. at the beginning of his experiment, josh has 10 g of element a and 10 g or element b. when finished with the experiment, josh has 20 g of element a and b combined. this demonstrates what law?

Explanation:

In an endothermic energy, energy is taken into the reaction system from the surroundings whereas, in an exothermic reaction energy is released out as thermal energy.

The normal, low-level measurement on the detector when dealing with a Geiger-Mueller tube to detect nuclear radiation is known as background radiation.

This is referred to as the emission or transmission of energy through space or a material medium. This is usually in the form of waves or particles and it is used for various purposes such as in treatment of diseases.

Radiation can also cause a change in DNA thereby resulting in mutation when exposed to large amounts. Geiger-Mueller tube is used to detect nuclear radiation by scientists for various operations.

In a scenario where there is a low count rate on the detector, it means small amounts were released which is known as the background radiation and it is responsible for the normal, low-level measurement.

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One atom thick film of carbon known as graphene is 200 times stronger than steel and one hundred times thinner than a sheet of paper.

1 atom thick

Pure carbon atoms are arranged in a hexagonal lattice in a single layer to form graphene, which is held together by sp2 bonds. Graphite is composed of layers of graphene. The thinnest material known to exist is graphene, which measures one atom thick (0.345Nm). Actually, it is two-dimensional.

A hexagonal honeycomb lattice securely holds a single layer (monolayer) of carbon atoms together to form graphene. It is an allotrope of carbon with sp2-bonded atoms arranged in a plane and a molecular bond length of 0.142 nanometers.

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The number of ethanol molecules in the sample are

The molecular mass of ethanol is 45.07 g/mol

Now to calculate the number of molecules of ethanol:

72.75 × (1 mol/46.07)

1.5 moles

Now multiply it with by Avogadro's number which is 6.02 X 10^23 molecules / mole.

1.5  × 6.02 X 10^23

9.03 X 10^23 molecules.

Hence the number of ethanol molecules in the sample 9.03 X 10^23 molecules.

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The density of the solid substance if a cube  measuring 2.02cm on one side having a mass of 101g is  12.254g/cm^3.

What is meant by density?

Density can be defined as the relationship between mass of a substance and volume of that substance. Density explains how tightly the atoms in a substance is packed together.

Density of the substance can be calculated by dividing mass by volume of the substance.

Volume of the cube = LxBxH = 2.02cm x 2.02cm x 2.02cm = 8.242 cm^3

Density = mass/volume = 101g/8.242cm^3 = 12.254 g/cm^3

Therefore, the density of the solid substance if a cube  measuring 2.02cm on one side having a mass of 101g is  12.254g/cm^3.

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40.4 C

So far q(rxn) = q(water) + q(CaCl2) (136g)(4.184J/°Cg)(Tfinal - 25.0°C) = (125g)(4.184)(Tfinal - 25.0°c) + (11g)c(Tfinal - 25.0°C).

The specific heat capacity is measured in J/(kg K) or J/(kg °C), and it is the amount of heat (J) absorbed per unit mass (kg) of the material when its temperature rises by 1 K (or 1 °C).The average kinetic energy of the atoms or molecules in the system is measured by temperatures. The zeroth law of thermodynamics states that when two objects are in thermal equilibrium, no heat is transferred between them, resulting in an equalisation of their temperatures.

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If the arrow is pointed this way ->, there is only one H atom on the reactant side; however, if it is pointed this way <- , there are two H atoms. The correct option is A.

The majority of stars and the sun include it, and the giant Jupiter is primarily made of it. Water is where you'll find the most hydrogen on Earth. Less than 1 part per million cubic volume is all that is found of it as a gas in the air.

According to the Los Alamos, hydrogen makes up more than 90% of all atoms, which is equivalent to three quarters of the universe's mass. Hydrogen is named after the Greek terms hydro for "water" or genes for "forming."

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The complete question is -

Mg(OH)2 + NaCl ® MgCl₂ + NaOH

How many hydrogen atoms are on the reactant side?

A-1

B-2

C-4

D-8

The given question is incomplete and the complete question is

When 2 moles of Fe(s) react with Cl2(g) to form FeCl3(s) according to the following equation, 799 kJ of energy are evolved.  Is this reaction endothermic or exothermic and What is the value of q

When 2 moles of Fe(s) react with Cl2(g) to form FeCl3(s) according to the following equation, 799 kJ of energy are evolved then the reaction is exothermic reaction and the value of q is -1598 kJ

Mole is the amount of substances of a specified elementary entity

2 moles of Fe(s) react with Cl2(g) to form FeCl3(s)

Energy = 799 kJ

We have to calculated reaction endothermic or exothermic = ?

The value of q = ?

So according to the reaction 799 kJ of energy are evolved it means that the enthalpy is negative as the reactant have more energy than the product and which means this is an exothermic reaction

And here we know that enthalpy of reaction is -799kJ/mol and considering the reacted 2 mole of solid iron then

q = 2 mol×-799kJ/mol

q = -1598 kJ

-1598 kJ energy are evolved when 2 mole of solid iron is react

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Maximum amount of ethane formed is 9.47660606 grams .

What is Chemical reaction ?

There are chemical reactions taking place all around us. Nothing could be further from the reality, despite the fact that we occasionally link chemical processes with the sterile surroundings of the test tube and the lab. A staggering, nearly incomprehensible variety of new substances and energy changes actually result from the enormous number of alterations that occur in our environment every second of every day.

Chemical reactions happen whether or not you want them to in nature, where they can be considerably less controlled than in a lab. They can also be more messier. Whether it be a forest fire that is blazing.

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Answer:

Together, the number of protons and the number of neutrons determine an element’s mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number. A property closely related to an atom’s mass number is its atomic mass.

Explanation:

The copper bars and the surrounds would transfer energy energy be different if the bars were in an open system.

Systems that are isolated are ones whose energy is constant at all times. Heat is neither generated nor absorbed in isolated systems. An illustration of such an isolated system Thermos flasks are the ideal illustration of isolated systems. There is neither a gain nor a loss of energy because the thermally flask is completely insulated.

As a result, isothermal processes are not able to occur in closed systems. Q. In a thermodynamics cycle, the unit is in contact with an outside source of heat, and changes happen gradually to make regulating the temperature easier. An adiabatic process isolates the system.

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Taking into account the definition of dilution, if 150 mL of a 2.5M KBr solution is diluted to 500 mL, the new concentration of KBr is 0.75 M.

A stock solution is a highly concentrated solution. Stock solutions are very useful because they allow a portion to be diluted to obtain the desired concentration.

Then, dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

In this case, you know:

Replacing in the definition of dilution:

2.50 M× 150 mL= Cf× 500 mL

Solving:

(2.50 M× 150 mL)÷ 500 mL= Cf

0.75 M= Cf

In summary, the new concentration of KBr is 0.75 M.

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You can find the mass and volume of the pure metal then compare the density with the table of densities to determine which metal.

Density is a term used to describe how tightly a substance is packed. It fits that criteria of mass per unit volume. Formula for Density or Density Symbol: D The formula is: = m/V where is the object's mass, m is its density, and V is its volume. The term "mass" is used to describe how much matter there is in a thing. Mass is often represented in kilogrammes (kg) or grammes (g) (kg). The most common units of mass measurement are kilogrammes (kg) and grammes (g). No matter where in the cosmos it is or how much gravitational force is exerted on it, mass is a measure of how much matter there is.

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K+ has the greatest nuclear charge (Z = 19), its radius is smallest, and S2− with Z = 16 has the largest radius.

What is atomic radius ?

Atomic radius is generally given as the total distance from the nucleus to the outermost orbital of an electron. Simply put, it can be defined as analogous to the radius of a circle, where the center of the circle is the nucleus and the outer edge of the circle is the outermost orbit of the electrons. As you begin to move or move down the periodic table, trends emerge that help explain how atomic radii change.

The net nuclear charge (Zeff) of an atom is the net positive charge experienced by the valence electrons. Not all of the positive charge is seen by valence electrons, as some of the positive charge is masked by core electrons. A detailed explanation of shields and effective nuclear charges can be found here. Zeff greatly influences the atomic size of an atom. So a decrease in Zeff results in an increase in atomic radius. This is because the electrons are more shielded from the nucleus and the attractive force between the nucleus and electrons is reduced. Zeff decreases from right to left down the periodic table down the group, so the atomic radius increases as the group moves down the periodic table from right to left.

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The claim that an ultrasonic scaler can be utilized for both supragingival and subgingival scaling during routine dental prophylaxis is untrue.

During a dental prophylaxis, the teeth are given a thorough cleaning. Prophylaxis is a crucial dental technique for halting the spread of gingivitis and periodontal disease.

Periodontal disease and gingivitis can be brought on by bacteria from plaque that colonize on gingival (gum) tissue above or below the gum line. The body's continuing inflammatory response is brought on by these bacterial colonies' extreme inflammatory reactions and irritation. As the body starts to gradually erode bone and gum tissue, the teeth might shift, become unstable, or even fall out totally. There are more bacteria in the deeper pockets that develop between the gums and teeth.

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By finding the serial fraction, we arrive to the aforementioned Karp-Flatt metric.

A measure of code parallelization in systems with parallel processors is the Karp-Flatt metric. This metric exists in addition to Amdahl's law and Gustafson's law as a measure of the level of parallelization of a specific computer code. In 1990, Horace P. Flatt and Alan H. Karp made the suggestion.

The effectiveness of a parallel algorithm operating on a parallel processor can be evaluated in a variety of ways. The Karp-Flatt metric identifies a statistic that highlights performance characteristics that are difficult to identify from other metrics. Amdahl's Law has the following pseudo-"derivation," .

Note that the left hand side reflects a metric quantity rather than a quantity that was derived mathematically, indicating that this is not a "derivation" from Amdahl's law. The analysis above only demonstrates that the Karp-Flatt measure and Amdahl's Law are compatible.

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An electron of mass travelling in a circular orbit with a constant speed of v makes up a hydrogen atom. The orbital radius is 5*10^- 11 meters. The lepton particle family's first generation includes electrons.

In a hydrogen atom, the electron orbits the nucleus in a circle with a radius of 5*10^- 11 metres. It lasts for 1.5*10^16 seconds. The electron motion is accompanied by a current (electromagnetic charge: 1.6*10^19 C).

The electron is a subatomic particle with the symbol e or and an electric charge of one elementarily negative charge of hydrogen atom. Because they are thought to be elementary particles and do not have any known components or substructure, electrons are part of the first generation of the lepton particle family.

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108.10 g of sodium chloride will be produced if 42.5 grams of sodium metal react with excess chlorine.

The mechanism that chemists employ to quantify quantities in reactions is known by the fancy name of "stoichiometry." The coefficient ratio established using balanced reaction equations is used to establish links between the reactants and products in reactions.

Equation formed:

2Na + Cl₂ = 2NaCl

Molar mass :

Sodium (Na) - 23 g/mol

Chlorine (Cl₂) - 35.5 × 2 = 71 g/mol

Sodium chloride (NaCl) = 23 + 35.5 = 58.5 g/mol

molar stoichiometric ratio of sodium & chlorine in reaction = 2 : 1.

42.5 grams of sodium contain 3.4/23 or 1.848 moles.

1 g of chlorine has 0.014 moles, or 1/71 of a mol.

Only 1.848/2 = 0.924 mol of chlorine are required to completely transform 1.848 mol of sodium into sodium chloride. Sodium is the limiting reactant, whereas chlorine is the surplus reactant.

In the reaction, the mole ratio of sodium to sodium chloride is 2: 2, which may be expressed as 1: 1.

1.848 mol of sodium utilized equals 1.848 mol of sodium chloride generated.

Molar mass equals moles of sodium chloride times the mass of 1.848 mol of sodium chloride.

m = (58.5 g/mol) × 1.848 mol

m = 108.10 g

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The primary difference between the oxidation of glucose to CO₂ by glycolysis and the critic acid cycle vs by the pentose phosphate is the glycolysis occurs in cytosol. to CO₂ is release of CO₂ is in mitochondria and in the pentose phosphate CO₂ is generated in the cytosol.

When the glucose oxidation takes place  by glycolysis and the citric acid cycle , the total catabolism will occur. The energy is released and this energy is trapped in ATP. in this glucose is catabolizes. in pentose phosphate  CO₂   is generated in the cytosol.

Thus, The primary difference between the oxidation of glucose to CO₂ by glycolysis and the critic acid cycle vs by the pentose phosphate is the glycolysis occurs in cytosol. to CO₂ is release of CO₂ is in mitochondria and in the pentose phosphate CO₂ is generated in the cytosol.

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Answer:

Explanation:nitrous acid

the WASB has a slightly acidic equivalence point and SASB has a slightly basic equivalence point. This is because WASB has a higher concentration of hydronium ions than SASB.

Hydronium ions play an important role in acid-base reactions. It is the hydrogen ion that is released or taken up in the acid-base reaction. The higher the concentration of hydronium ions, the more acidic the solution. In an acid-base reaction, an acid donates a hydrogen ion to a base. Bases accept hydrogen ions. This creates new water molecules. The equivalence point is the point at which an acid and a base react with 1:1 ratio. At this point the solution is neutral. If the acid has a higher concentration of hydronium ions than the base, the equivalence point is slightly acidic. This is due to the presence of more hydronium ions than at the start of the reaction. If the base has a higher concentration of hydronium ions than the acid, the equivalence point is slightly basic.

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The rate of reaction when 0.4g of zinc trioxocarbonate (iv) reacted with dilute hydrochloric acid to produce zinc chloride and carbon (iv) in  2 minutes is 0.0016 mol/min.

The rate of a reaction is the time taken for product molecules to appear or the time taken for reactant molecules to be converted.

Or

The equation of the reaction is given below:

ZnCO₃ (s) + 2 HCl (aq) ---> ZnCl₂ (aq) + H₂O (l) + CO₂ (g)

Molar mass of zinc carbonate = 125.39=8 g/mol

Moles of zinc carbonate converted = 0.4 / 125.38

Moles of zinc carbonate converted = 0.0032 moles

Time taken = 2 minutes

Rate of reaction = 0.0032/ 2

Rate of reaction = 0.0016 mol/min

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The chemicals that accumulate in soil and water as a result of car emissions, improperly disposed waste, industry, and agriculture are known as persistent organic pollutant.

Organic molecules that are resistant to environmental deterioration through chemical, biological, and photolytic processes are persistent organic pollutants, sometimes referred to as "forever chemicals."

They are dangerous compounds that have a negative impact on the environment and human health all over the world.

POPs are compounds that are persistent in the environment, bioaccumulate in the food chain, and have the potential to have negative impacts on both human health and the ecosystem.

Thus, persistent organic pollutants are hazardous compounds that have a negative impact on the environment and human health all over the world.

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The frequency of a wave whose wavelength is 5.67 × 10-⁷m is 5.3 × 10¹⁴Hz.

Wavelength is the length of a single cycle of a wave, as measured by the distance between one peak or trough of a wave and the next.

The wavelength of a wave is often designated in physics as λ, and corresponds to the velocity of the wave divided by its frequency as follows:

λ = v/f

Where;

The frequency is the quotient of the number of times, n, a periodic phenomenon occurs over the time (t) in which it occurs.

According to this question, a wave has a wavelength is 5.67 × 10-⁷m. The frequency can be calculated as follows:

5.67 × 10-⁷ = 3 × 10⁸/f

f = 3 × 10⁸ ÷ 5.67 × 10-⁷

f = 5.3 × 10¹⁴Hz.

Therefore, 5.3 × 10¹⁴Hz is the frequency of the wave

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The calculations about the neutralization reaction show that;

1) hydroxide ions has a concentration of  0.0025 M

2) The amount of the HCl is 0.01 moles

3) The reaction equation is; [tex]KOH (aq)+ HCl(aq) ----- > H_{2} O (l)+ KCl(aq)[/tex]

4) The pH of the solution is 7.

We know that the addition of the potassium to the water is going to lead to a reaction that would produce potassium hydroxide as one of the products of the reaction as we can see it; [tex]2K(s) + 2H_{2} O(l) ---- > 2KOH(aq) + H_{2}(g)[/tex]

Number of moles of the potassium used =  0.195g/39 g/mol

= 0.005 moles

Since we produced 0.005 moles of hydroxide ions, the concentration of the hydroxide ions is; 0.005 moles * 500/1000 L = 0.0025 M

ii) Number of moles of the hydrogen ions =  Concentration * volume

= 0.1 * 100/1000

= 0.01 moles

The balanced reaction equation of the neutralization reaction is given by;

[tex]KOH (aq)+ HCl(aq) ----- > H_{2} O (l)+ KCl(aq)[/tex]

The pH of the solution ought to be seven.

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The oxidation state of an individual bromine atom in NaBrO₃ .express the oxidation state numerically is + 5.

The given compound is as follows :

NaBrO₃  , the oxidation number of Na is +1. the oxidation state of O is - 2. the compound is neutral means all the oxidation number add is equal to zero.

NaBrO₃ =>  + 1 + Br + ( -2 ) × 3 = 0

Br + 1 - 6 = 0

Br - 5 = 0

Br = + 5

Thus, The oxidation state of an individual bromine atom in NaBrO₃ .express the oxidation state numerically is +5

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The pressure, in atm, if the sample of helium is compressed to 125 ml is 2.32 atm

An ideal gas is a theoretical gas composed of many randomly transferring factor particles that aren't difficult to interparticle interactions. the best gasoline idea is beneficial because it obeys the precise gas law, a simplified equation of country, and is amenable to evaluation under statistical mechanics.

Volume is a degree of occupied three-dimensional space. it's far more frequently quantified numerically the usage of SI-derived gadgets or by way of diverse imperial gadgets. The definition of length is interrelated with the extent.

Using the ideal gas equation:-

At constant temperature

Given;

P₁ = 0.9 atm

V₁ = 322 ml = 0.322 L

P₂ = ?

V₂ = 125 ml = 0.125 L

P₁V₁ =P₂V₂

P₂ = P₁V₁ /V₂

    = 0.9 × 0.322 /0.125

    = 2.32 atm

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I would expect the dissolved oxygen levels from wаter entering а lаke to hаve lower thаn the lаke itself becаuse the steаm is аble to hаve wаrm wаter which cаn cаuse the lаke temperаture to be wаrm аlso. Hаving wаrm wаter meаns hаving less dissolved oxygen.

Dissolved oxygen (DO) is the аmount of oxygen thаt is present in wаter. Wаter bodies receive oxygen from the аtmosphere аnd from аquаtic plаnts. Running wаter, such аs thаt of а swift moving streаm, dissolves more oxygen thаn the still wаter of а pond or lаke. Heаlthy wаter should generаlly hаve dissolved oxygen concentrаtions аbove 6.5-8 mg/L аnd dissolved oxygen sаturаtion between аbout 80-120%.

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