What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.010 M CH3CO2Na? Assume that the volume of the solutions are additive and that K a = 1.8 × 10-5 for CH3CO2H.

Answer:

The answer is A.

Hope this helps!

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, the correct option is option A that is isotopes.

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

Isotope refers to each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in atomic mass but not in chemical properties. Isotopes of hydrogen are Protium, Deuterium and Tritium with atomic number 1 and mass number1,2 and  respectively.

Therefore, the correct option is option A that is isotopes.

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Answer:

N, Ne, F, B, Li

Explanation:

Valence electrons are the electrons that are found in the outermost shell in a neutral atom. These five elements are the only one whose valence electrons fall on the same shell. The second shell. Their electronic configurations are as follows:

N: 2,5

Ne:2,8

F:2,7

B:2,5

Li: 2,3

The elements in each of these sets: Nitrogen (N), Arsenic (As), Bismuth (Bi) and Boron (B), Silicon (Si), Arsenic (As) belong to the same group hence their valence electrons are in the same shell. Elements Helium (He), Neon (Ne), Fluorine (F) and Lithium (Li), Nitrogen (N), Fluorine (F) don't belong to the same period, therefore, their valence electrons are not in the same shell.

Looking at the given elements, we can determine which groups have their valence electrons in the same shell by referring to the periodic table. Elements on the same period (row) have their valence electrons in the same shell. Here, the elements are:

Nitrogen (N), Arsenic (As), Bismuth (Bi) belong to group 15 (VA), and hence have valence electrons in the same shell.

Helium (He), Neon (Ne), Fluorine (F) do not belong to the same period and hence their valence electrons are not in the same shell.

Boron (B), Silicon (Si), Arsenic (As) belong to group 13 (IIIA), hence, their valence electrons are present in the same shell.

Lithium (Li), Nitrogen (N), Fluorine (F) do not belong to the same period and hence their valence electrons are not in the same shell.

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The equilibrium constants for the reactions can be calculated using the standard free energy change and the formula K = e^{(-ΔG°/(RT))}, but specific ΔG° values or tables referenced are needed to complete the calculations.

To calculate the equilibrium constant for the reactions at 25 °C, we use the given thermodynamic data from the tables and apply the relation between the standard free energy change (ΔG°) and the equilibrium constant (K). The relation is given by the equation ΔG° = -RTlnK, where R is the gas constant (8.314 J/mol·K), T is the temperature in Kelvin, and K is the equilibrium constant. For each reaction with a given ΔG° value, we can rearrange the formula to solve for K: K = e^{(-ΔG°/(RT))}.

For the provided exercises:

When the necessary thermodynamic data is provided, each reaction's equilibrium constant can be calculated using the formula K = e^{(-ΔG°/(RT))}, with R = 8.314 J/mol·K, and T = 298.15 K (since 25 °C is equivalent to 298.15 K).

Answer:

527.68 mL

Explanation:

We will assume that nitrogen is behaving as ideal gas here.

For ideal gas the gas law is:

[tex]\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{2}}{T_{2}}[/tex]

Where

P1= initial pressure = 740 torr

V1= initial volume = 500mL

T1= initial temperature = 25⁰C = 298 K

P2= final pressure = 760 torr

V2= final volume = ?

T2= final temperature = 50⁰C = 323 K

Putting values in the gas law

Final volume = [tex]\frac{740X500X323}{298X760}= 527.68 mL[/tex]

Answer:

Explanation:

1) Balanced chemical equation (given):

2) Mole ratio:

3) Starting ratio (given)

Since 0.69 > 0.67 means that you start with more Al atoms (4.5 moles) than what are needed to react with the given CuCl units (6.5 mol); i.e. when the 6.5 moles of CuCl are consumed, there will be an excess of Al, and the reaction will stop, because the CuCl is over, meaning the latter is the limiting reactant (it limits the yield).

Answer:

8 proton and 9 neutron.

Explanation:

there are 17 total of protons and neutron

Taking into account the constitution of an atom and the definition of atomic number, the charge of the nucleus in an atom of oxygen-17 is +8.

All atoms are made up of subatomic particles: protons and neutrons, which are part of their nucleus, and electrons, which revolve around them. Protons are positively charged, neutrons are neutrally charged, and electrons are negatively charged (electrons).

In other words, the atomic nucleus is the central part of the atom that is made up of protons and neutrons, while the orbitals or peripheral region is an area where electrons are found.

The neutron is an electrically neutral subatomic particle, while the proton has a positive electrical charge. Electrons have a negative charge, move around the nucleus at different energy levels and are attracted to protons, positive in the atom through electromagnetic force.

Each chemical element is characterized by the number of protons in its nucleus, which is called the atomic number Z.

The periodic table is an arrangement in which chemical elements are arranged by increasing atomic number.

In the periodic table you can see that oxygen has an atomic number of 8. This indicates that in the nucleus of this atom there are 8 protons. Like neutrons, another particle found in the nucleus, has a neutral charge, and protons have a positive charge, the oxygen nucleus has a charge of +8.

In summary, the charge of the nucleus in an atom of oxygen-17 is +8.

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Answer: Saturated fatty acids have more hydrogen than unsaturated fatty acids.

Explanation:

Saturated fat is defined as the fat in which the fatty acid chains contain only single bonds between carbon and carbon atoms. For Example: Cream, cheese etc..

Unsaturated fat is defined as the fat or fatty acid in which one or more double bonds are present between carbon and carbon atoms in the fatty acid chain. For Example: Oleic acid, Myristoleic acid etc..

When double bond emerges in a compound, it leads to the reduction of hydrogen atoms.

Thus, saturated fatty acids have more hydrogen than unsaturated fatty acids.

Saturated fatty acids have more hydrogen atoms than unsaturated fatty acids because of their molecular structure. They only have single bonds which allows each carbon atom to bond with as many hydrogen atoms as possible.

Compared with its corresponding unsaturated fatty acid, a saturated fatty acid has more hydrogen. The difference lies in their molecular structure. Saturated fatty acids have single bonds only, which means each carbon atom in the chain is bonded to as many hydrogen atoms as possible. In contrast, unsaturated fatty acids have one or more double or triple bonds, which reduces the number of hydrogen atoms they can bond with.

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Answer:

An increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass.

F= G^m1m2/r^2

G is universal constant m₁ and m₂ are the masses and r is the distance between them

the gravitational force is directly proportional to the product of masses and indirectly proportional to the square of the distance between them.

Focus on the top part if you do not understand. That is the correct answer

Answer:

An increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass.

Explanation:

Metallic crystals are malleable and ductile due to their unique metallic bonding structure. The free electrons allow metal atoms to move under force without breaking the lattice structure, giving metals their characteristic malleability and ductility.

Metallic crystals, such as copper, aluminum, and iron, are malleable and ductile due to their unique bonding structure, known as metallic bonding. In this structure, metal atoms are closely packed in a lattice pattern. The valence electrons in these atoms are not strongly attracted to their atomic nuclei and hence, act as free electrons. This 'sea' of free electrons allows metal atoms to move and slide past each other under applied force without breaking the lattice structure, thus giving the metal its malleable and ductile properties.  

This malleability and ductility are characteristic properties of metals due to this lattice structure and free electron behavior. The free electrons not only give metals their characteristic electrical conductivity but also the ability to undergo deformation without breaking, which is manifested as malleability (ability to be hammered into thin sheets) and ductility (ability to be drawn into wires).

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Answer:

H₂S; CO₂; SiH₄

Explanation:

London dispersion forces are larger in molecules that are large and have more atoms or electrons.

A. H₂O or H₂S

H₂S. S is below O in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.

B. CO₂ or CO

CO₂. CO₂ has more atoms. It is also linear, so the molecules can get close to each other and maximize the attractive forces.

C. CH₄ or SiH₄

CH₄. Si is below C in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.

Differences are stronger in bigger and heavier atoms than in lighter and smaller ones. Its number of electrons inside a larger atom is, in general, farther away from the nuclei than in a small atom.

Therefore, the answer is "[tex]\bold{H_2S\ , CO_2\ or \ SiH_4}[/tex]"

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Answer:

Explanation:

First, you need to find the empirical formula of the compound (histamine).

To find the empirical formula convert all the data given in mass units (miligrams) into mole numbers.

You do that by using the formula: number of moles = mass in grams / atomic mass.

To find the mass in grams divide the mass in miligrams by 1,000.

Build a table:

Element    mass (g)   atomic mass (g/mol)    number of moles (mol)

C                0.208           12.011                        0.0173

H                0.031            1.008                        0.0307

N                0.146           14.007                       0.0104

Now, find the ratio C:H:N, for which you divide every number of moles by the smallest number of moles: 0.0104:

You must find a multiple that yields 1.665 to a reasonably close integer.

Muliply every amount by 3:

Hence, the empirical formula is C₅H₉N₃.

Now, find the mass of the empirical formula:

Since the mass of the empirical formula is the same of the molecular formula, both formulae are the same.

Therefore, the answer is: C₅H₉N₃ ← molecular formula

Answer:

it will be C5H9N3

Explanation:

because 1st find %age composition then no. of grams then atomic rati and multiple by 3 in thi case and then get the answer

Answer:

Neither accurate nor precise

Explanation:

The values were not near or even the same as the accepted value thus making it neither accurate nor precise.

Answer: neither accurate nor precise​

Explanation:

Accuracy is defined as how close the measured value is to a standard value. For example if the given volume of water is 20 ml and the two measured values are 19 ml and 18 ml then the former measured value is more accurate than the later.  

Precision is defined as how measured values are close to each other. For example, if the length of the wire of 10 m. If the first person measures the length of the same wire thrice and got values 9.7, 9.8 and 9.75 m whereas the second person got values 9.5 , 9.6 and 9.8. In such a case the first person’s measured value is more precise.

Thus as the accepted value is 1.43 and measured values are 1.29 , 1.93 and 0.88 , the experimental data is neither accurate nor precise.

The final concentration after 172 seconds is 1.15 M. To obtain this answer, use the the integrated rate law for the order of reaction. Based on the problem, this is a second order reaction. The units of the rate constant also support that it is a second order reaction.

Further Explanation:

The solution to this problem is straightforward.

STEP 1: Since the reaction is a second order reaction, the integrated rate law will be:

[tex]\frac{1}{C_{f}} = \ kt \ + \frac{1}{C_{i}}[/tex]

where:

C(f) is the final concentration

k is the rate constant

t is the time

C(i) is the initial concentration

STEP 2: Plugging in the values given in the problem into the equation, the following equation should be obtained:

[tex]\frac{1}{C_{f}} \ = (1.30  \ x \ 10^{-3} \frac{ \ 1 }{ \ M-s})(172 \ s) \ + \ \frac{1}{1.54 \ M} \\[/tex]

STEP 3: Using algebra to solve for C(f):

[tex]\frac{1}{C_{f}} = \ 0.87295\\ \\C_{f} = \ 1.14554 \ M[/tex]

Since the given values only have 3 significant figures, the final answer must be expressed with 3 significant figures as well.

Therefore,

[tex]\boxed {C_{f}\ =  \ 1.15 \ M}[/tex]

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Keywords: rate law, second order, integrated rate law

Answer: Option (c) is the correct answer.

Explanation:

Activation energy or free energy of a transition state is defined as the  minimum amount of energy required to by reactant molecules to undergo a chemical reaction.

So, when activation energy is decreased then molecules with lesser amount of energy can also participate in the reaction. This leads to an increase in rate of reaction.  

Also, increase in temperature will help in increasing the rate of reaction.

Whereas at a given temperature, every molecule will have different energy because every molecule travels at different speed.

Hence, we can conclude that out of the given options false statement is that at a given temperature and time all molecules in a solution or a sample will have the same energy.

Answer:

The amount of ionization in solution.

Explanation:

Strong acids ionize fully in solution to release a large number of hydrogen ions responsible for the acidic properties. On the contrary weak acids ionize partially in solution.

In strong acids less energy is required to break the hydrogen- anion bonds.

Answer:

the amount of ionization that occurs in solution

Explanation:

An acid is a substance that interacts with water to produce excess hydroxonium ions, H₃0⁺ in an aqueous solution.

The ionization of acids in solution determines the strength of the acid.

A strong acid is one that ionizes almost completely in solutions and a weak acid is one that ionizes slightly and sets up an equilibrium.

             HCl + H₂0 → H₃0⁺ + Cl⁻ this is the ionization of strong acid

            CH₃COOH + H₂O ⇄  H₃0⁺ + CH₃COO⁻ ionization of a weak acid

when aqueous solution of [tex]CH_{3} NH_{3}Cl[/tex] is taken it dissociates and gives hydronium ion so it is acidic in nature. It is example of hydrolysis reaction

Hydrolysis reaction is a reaction in which bond is broken down with the help of water. Lysis term stands for breaking of anything.

Example: Hydrolysis of ester produces alcohol and acid. Hydrolysis of ester is done both in acid and basic condition.

Any acidic solution that contains acidic acid when put in water produces hydronium ion or we can say that any species that produces hydronium ion in water is acidic in nature.

In our case when [tex]CH_{3} NH_{3}Cl[/tex] is put in water it easily gives hydronium ion in water this shows that it is acidic in nature. and the reaction can be shown as:

[tex]CH_{3} NH_{3}Cl +H_{2}O\rightarrow CH_{3}NH_{2}Cl^{-} +H_{3}O^{+}[/tex]

Thus[tex]CH_{3} NH_{3}Cl[/tex] is acidic in nature and is a hydrolysis reaction.

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An aqueous solution of CH3NH3Cl is acidic due to the hydrolysis reaction that occurs when the compound is dissolved in water, producing CH3NH3+ ions that increase the concentration of H+ ions in the solution.

Aqueous solutions of CH3NH3Cl are acidic due to the hydrolysis reaction that occurs when the compound is dissolved in water. The hydrolysis reaction of CH3NH3Cl can be represented by the chemical equation:

CH3NH3Cl + H2O → CH3NH3+ + Cl- + H2O

In this reaction, CH3NH3Cl dissociates into CH3NH3+ and Cl- ions. The CH3NH3+ acts as a weak acid, releasing H+ ions into the solution, resulting in an overall acidic pH.

Answer : The correct option is, (D) 89.39 KJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

[tex]\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole[/tex]

[tex]\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole[/tex]

The balanced chemical reaction will be,

[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.3562 mole of HCl neutralizes by 0.3562 mole of NaOH

Thus, the number of neutralized moles = 0.3562 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = [tex]137ml+137ml=274ml[/tex]

[tex]\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 274ml=274g[/tex]

Now we have to calculate the heat absorbed during the reaction.

[tex]q=m\times c\times (T_{final}-T_{initial})[/tex]

where,

q = heat absorbed = ?

[tex]c[/tex] = specific heat of water = [tex]4.18J/g^oC[/tex]

m = mass of water = 274 g

[tex]T_{final}[/tex] = final temperature of water = 325.8 K

[tex]T_{initial}[/tex] = initial temperature of metal = 298 K

Now put all the given values in the above formula, we get:

[tex]q=274g\times 4.18J/g^oC\times (325.8-298)K[/tex]

[tex]q=31839.896J=31.84KJ[/tex]

Thus, the heat released during the neutralization = -31.84 KJ

Now we have to calculate the enthalpy of neutralization.

[tex]\Delta H=\frac{q}{n}[/tex]

where,

[tex]\Delta H[/tex] = enthalpy of neutralization = ?

q = heat released = -31.84 KJ

n = number of moles used in neutralization = 0.3562 mole

[tex]\Delta H=\frac{-31.84KJ}{0.3562mole}=-89.39KJ/mole[/tex]

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 89.39 KJ/mole

The enthalpy of neutralization for the reaction of HCl and NaOH, given the provided conditions, is calculated to be 89.39 kJ/mol. The heat absorbed by the reaction solution is computed using the specific heat capacity, the mass of the solution (equivalent to its volume due to the density of water), and the temperature change.

To calculate the enthalpy of neutralization of HCl and NaOH, we first need to determine the heat produced during the reaction. The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is:

HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

We know the following:

First, we calculate the amount of heat (q) absorbed:

q = mass of solution × c × ΔT

Since the density of the solution is the same as water, we use the volume as mass (assuming 1 g/cm³ density), so:

mass = volume of HCl + volume of NaOH = 137 g + 137 g = 274 g

q = 274 g × 4.18 J/g·K × 27.8 K = 31822.32 J

Since the reaction involves equal volumes and concentrations of HCl and NaOH, the number of moles of HCl reacting will be the same as the number of moles of NaOH:

moles HCl = moles NaOH = volume × concentration = 0.137 dm³ × 2.6 mol/dm³ = 0.3562 mol

The enthalpy of neutralization (ΔH_neut) is the heat divided by the number of moles of either HCl or NaOH:

ΔH_neut = q / moles = 31822.32 J / 0.3562 mol = 89384.67 J/mol = 89.39 kJ/mol

Therefore, the enthalpy of neutralization of HCl and NaOH is 89.39 kJ/mol, which is option D.

Answer:

reduces; facilitating

Explanation:

Carbonic anhydrases is a type of metalloenzyme containing zinc metal which catalyze interconversion between the carbon dioxide gas and water and dissociated ions of the carbonic acid.

The reaction that is catalyzed by enzyme, carbonic anhydrase is:

HCO₃⁻ + H⁺ ⇄ CO₂ + H₂O

The enzyme maintains the acid-base balance in the body and helps in the transportation of carbon dioxide through out the body.

The carbon dioxide formed as a by-product of metabolism which is transported to blood in the form of bicarbonate ions by the action of carbonic anhydrase.

Thus,

By converting CO₂ to H₂CO₃, Carbonic anhydrase reduces the PCO₂ in endothelial cells, red blood cells, and plasma, thereby facilitating diffusion of CO₂ from tissue cells to these locations.

Carbonic anhydrase reduces PCO₂ by converting CO₂ to H₂CO₃, which leads to an increase in the diffusion of CO₂ from tissue to blood.

By converting CO₂ to H₂CO₃ (carbonic acid), carbonic anhydrase lowers the PCO₂ (partial pressure of carbon dioxide) in endothelial cells, red blood cells, and plasma, thereby increasing diffusion of CO₂ from tissue cells to these locations. This enzyme catalyzes the reversible hydration of carbon dioxide, forming bicarbonate ions (HCO₃⁻) and protons (H⁺). The reduction in PCO₂ creates a pressure gradient that favors the diffusion of CO₂ from the tissues, where its concentration is higher, towards the blood where it’s lower due to the action of carbonic anhydrase.

Answer:

a. 211.7

Explanation:

Iron Pyrite reacts with Oxygen to produce Iron (II) Oxide and Sulphur (IV) Oxide.

The equation is as follows:

4FeS₂₍s₎ + 11O₂₍g₎ → 2Fe₂O₃₍s₎ + 8SO₂₍g₎

From the equation, 4 moles of FeS₂ produce 8 moles of SO₂.

Therefore the reaction ratio is 4:8 or 1:2

198.20 grams of FeS₂ into moles is calculated as follows:

Moles= Mass/RMM

RMM of FeS₂ is 119.9750g/mol.

Number of moles = 198.20/119.9750g/mol

=1.652 moles of FeS₂

The reaction ratio of FeS₂ to SO₂ produced is 1:2

Thus SO₂ produced = 1.652 moles×2/1=3.304 moles

The mass of SO₂ produced =Moles ×RMM

=3.304 moles ×64.0638 g/mol

=211.667 grams

=211.7g

Answer:

B,D,A,C,E

Explanation:

The first five steps of glycolysis are explained below:

Step -1 :The food we eat contains glucose which is converted to glucose-6-phosphate in the presence of enzyme hexokinase/ glucokinase. One ATP molecule is consumed in this step.

Step-2: Glucose-6- phosphate is converted to fructose-6- phosphate by the action of enzyme Phosphoglucose isomerase.

Step-3: Fructose-6- phosphate is converted to fructose-1,6-biphosphate in the presence of enzyme phosphofructokinase-1 (PFK-1) . One more ATP molecule is consumed in this step.

Step-4: Fructose 1,6-bisphosphate in the presence of fructose-bisphosphate aldolase is converted to D-glyceraldehyde 3-phosphate (GADP) and dihydroxyacetone phosphate (DHAP)

Step-5: Dihydroxyacetone phosphate (DHAP) in the presence of triosephosphate isomerase (TPI)  is converted to D-glyceraldehyde 3-phosphate (GADP).

Hence, the order it follows is:

B. hexokinase / glucokinase

D. Phosphoglucoisomerase

A. Phosphofructokinase-1 (PFK-1)

C. fructose bisphosphate aldolase

E. triose phosphate isomerase (TPI)

The trend is : B,D,A,C,E

The correct sequence of enzymes for the first five steps of glycolysis is: hexokinase/glucokinase, phosphoglucoisomerase, phosphofructokinase-1, fructose bisphosphate aldolase, and triose phosphate isomerase. This corresponds to answer choice B, D, A, C, E.

In the first step of glycolysis, hexokinase/glucokinase (B) phosphorylates glucose to produce glucose-6-phosphate. This molecule is then converted into fructose-6-phosphate by the enzyme phosphoglucoisomerase (D). The enzyme phosphofructokinase-1 (A) then phosphorylates fructose-6-phosphate to create fructose-1,6-bisphosphate. Fructose bisphosphate aldolase (C) breaks down fructose-1,6-bisphosphate into two three-carbon molecules: glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. Lastly, triose phosphate isomerase (E) converts dihydroxyacetone phosphate into a second glyceraldehyde-3-phosphate molecule.

So the correct order of the enzymes for the first five steps of glycolysis is: hexokinase/glucokinase, phosphoglucoisomerase, phosphofructokinase-1, fructose bisphosphate aldolase, and triose phosphate isomerase. This corresponds to the answer choice B, D, A, C, E.

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Answer: The temperature of the unknown sample is 64.65 °C

Explanation:

To calculate the temperature of the unknown sample, we use the following equation:

[tex]T=\frac{(V-V_1)}{(V_2-V_1)}\times (T_2-T_1)+T_1[/tex]

where,

T = temperature of the unknown sample = ?

V = thermistor reading of the unknown sample = 116 mV

[tex]T_1[/tex] = melting point of ice = 0°C

[tex]V_1[/tex] = thermistor reading of ice = -45 mV

[tex]T_1[/tex] = boiling point of water = 100°C

[tex]V_1[/tex] = thermistor reading of water = 204 mV

Putting values in above equation, we get:

[tex]T=\frac{(116-(-45))}{(204-(-45))}\times (100-0)+0\\\\T=64.65^oC[/tex]

Hence, the temperature of the unknown sample is 64.65 °C

The temperature of the unknown sample in C° is approximately 45.00°C.

To find the temperature of the unknown sample, we first need to establish a relationship between the voltage read by the thermistor and the temperature in degrees Celsius. We have two calibration points: ice water and boiling water, which correspond to 0°C and 100°C, respectively.

Let's denote the voltage read by the thermistor as \( V \) and the temperature as \( T \). We can then set up two equations based on the calibration points:

1. For ice water (0°C), the thermistor reads -45 mV:

[tex]\[ V_{ice} = -45 \text{ mV} \] \[ T_{ice} = 0°C \][/tex]

2. For boiling water (100°C), the thermistor reads 204 mV:

[tex]\[ V_{boiling} = 204 \text{ mV} \] \[ T_{boiling} = 100°C \][/tex]

We can assume a linear relationship between voltage and temperature for the thermistor, which allows us to use a simple linear interpolation formula:

[tex]\[ T = T_{ice} + \frac{(V - V_{ice}) \times (T_{boiling} - T_{ice})}{V_{boiling} - V_{ice}} \][/tex]

Now, we need to find the temperature \( T \) when the thermistor reads 116 mV for the unknown sample:

[tex]\[ T = 0°C + \frac{(116 \text{ mV} - (-45 \text{ mV})) \times (100°C - 0°C)}{204 \text{ mV} - (-45 \text{ mV})} \] \[ T = 0°C + \frac{(116 \text{ mV} + 45 \text{ mV}) \times 100°C}{204 \text{ mV} + 45 \text{ mV}} \] \[ T = 0°C + \frac{161 \text{ mV} \times 100°C}{249 \text{ mV}} \] \[ T = 0°C + \frac{161}{2.49} \times 100°C \] \[ T = 0°C + 64.6586345 \times 100°C \] \[ T = 64.6586345°C \][/tex]

Rounding to two decimal places, the temperature of the unknown sample is approximately 45.00°C.

Answer:

Which species of beetles are most closely related.

Explanation:

Molecular clocks are often used to determine where species diverge. This helps scientists determine the different mutations that had occurred to cause the separation of species. It can help find common ancestors within different species, so it can also determine how closely related species are.

Answer:

Which species of beetles are most closely related.

Explanation:

Final answer:

The average rate of decomposition of N2O5 over each time interval was calculated using changes in concentration over time, resulting in rates of 0.00123 M/s, 0.00105 M/s, and 0.00085 M/s for the respective intervals of 0-195 s, 195-556 s, and 556-825 s.

Explanation:

The average rate of a reaction is calculated by the change in concentration of a reactant or a product over a certain time period. For the decomposition of N2O5, the average rate over each time interval can be found using the formula: rate = -(Δ[N2O5])/(Δt), where Δ represents the change in concentration or time.

For the interval from 0 s to 195 s, the average rate is:
rate = - (1.86 M - 2.10 M) / (195 s - 0 s) = - (-0.24 M) / 195 s = 0.00123 M/s

For the interval from 195 s to 556 s, the average rate is:
rate = - (1.48 M - 1.86 M) / (556 s - 195 s) = - (-0.38 M) / 361 s = 0.00105 M/s

For the interval from 556 s to 825 s, the average rate is:
rate = - (1.25 M - 1.48 M) / (825 s - 556 s) = - (-0.23 M) / 269 s = 0.00085 M/s

Answer : The rate order of reaction is, second order reaction.

Explanation :

Rate of reaction : It is defined as the rate of change in concentration of reactant or product with respect to time.

Order of reaction : It is defined as the sum of the exponents or powers to which the molar concentration in the rate law equation are raised to express the observed rate of reaction.

As per question the reaction will be :

[tex]A+B\rightarrow C+D[/tex]

The given rate expression is,

[tex]Rate=k[A][B][/tex]

From this expression we conclude that the power of concentration of reactant A and B are 1, 1.

The sum of power of concentration of reactant A and B = 1 + 1 = 2

That means it is a second order reaction.

Hence, the rate order of reaction is, second order reaction.

Answer:

second - order

Explanation:

Answer: 8 alpha particles

Explanation:-

Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.

General representation of alpha decay :

[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]

[tex]_{92}^{238}\textrm{U}\rightarrow _{82}^{26}\textrm{Pb}+_2^4\textrm{He}[/tex]

As the mass should remain same after the decay, we can use:

238=206+(4x)

Solving for x, we get:

x= 8.

Thus 8 alpha particles are emitted in the series of radioactive decay events from a U-238 nucleus to a Pb-206 nucleus.

Answer:

D) blood glucose levels are low

Explanation:

When glucose levels are low, glucagon levels increase. The glucagon will then bind to receptors on the adipose cells' surface, thus setting off further reactions which culminates in fatty acids being released from the cells. They will then flow through the circulatory system, where they will either bind to a protein in blood or be used by muscle tissue for energy.

Answer:

1. [H₃O⁺] = 2.0 x 10⁻⁹ M.

   [OH⁻] = 3.55 x 10⁻⁶ M.

  The solution is basic.

2. [H₃O⁺] = 3.16 x 10⁻⁴ M.

   [OH⁻] = 3.16 x 10⁻¹¹  M.

  The solution is acidic.

3. [OH⁻] = 2.72 x 10⁻⁷ M.

   pH = 7.435.

   The solution is basic.

4. [OH⁻] = 9.89 x 10⁻³ M.

   pH = 2.0.

   The solution is acidic.

5. [H₃O⁺] = 1.82 x 10⁻⁵ M.

   pH = 4.74.

  The solution is acidic.

6.

[H₃O⁺] = 1.176 x 10⁻¹³ M.

   pH = 12.93.

   The solution is basic.

7. The solution is basic.

8. The solution is acidic.

9. The solution is acidic.

10. The solution is neutral.

Explanation:

pH = - log[H⁺],

pOH = - log[OH⁻],

Kw = [H⁺][OH⁻] = 10⁻¹⁴.

pH scale is a scale from 0 to 14, from which we can determine the nature of the solution:

1. Given pH = 8.55, Find: [H₃O⁺] and [OH⁻], Is this acidic, basic or neutral?

∵ pH = - log[H₃O⁺]

∴ 8.55 =  - log[H₃O⁺]

∴ [H₃O⁺] = 2.0 x 10⁻⁹ M.

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(2.0 x 10⁻⁹ M) = 3.55 x 10⁻⁶ M.

∵ pH = 8.55 > 7,

∴ The solution is basic.

2. Given pH = 3.50, Find: [H₃O⁺] and [OH⁻], Is this acidic, basic or neutral?

∵ pH = - log[H₃O⁺]

∴ 3.50 =  - log[H₃O⁺]

∴ [H₃O⁺] = 3.16 x 10⁻⁴ M.

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(3.16 x 10⁻¹⁴ M) = 3.16 x 10⁻¹¹ M.

∵ pH = 3.50 < 7,

∴ The solution is acidic.

3. Given [H₃O⁺] = 3.67 x 10⁻⁸ M, Find: [OH⁻] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(3.67 x 10⁻⁸ M) = 2.72 x 10⁻⁷ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(3.67 x 10⁻⁸ M) = 7.435.

∵ pH = 7.435 > 7,

∴ The solution is basic.

4. Given [H₃O⁺] = 9.89 x 10⁻³ M, Find: [OH⁻] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(9.89 x 10⁻³ M) = 9.89 x 10⁻³ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(9.89 x 10⁻³ M) = 2.0.

∵ pH = 2.0 < 7,

∴ The solution is acidic.

5. Given [OH⁻] = 5.5 x 10⁻¹⁰ M, Find: [H₃O⁺] and pH, Is this acidic, basic or neutral?

 ∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(5.5 x 10⁻¹⁰ M) = 1.82 x 10⁻⁵ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.82 x 10⁻⁵ M) = 4.74.

∵ pH = 4.74 < 7,

∴ The solution is acidic.

6. Given [OH⁻] = 8.5 x 10⁻² M, Find: [H₃O⁺] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(8.5 x 10⁻² M) = 1.176 x 10⁻¹³ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.176 x 10⁻¹³ M) = 12.93.

∵ pH = 12.93 > 7,

∴ The solution is basic.

7. Given [OH⁻] = 3.75 x 10⁻⁵ M, Is this acidic, basic or neutral?  How do you know?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.75 x 10⁻⁵ M) = 2.67 x 10⁻¹⁰ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(2.67 x 10⁻¹⁰ M) = 9.57.

∵ pH = 9.57 > 7,

∴ The solution is basic.

8. Given [H₃O⁺] = 3.75 x 10⁻³ M, Is this acidic, basic or neutral?  How do you know?

∵ pH = - log[H₃O⁺]

∴ pH = - log(3.75 x 10⁻³ M) = 2.43.

∵ pH = 2.43 < 7,

∴ The solution is acidic.

9. Given pH = 6.75,  Is this acidic, basic or neutral?  How do you know?

∵ pH = 6.75 < 7,

∴ The solution is acidic.

10. Given [H₃O⁺] = 1.00 x 10⁻⁷ M, Is this acidic, basic or neutral?  How do you know?

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.0 x 10⁻⁷ M) = 7.0.

∵ pH = 7.0,

∴ The solution is neutral.

Answer:

4.51 kJ of heat is liberated to the surroundings when 1 gram of zinc sulfide is roasted.

Explanation:

From the reaction and its associated enthalpy change, we know that the heat associated with 2 moles of zinc sulfide is -879 kJ.

Data: 1 gram of zinc sulfide

moles of zinc sulfide = mass of zinc sulfide / Molecular weight of zinc sulfide

moles = 1 g/ (97.474 g/mol) = 0.01 mol

The following proportion must be satisfied:

2 moles / 0.01 mol  = -879 kJ / x kJ

x = -879*0.01/2 = -4.395 kJ

The negative sign means that the heat is liberated to the surroundings.

Final answer:

The heat associated with roasting 1 gram of zinc sulfide can be calculated using the given information. For 1 gram of ZnS, the heat would be -4.48 kJ.

Explanation:

The heat associated with roasting 1 gram of zinc sulfide can be calculated using the given information. The equation for the reaction is: 2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g). The enthalpy change (ΔH) for this reaction is -879 kJ. We need to find the heat associated with roasting 1 gram of zinc sulfide, so we can use the molar mass of ZnS to convert the mass from grams to moles. The molar mass of ZnS is approximately 97.45 g/mol. Therefore, 1 gram of ZnS is equal to 0.0103 moles of ZnS. To calculate the heat, we can use the stoichiometric coefficients from the balanced equation. For every 2 moles of ZnS, we have an enthalpy change of -879 kJ. Therefore, for 0.0103 moles of ZnS, the heat associated with roasting would be (0.0103/2) x -879 kJ = -4.48 kJ.

if              1 g is equal to 100 cg

then  0.55 g are equal to X cg

X = (0.55 × 100 ) / 1 = 55 cg

The density of the object is 55 cg/L.

Answer : The density in cg/L is, 55000 cg/L

Explanation :

Density : It is defined as the mass of a substance contained per unit volume.

The conversion used from gram to centigram is:

1 gram = 100 centigram

The conversion used from milliliter to liter is:

1 mL = 0.001 L

So,

1 g/mL = [tex]\frac{100}{0.001}cg/L=100000cg/L[/tex]

As we are given the density 0.55 g/mL. Now we have to determine the density in cg/L.

As, 1 g/mL = 100000 cg/L

So, 0.55 g/mL = [tex]\frac{0.55g/mL}{1g/mL}\times 100000cg/L=55000cg/L[/tex]

Therefore, the density in cg/L is, 55000 cg/L

To be able to compare the result with other experiments it has to be reported in moles.

number of moles = mass / molecular weight

number of moles of Mg(H₂PO₄)₂ = 600 / 218 = 2.75 moles

Answer: 2.75 moles of magnesium dihydrogen phosphate

Explanation:   We have been given 600 gm of Mg(H2PO4)2 .

The molecular mass of Mg(H2PO4)2 is 218 gm.

As it is given that the answer should be in moles so that it can become comparable with other experiments, thus number of moles can be calculated by dividing the given mass by molecular mass of the given salt.

number of moles (n) = given mass(m) / molecular mass of the salt (M)

n= 600 gm  / 218 gm = 2.75

Thus 2.75 moles of magnesium dihydrogen phosphate(Mg(H2PO4)2) will be recorded.