Plz help me I am!!!!

The half-life of a reaction is the time it takes for the concentration of a reactant to decrease to half its initial value. In a first-order reaction, the rate of the reaction is directly proportional to the concentration of the reactant. This means that the rate of the reaction depends on the concentration of compound A.

To calculate the half-life of compound A, you can use the equation:

half-life = (ln(2)) / k

where k is the rate constant for the reaction.

Plugging in the values given in the question, we get:

half-life = (ln(2)) / 0.45

This simplifies to:

half-life = 1.44 / 0.45

Which gives us a final result of:

half-life = 3.2 hours

So the half-life of compound A at 250°C is approximately 3.2 hours.

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Shroud's vintage t=4.28×10 3yr If the cloth veil from a mummy has a 14C14C energy of 10.0 disintegrations for minute per kg of carbon in comparison to live things that experience

When a government is no longer in effective control, the third component necessary for a state to exist, state structures appear to fall apart. Diverse regions of the nation's borders may be affected by this at varying intensities.

t = k1 ln N 0N t t = - dfrac 1 1.21 times 10-4 text year 1 ln dfrac 9.7 16.3

t=1.21104 yr1 1 ln 16.39.7 t = 4.28times 103 textyr

t=4.28×10 3 yr

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When a food is burned, all the minerals are found in the ash. Therefore, the correct option is option A which  accurately describes minerals among all the given options.

A mineral is unique from its synthetic analogues, which must be generated through natural processes by definition. Artificial minerals, such as emeralds, diamond, sapphires, and other expensive gemstones, are routinely made in industry and scientific facilities and are frequently almost similar to their biological counterparts.

There are thousands of known mineral species, with around 100 of them constituting the primary dissolved minerals of rocks; they are known as rock-forming minerals. When a food is burned, all the minerals are found in the ash.

Therefore, the correct option is option A.

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The complete Lewis electron-dot diagram for ethyne is shown in the attached diagram below:

A lewis electron dot structure can be utilized to represent the number of bonds, the lone pairs left in the atoms, and the bonding atoms in the molecule.

Solid lines are used to represent the bonds between atoms that are directly bonded to one another and excess electrons are denoted as dot pairs and are represented next to the atoms.

As the valence electrons of each carbon atom are equal to 4 from the electronic configuration of the carbon atom. First, the total number of valence electrons in a molecule is 4 + 1 + 1 + 4 = 10.

As each carbon atom needs only 4 electrons to complete its octet. As the octet completes, the rest of the electrons are assigned as the lone pairs of atoms. But there are no lone pairs in the molecule of the ethyne.

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Answer:

180 ml

Explanation:

For the given question, statements A and B are true. So, Option E is correct as the work done given is negative.

According to the First Law of Thermodynamics, energy can only be changed from one form to another through the interplay of heat, work, and internal energy. Under no circumstances can energy be created or destroyed. It can be represented as:

ΔU = q + w

where,

ΔU = Total internal energy of the system

q = the heat that is transferred from a system to its surroundings

w = work done on the system or by the system

It is given in the question that q = 25 kJ and w = -15 KJ

So we get from the above equation-

ΔU = 25 - 15 = 10 KJ

The negative amount of heat that the environment has absorbed will be the value of internal energy.

Thus, the negative sign of work done shows that the work is done by the system on the surroundings while increasing the temperature of the surroundings.

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Molecule move quickly at high temperatures & low pressures. These intermolecular attractive forces diminish as a consequence, and the real gas starts to behave like that of an ideal gas.

Many gases, including gas, oxygen, hydrogen, noble metals, some denser hydrocarbons like atmospheric co2, and combinations like air, can be classified as ideal gases if certain parameters are kept within reasonable bounds over a wide range of temperatures and pressures.

Whenever the pressure is expressed in kPa, the real gases standard is found to be 8.314J/Kmol. The pressure, quantity, temperature, & number of molecules of an ideal gas are all related by a single equation known as the ideal gas law.

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Electrolysis of water produces hydrogen and oxygen gases as it's products.

Electrolysis is defined as a process that makes of an electric current to drive a non-spontaneous chemical reaction. It is an important process for purification and extraction of metals from their ores.It makes use of an electrolytic cell in which two electrodes are present.

The two electrodes are the cathode and anode  where reduction and oxidation reactions take place respectively.In the electrolysis of water hydrogen is collected at cathode and oxygen is collected at anode.

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The energy level of the products is lower than the energy level of the reactants, and energy is released throughout the reaction. (Option A)

Chemical processes known as exothermic reactions generate heat. When heat is transferred from the system to its surroundings, as described, the heat flow q is considered negative. Therefore, the H of reaction is negative for exothermic reaction processes.

Therefore, a reaction is exothermic and its enthalpy will be negative if it releases more energy than it takes in. Consider this as a certain quantity of heat evaporating from (or being removed from) the reaction. Endothermic reactions have positive enthalpies because they absorb or use more energy than they produce.

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The name of the compound (CH3CH2)2COHCH3 is butane-2,3-diol.

The compound is an alcohol, which means it contains a hydroxyl (-OH) group. The prefix "butane-" indicates that it has four carbon atoms in a straight chain, and the suffix "-diol" indicates that it contains two hydroxyl groups. The prefix "2,3-" specifies the positions of the hydroxyl groups on the carbon chain.

Butane-2,3-diol is also known by other names, including 2,3-butanediol, 2,3-dihydroxybutane, and 1,4-butanediol. It is a colorless, viscous liquid that is used in the production of plastics, solvents, and other chemicals.

The name of (CH3CH2)2COHCH3​ compound is butane- 2,3- diol.

The organic substance 2,3-butanediol has the formula (CH3CHOH)2. It falls under the vic-diol category. It exists as a chiral pair, three stereoisomers, and a meso isomer. All liquids are colorless. Precursors for various polymers and insecticides are examples of applications.

A butanediol with hydroxylation at C-2 and C-3 is known as butane-2,3-diol. It is a secondary alcohol, a glycol, and a butanediol.

Among its many possible uses are the production of printing inks, perfumes, synthetic rubber, fumigants, antifreeze agents, fuel additives, foodstuffs, and pharmaceuticals. 2,3-Butanediol (2,3-BD) is a promising bulk chemical.

Alcohols classified as primary have just one alkyl group on which the carbon atom of the hydroxyl group (OH) is connected. These major alcohols include, for instance, ethanol, methanol (propanol),

Thus, The name of (CH3CH2)2COHCH3​ compound is butane- 2,3- diol.

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The bonds ionic and covalent are in the NH4Cl as it has the one ionic bond and 3 covalent bonds.

There is definitely a coordinate bond (that's definitely a type of covalent bond wherein handiest one of the collaborating atoms donate each in their electrons to shape a covalent bond) among lone pair of nitrogen in ammonia(NH3) and a proton(H+ ion),which as a result creates an ammonium ion(NH4+).

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Among all the statements, statement A is incorrect that is the n = 2 energy level has no d orbitals.

The angular momentum quantum number (l)- The orbital form is determined by this integer with the values l = 0, 1, 2,...,  n - 1.

Because of this, an orbital with n = 1 can only have one value of l, l = 0, while an orbital with n = 2 can have both l = 0 and l = 1. The orbital's overall dimensions and energy are determined by the primary quantum number. The orbital's form is determined by the l value. Subshells are formed by orbitals with the same value of l. Additionally, the angular momentum of an electron in this orbital increases with the angular momentum quantum number.

The d orbitals are the orbitals with l = 2. Then, the value of l is -

I = n-1 = 2 -1 = 1

The p orbitals are represented by the value l = 1 and not the d orbitals.

Thus, statement A in incorrect.

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Alkyl halides are produced by adding HBr to alkenes.The pi bond of the alkene functions as a weak nucleophile & reacts with electrophilic proton of HBr, which is a helpful way to conceptualize the reaction.

A 3-membered ring intermediate is produced as a result of the alkene acting as a nucleophile in this reaction and attacking the electrophilic bromine.The carbon that is most capable of stabilizing positive charge then is attacked from of the back side [akin to a backside attack inside the SN2 Mechanism] to produce the trans product.

The free-radical mechanism governs the addition reaction with HBr to an asymmetrical alkene inside the presence of peroxide.Here, an alkene interacts with a bromine radical to make an anti-Markovnikov product.

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The largest percent composition by mass of carbon is d)CH₄ .So,correct option is d.

We need to calculate the molecular mass of each of the compound and then check how much by mass carbon is present in the compound.

a)Molecular mass of calcium carbonate (CaCO₃) is =40+12+3ˣ16=100g

Now,we know that carbon has molecular mass=12g

So,percentage composition of carbon in CaCO₃=(12/100)ˣ100=12%

b)Similarly,molecular mass of carbon dioxide (CO₂)=44g

So,percentage composition of carbon in carbon dioxide is =(12/44)ˣ100=27.27%

c)Molecular mass of Sodium bicarbonate(NaHCO₃)=23+1+12+3ˣ16=84g

So,percentage composition of carbon in NaHCO₃=(12/84)ˣ100=12.85%

d)Molecular mass of methane(CH₄)=12+4ˣ1=16g

So, percentage composition of carbon in methane=(12/16)ˣ100=75%

We can see that by mass largest amount of carbon is present in methane(CH₄).

Hence,correct option is d.

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(Complete question) is:

Which of the following has the largest percent by mass of carbon?

a)CaCO₃

b)CO₂

c)NaHCO₃

d)CH₄

According to the tlc experiment, chemicals that have a low affinity for the stationary phase and a high affinity for the mobile phase will go the farthest.

A material that has been chemically linked by the joining of two or more distinct components. Sea salt (NaCl), which itself is derived first from elements sodium and chloride, as water (H2O), which is created from the components hydrogen and oxygen are two such examples of compounds.

Any material composed of two or more separate chemical elements mixed together in a certain proportion is called a compound. The interaction of the elements creates chemical connections that are hard to break. Shared or exchanged electrons between atoms cause the formation of these bonds.

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The Reaction energy change = -456 kJ releases most energy to the surroundings. Option A is correct here

In a chemical reaction, one or more substances—also known as reactants—are changed into one or more additional substances—also known as products. Chemical elements or chemical compounds make up substances.

Chemical reactions are the processes by which a substance or substances change chemically to create a new substance or substances with entirely new attributes. The most energy is released into the environment via the reaction energy change, which is -456 kJ.

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Answer:

When copper is heated in an atmosphere of hydrogen, the hydrogen gas can react with the oxygen present on the surface of the copper to form water. This reaction is known as reduction. The equation for this reaction is:

2H2 + O2 → 2H2O

In this reaction, the oxygen atoms in the copper are reduced (i.e., they gain electrons) and the hydrogen atoms are oxidized (i.e., they lose electrons). As a result, the oxygen is removed from the surface of the copper, leaving it oxygen-free.

This process is often used to purify copper and remove impurities, such as oxygen, that may be present on the surface of the metal. It is also used to produce high-purity copper for use in electrical and electronic applications, where the presence of oxygen can affect the conductivity of the metal.

The RMS speed of an oxygen molecule at 0° temperature is 14.5971m/sec and it move   0.342 times per second back and forth.

We know that RMS speed of molecule is given by the formula=√(3RT /M)

where R is the gas constant,

T is the temperature of molecule

and M is the molecular mass of the molecule.

Now,for oxygen molecule,we know that oxygen have =32g/mol,and temperature in kelvin is C+273=0+273=273K.

So,on putting the value in above formula

=>RMS speed=√(3 × 8.314× 273) / 32

=>RMS speed=√6809.166/32

=>RMS speed=√212.786

=>RMS speed=14.5871m/sec

Now,we need to apply the distance-speed formula for calculating the time.

We have distance as 5m,speed as 14.5871m/sec and t=?;

5=14.5871 × t

=>t=5/14.5871

=>t=0.342sec

Hence, RMS speed is 14.5871m/sec and oxygen molecule will travel back and froth 0.342 times in 1 sec .

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For a first reaction its exothermic reaction ,increases, decreases.

For second reaction its exothermic reaction, increases, decreases.

For third reaction its endothermic reaction , increases, decreases.

What principle underlies Le Chatelier?

Le Chatelier's principles, sometimes known as the equilibrium law, allow for the prediction of a system in chemical equilibrium (such as the change in temperature or pressure).

The equilibrium position moves to the right at low temperatures.

Please see the accompanying file for a more thorough explanation.

CoCl₄²⁻ (aq)  ⇆ Co²⁺ + 4Cl⁻

1. Exothermic -

At low temp, the position of equilibrium shifts to right side and forms more pink color.

when the temp decreases. the K increases

[tex]K = \frac{[Co^{2+} ][Clx^{-} ]^{4} }{CoCl_{4} ^{2-} }[/tex]

2. At low temperature, more Co²⁺ produces and K values will increase as equilibrium shifts towards right.

Higher [Co²⁺] = Hugh K value

3. When temperature decreases the concentration of CoCl₄²⁻ decreases.

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The slope of a distance-time graph for this motion will have a straight line to represent that the object in motion is at a constant speed.

A distance-time graph depicts how far an object has traveled in a specified amount of time. It is a simple line graph that depicts distance versus time findings. The Y-axis represents distance. On the X-axis, time is plotted.

The slope of the distance-time graph should always be constant because the bike is moving at a constant speed. As a result, the graph will be a straight line through the origin.

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The compounds in each of the following groups in order of increasing acidity or basicity, as indicated are basicity: Mg(OH)2,NaOH and Si(OH)4.

The base MgOH are more weaker as compared to that of the NaOH as these are really less in electronic configuration and has the lowest electrons in NaOH is eventually more stronger than all bases as it has the best conjugation basics property that defines the basic structure and strength.

The NaOH is stronger among all as it is having higher basic properties that's fir the basicity of any base. The Si(OH)4 are the basic that has the lesser basic properties than that of the NaOH and MgOH.

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H will have the longest wavelength emission line for the transition between the n initial = 2 and n final = 1 levels.

A movement (or leap) of an electron from one energy level to another within an atom or artificial atom is referred to as an atomic electron transition. It seems discontinuous because the electron "jumps" from one quantized energy level to another in a matter of nanoseconds or less.

Electronic transitions occur in atoms and molecules as a result of electromagnetic radiation absorption or emission (typically UV or visible). Planck's equation, E = h, relates the energy change associated with a transition to the frequency of an electromagnetic wave. Transitions between these permitted orbits occur in photon absorption or emission. A photon is released when an electron transitions from a higher-energy orbit to a more stable orbit.

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The green bottom curve represents the catalysed reaction.

It is common practise to use catalysed reactions to quicken a particular chemistry's progress. The catalyst's main function is to offer the reaction a different, lower-energy pathway.

In a catalysed reaction, the reactant molecules readily pass the activation energy barrier and produce products. As a result, the activation energy of an uncatalyzed reaction is higher than the activation energy of a catalysed reaction.

For catalyzed reaction activation energy lower than uncatalyzed reaction. The complexity of the collisions necessary to reach a transition state means that without the catalyst, the Ce4+ ions and Tl+ ions must directly react in a termolecular reaction, which will be substantially slower.

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Answer:

it act has a catalyst

Explanation:

sulphuric acid is a catalyst that is used in the preparation of chrom alum

The energy of a photon is hv. Where h is plank's constant and v be the frequency. The frequency of a photon with an energy of 3.75 × 10⁻²¹ J is 5.66 × 10¹² Hz.

Frequency of a wave is the number of wave cycles per unit time. It is the inverse of the time period. Thus, has a unit of s⁻¹ which is equivalent to Hz.

Frequency of a wave is directly proportional to the energy.

The energy of a photon = hv

h is the planck constant = 6.62 × 10⁻34 J.s

Given the energy of a photon = 3.75 × 10⁻²¹ J

Thus, frequency = energy/planck's constant

= 3.75 × 10⁻²¹ J/ 6.62 × 10⁻34 J.s

= 5.66 × 10¹² Hz.

Therefore, the frequency of the photon is 5.66 × 10¹² Hz.

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The flash of green light 525 nm that contains 189kJ of total energy is  2.39 ×10^29 photons.

The formula below gives the energy EE of a single photon of wavelength lambda.

E = hc/λ, where c is the speed of light and h is the plank constant, with a value of 6.62607015 ×10^34.

To determine the overall number of photons n in a green light flash (525 mm) with a total energy of 189 kJ.

We'll apply the following formula.

n= Et/ E

When we enter the given values into the formula, we see that n= Et/E.

= [tex]\frac{189 *10^3}{6.62607015 *10^−34 × 3*10^8}/ 525 *10^-3[/tex]

Therefore, there are 2.39 ×10^29 photons in a green light with 189 kJ of energy.

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All transporters were reduced as cytochrome oxidation is inhibited by cyanide. Since there is no terminating electron acceptor when O2 is absent, all carriers undergo reduction.

A negative charges particle known as an electron can be either independent or attached to an atom (not bound). Another of the three main types of elements within an atom is an electrode that is bonded to it; the other couple are protons & neutrons.

An electron's energy is determined by where it is in relation to the atom's nucleus. The distance an electron inside an atom has to travel from the nucleus depends on its energy level.

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The temperatures shown to the nearest 0.5°C is 42.5°C.

°C (Celsius):

Hence, as per the given image the temperatures shown to the nearest 0.5°C is 42.5°C.

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Answer:

Photosynthesis would happen in the plant, while cellular respiration would happen in the plant and the fish. In the plant, photosynthesis occurs when light energy is converted into chemical energy used for growth and development. In fish, cellular respiration occurs when the fish takes in oxygen from the water and uses it to convert energy from food into usable energy...

Explanation:

The radioactivity A of a drop of iodine I-131 if the mass of the drop is 1.5 g and the period is 13h is:  1.29 x 10^(-11) disintegrations/second.

Generally, To find the radioactivity of a drop of iodine I-131, you will need to use the following formula:

A = (N/M) * ln(2) / T

where:

To use this formula, you will need to know the atomic mass of I-131, which is about 130.906 amu, and its half-life, which is about 8.04 days. You will also need to convert the mass of the drop from grams to atomic mass units, which can be done by dividing the mass by the atomic mass of carbon-12 (12 amu).

First, convert the period from hours to seconds:

13 hours = 13 * 60 minutes/hour * 60 seconds/minute

= 5,040 seconds

Then, convert the period from seconds to days:

5,040 seconds = 5,040 seconds / (24 hours/day * 60 minutes/hour * 60 seconds/minute)

= 0.6 days

Then, calculate the half-life in seconds:

8.04 days = 8.04 days * 24 hours/day * 60 minutes/hour * 60 seconds/minute

= 691,840 seconds

Then, use the formula above to calculate the radioactivity:

A = (N/M) * ln(2) / T = (N/130.906 amu) * ln(2) / (691,840 seconds)

= (1.5 g / 12 amu) * ln(2) / (691,840 seconds)

= 0.125 * ln(2) / (691,840 seconds)

= 0.08867 * (1/691,840 seconds)

= 1.29 x 10^(-11) disintegrations/second

So the radioactivity of the drop of iodine I-131 is approximately 1.29 x 10^(-11) disintegrations/second.

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