the diagram is: (c) Pauli Exclusion Principle.

An electron is a subatomic particle with a negative electric charge. It is found in atoms, and is the main component of electricity. Electrons are incredibly small, measuring only a fraction of a nanometer, and they are around 2000 times lighter than the smallest atom. Electrons are governed by the laws of quantum mechanics and they are move around the nucleus of an atom in discrete orbits. Electrons are responsible for chemical bonding between atoms, and they are essential for the formation of molecules.

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On adding 200g hydrochloric acid to excess calcium carbonate, the percent yield of carbon dioxide is equal to 82.84%.

200g of HCl was added to an excess amount of calcium carbonate to produce 100g of carbon dioxide along with water and calcium chloride. The reaction is written as:

CaCO₃ + 2HCl → H₂O + CO₂ + CaCl₂

Since calcium carbonate is excess, two moles of hydrochloric acid gives rise to one mole of carbon dioxide.

To calculate the percent yield, we can use stoichiometry,

The molar mass of hydrochloric acid = 36.46 g/mol

The molar mass of carbon dioxide = 44.01 g/mol

To calculate theoretical yield,

200g HCl/1 × 1 mole HCl/36.46g HCl × 1 mol CO₂ /2mol HCl × 44.01 mol CO₂/ 1 mole CO₂

= 120.707 g

To calculate the percent yield,

The amount of CO₂ produced = 100g

Dividing 100 by the theoretical yield

=  100/120.707 = 0.8284

Now multiplying the value by 100

= 0.8284 × 100 = 82.84 %

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