Im really confused and select all that apply questions scare me.

Answer:

[tex]M_{base}=0.709M[/tex]

Explanation:

Hello,

In this case, since the reaction between potassium hydroxide and nitric acid is:

[tex]KOH+HNO_3\rightarrow KNO_3+H_2O[/tex]

We can see a 1:1 mole ratio between the acid and base, therefore, for the titration analysis, we find the following equality at the equivalence point:

[tex]n_{acid}=n_{base}[/tex]

That in terms of molarities and volumes is:

[tex]M_{acid}V_{acid}=M_{base}V_{base}[/tex]

Thus, solving the molarity of the base (KOH), we obtain:

[tex]M_{base}=\frac{M_{acid}V_{acid}}{V_{base}} =\frac{0.498M*42.7mL}{30.0mL}\\ \\M_{base}=0.709M[/tex]

Regards.

Answer:

d. Oxidation and reduction

Explanation:

For this question we have to remember the definition of each type of reaction:

-) Hydrogenation

In this reaction, we have the addition of hydrogen to a molecule. Usually, an alkene or alkyne. In the example, molecular hydrogen is added to a double bond to produce an alkane.

-) Alkylation

In this reaction, we have the addition of a chain of carbon to another molecule. In the example, an ethyl group is added to a benzene ring.

-) Hydrolysis

In this reaction, we have the breaking of a bond by the action of water. In the example, a water molecule can break the C-O bond in the ester molecule.

-) Halogenation

In this reaction, we have the addition of a halogen (atoms on the VIIIA group). In the example, "Cl" is added to the butene.

-) Ammoniation

In this reaction, we have the addition of the ammonium ion ([tex]NH_4^+[/tex]). In the example, the ammonium ion is added to an acid.

-) Oxidation and reduction

In this reaction, we have opposite reactions. The oxidation is the loss of electrons and the reduction is the gain of electrons. For example:

[tex]Ag^+~+~e^-~->~Ag[/tex] Reduction

[tex]Al~->~Al^+^3~+~3e^-[/tex] Oxidation

Answer:

[tex]Ksp=2.59x10^{-3}[/tex]

Explanation:

Hello,

In this case, given the 0.0990 moles of the salt are soluble in 1.00 L of water only, we can infer that the molar solubility is 0.099 M. Next, since the dissociation of the salt is:

[tex]AB_3\rightleftharpoons A^{3+}+3B^-[/tex]

The concentrations of the A and B ions in the solution are:

[tex][A]=0.099 \frac{molAB_3}{L}*\frac{1molA}{1molAB_3} =0.0099M[/tex]

[tex][B]=0.099 \frac{molAB_3}{L}*\frac{3molB}{1molAB_3} =0.000.297M[/tex]

Then, as the solubility product is defined as:

[tex]Ksp=[A][B]^3[/tex]

Due to the given dissociation, it turns out:

[tex]Ksp=[0.099M][0.297M]^3\\\\Ksp=2.59x10^{-3}[/tex]

Regards.

Answer:

72.8 % (But verify explanation).

Explanation:

Hello,

In this case, with the following obtained results, the percent error is computed as follows:

Volume of vinegar= 7.0 mL

Volume of NaOH= (7+6.6+6.4)/3= 6.7 mL

Used concentration of NaOH= 1.5M

Concentration of acetic acid= (concentration of NaOH*volume of NaOH)/volume of vinegar= (6.7mL*1.5M)/7.0M= 1.44M

Assuming we have 100 mL (0.100L) of vinegar, moles of acetic acid in vinegar = 1.44M x 0.100 L= 0.144 mol

Mass of acetic acid in 100g of vinegar = 0.144 mol x 60.0g/mol= 8.64 g

% of acetic acid in vinegar=8.64 %

% error in percentage of acetic acid = [(8.64% - 5.0%)/5.0] x 100=72.8 %

Clearly, this result depend on your own measurements, anyway, you can change any value wherever you need it.

Regards.

Answer:

The answer is a.

Explanation:

Most of the costs associated with using renewable resources are due to overuse of the resources.

Most of the costs associated with using renewable resources are due to overuse of resources.

Renewable resources are those resources which will be generated naturally and continously from the nature and these are also inexhaustible means non ended.

As from the definition it is clear that we can reuse or will use again and again these types of resources, that's why cost associated with these renewable resources are high.

Hence, overuse of resouces is one of the reason.

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Answer:

A - right shift

B - no shift

C - right shift

Explanation:

According to Le Chatelier's principle, when a reaction is in equilibrium and one of the factors affecting the rate of reaction is introduced, the equilibrium will shift so as to annul the effects of the constraint.

In this case, decreasing the volume of the reaction's container is equivalent to increasing the pressure of the reaction. When pressure is increased, the reaction will shift towards the side with a lower number of moles.

In A, the total number of moles on the left-hand side of the reaction is two while it is one on the right-hand side. An increase in pressure will, therefore, see the equilibrium shifting to the right-hand side.

In B, the total number of moles on both the right and the left-hand side is two each. An increase in the pressure will have no effect on the equilibrium.

In C, the total number of moles on the left-hand side is two while it is one on the right-hand side. Hence, an increase in the pressure of the reaction will cause a shift in the equilibrium to the right.

Answer:

Companies know that people will be willing to spend more to get an in-demand product.

Explanation:

When a product is really in demand, many customers are willing to part with more money order to purchase the product, as a result of that, many companies may take advantage of the increasing demand for the product to hike it's price.

Hence, the increase in price may not really have a negative impact on the quantity demanded because the demand for the product is high and customers are willing to spend more money in order to purchase an in-demand product, hence the answer above.

Prices increase when demand is high because companies know that people will be willing to spend more to get in-demand products.

Prices generally increase with higher demand for goods because the higher demand creates pressure for the supply to meet up.

Manufacturing companies can either increase their production to meet up with demand at the same price or capitalize on the situation to make more money by increasing the price without increasing the supply.

Since there is a buying pressure on the product in the market already, people would still be open to buying even at higher prices.

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Answer: The calculated molar enthalpy change of reaction for his second trial was -108 kJ.

Explanation:-

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

[tex]\text{no of moles}={\text{Molarity}\times {\text{Volume in L}}[/tex]

Thus [tex]\text{no of moles}of HCl={1.0M}\times {0.05L}=0.05moles[/tex]

Thus [tex]\text{no of moles}of NaOH={1.0M}\times {0.05L}=0.05moles[/tex]

[tex]HCl(aq)+NaOH(aq)\rightarrow NaCl(aq)+H_2O(l)[/tex]

Given for second trial:

[tex]\text{no of moles}of HCl={1.0M}\times {0.1L}=0.1moles[/tex]

[tex]\text{no of moles}of NaOH={1.0M}\times {0.1L}=0.1moles[/tex]

0.05 moles of [tex]HCl[/tex] reacts with 0.05 moles of [tex]NaOH[/tex] to release  heat = 54 kJ

0.1 moles of [tex]HCl[/tex] reacts with 0.05 moles of [tex]NaOH[/tex] to release  heat  =[tex]\frac{54}{0.05}\times 0.1=108kJ[/tex]

Thus calculated molar enthalpy change of reaction for his second trial was -108 kJ.

Answer:

Lone pairs cause more repulsion than bond pairs

Explanation:

A lone pair takes up more space around the central atom than bond pairs of electrons. This is because, a lone pair is attracted to only one nucleus while bond pairs are attracted to two nuclei.

Hence the repulsion between lone pairs is far greater than the repulsion between bond pairs or repulsion between a lone pair and a bond pair. The presence of a lone pair therefore distorts a molecule away from the ideal shape predicted on the basis of the valence shell electron pair repulsion theory.

Lone pairs are found to decrease the observed bond angles in a molecule.

Answer:

c

Explanation:

How many moles of gold are equivalent to 1.204 × 1024 atoms?

0.2

0.5

2

5

C) 2 Is the correct answer, I took the test and it was correct.

According to the concept of Avogadro's number, there are 2 moles of gold which are equivalent to 1.204×10²⁴ atoms.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.Number of moles=number of atoms/Avogadro's number=1.204×10²⁴ /6.023×10²³=1.999≅2

Thus, there are 2 moles of gold which are equivalent to 1.204×10²⁴ atoms.

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Answer:

[tex]128~ATP[/tex]

Explanation:

The metabolic pathway by which energy can be obtained from a fatty acid is called "beta-oxidation". In this route, acetyl-Coa is produced by removing 2 carbons from the fatty acid for each acetyl-Coa produced. In other words, for each round, 1 acetyl Coa is produced and for each round 2 carbons are removed from the initial fatty acid. Therefore, the first step is to calculate the number of rounds that will take place for an 18-carbon fatty acid using the following equation:

[tex]Number~of~Rounds=\frac{n}{2}-1[/tex]

Where "n" is the number of carbons, in this case "18", so:

[tex]Number~of~Rounds=\frac{18}{2}-1~=~8[/tex]

We also have to calculate the amount of Acetyl-Coa produced:

[tex]Number~of~Acetyl-Coa=\frac{18}{2}~=~9[/tex]

Now, we have to keep in mind that in each round in the beta-oxidation we will have the production of 1 [tex]FADH_2[/tex] and 1 [tex]NADH[/tex]. So, if we have 8 rounds we will have 8 [tex]FADH_2[/tex] and 8 [tex]NADH[/tex].

Finally, for the total calculation of ATP. We have to remember the yield for each compound:

-) [tex]1~FADH_2~=~2~ATP[/tex]

-) [tex]1~NADH~=~3~ATP[/tex]

-) [tex]Acetyl~CoA~=~10~ATP[/tex]

Now we can do the total calculation:

[tex](8*2)~+~(8*3)~+~(9*10)=130~ATP[/tex]

We have to subtract  "2 ATP" molecules that correspond to the activation of the fatty acid, so:

[tex]130-2=128~ATP[/tex]

In total, we will have 128 ATP.

I hope it helps!

Answer:The concentration of the unknown HNO3 solution = 0.01809 M

Explanation:

For the acid-base reaction,  HNO3 + NaOH-----> NaN03 + H20

we have that

C1 V1 = C2 V2

Where ,

C1 = concentration of HNO3=?

V1 = volume of HNO3 = 25.00 mL,

V2 = volume of NaOH = 22.62 mL,  

C2 = concentration of NaOH = 0.02000 M

Therefore ,

25.00 mL x C1 = 22.62 mL x 0.02000 M    

 = (22.62 mL / 25.00 mL) x 0.02000 M = 0.01809 M

The concentration of the unknown HNO3 solution = 0.01809 M

Answer:

0.9718M

Explanation:

Rate constant, k =  0.255 M-1s-1

time, t = 8.00 s

Initial concentration, [A]o = 1.33 M

Final concentration, [A] = ?

These quantities are represented by the equation;

1 / [A] = 1 / [A]o + kt

1 / [A] = 1 /1.33 + (0.255 * 8)

1 / [A] = 0.7519 + 2.04

[A] = 1 / 2.7919 = 0.3582 M

How much of NO2 decomposed is obtained from the change in concentration;

Change in concentration = Initial - Final

Change = 1.33 - 0.3582 = 0.9718M

Answer:

²³⁴₉₀Th --> ²³⁴₉₁Pa + ⁰₋₁e

Explanation:

thorium-234 = ²³⁴₉₀Th

beta decay = ⁰₋₁e

protactinium-234 = ²³⁴₉₁Pa

The balanced nuclear equation is given as;

²³⁴₉₀Th --> ²³⁴₉₁Pa + ⁰₋₁e

Answer:Liquid

Explanation:

Answer:

Number of mole in Oxygen = 2.24 mol

Explanation:

Given:

Amount of carbon dioxide (CO₂) = 49.2 gram

Find:

Number of moles in Oxygen

Computation:

Molecular weight of CO₂ = 44 gram (Approx)

Number of mole in CO₂ = 49.2 / 44

Number of mole in CO₂ = 1.11818182 mol

CO₂ has 2 mole of Oxygen,

So,

Number of mole in Oxygen = 2 × 1.11818182

Number of mole in Oxygen = 2.23636364

Number of mole in Oxygen = 2.24 mol

Answer:

Molar solubility of AgBr = 51.33 × 10⁻¹³

Explanation:

Given:

Amount of NaBr = 0.150 M

Ksp (AgBr) = 7.7 × 10⁻¹³

Find:

Molar solubility of AgBr

Computation:

Molar solubility of AgBr = Ksp (AgBr) / Amount of NaBr

Molar solubility of AgBr = 7.7 × 10⁻¹³ / 0.150

Molar solubility of AgBr = 51.33 × 10⁻¹³

When The Molar solubility of AgBr is = 51.33 × 10⁻¹³

Given as per question:

The Amount of NaBr is = 0.150 M

Then Ksp (AgBr) is = 7.7 × 10⁻¹³

Now we Find:

The Molar solubility of AgBr

The we Computation is:

The Molar solubility of AgBr is = Ksp (AgBr) / Amount of NaBr

After that Molar solubility of AgBr is = 7.7 × 10⁻¹³ / 0.150

Therefore, Molar solubility of AgBr is = 51.33 × 10⁻¹³

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Answer:

"Both signs are possible" is the correct choice.

Explanation:

As such that when both signals could have been the enthalpy change.

If the dissolution of borax in water is spontaneous, so the change in enthalpy should be negative.

Enthalpy of the reaction tells about the total amount of energy released or absorbed during any chemical reaction.

And for the spontaneous reaction, value of standard Gibb's free energy change of the reaction should be negative and formula will be represented as:
ΔG = ΔH - TΔS, where

ΔH = change in enthalpy

For the spontaneous reaction, value of enthalpy should be negative so that we get the negative value of ΔG.

Hence change in enthalpy should be negative.

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Answer:

The frequency of the photon is 7.41*10¹⁶ Hz

Explanation:

Planck states that light is made up of photons, whose energy is directly proportional to the frequency of radiation, according to a constant of proportionality, h, which is called Planck's constant. This is expressed by:

E = h*v

where E is the energy, h the Planck constant (whose value is 6.63*10⁻³⁴ J.s) and v the frequency (Hz or s⁻¹).

So the frequency will be:

[tex]v=\frac{E}{h}[/tex]

Being E= 4.91*10⁻¹⁷ J and replacing:

[tex]v=\frac{4.91*10^{-17} J}{6.63*10^{-34} J.s}[/tex]

You can get:

v= 7.41*10¹⁶ [tex]\frac{1}{s}[/tex]= 7.41*10¹⁶ Hz

The frequency of the photon is 7.41*10¹⁶ Hz

Answer:

At equilibrium, the cell voltage is zero volts.

Explanation:

During an electrochemical reaction, electrical energy is produced. The reaction continues to produce electrical energy until a point is reached in which the reaction attains equilibrium.

Before the reaction attains equilibrium, the cell voltage continues to decrease progressively as the reaction progresses. At equilibrium, the cell voltage becomes zero and the read out voltmeter records 0 V.

Hence, at equilibrium, the cell voltage is zero volts.

Answer:

323 K

Explanation:

Since it is in equilibrium, we get  Δ=0=Δ−Δ

                                                      Δ=Δ

                                                      =ΔΔ

Now we solve for T

T = ( -28.4 kJ) / (-87.9 J/K * 1kJ/1000J) = 323 K

Based on the fact that there is very little change in value with temperature, the temperature that the reaction changes to spontaneous would be 323.1K.

This can be found as:

ΔH∘ = Temperature x  ΔS∘

Temperture = ΔH∘ /  ΔS∘

Solving gives:

= - 28.4 / - 87.9

= 323.1 k

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Answer:

THE ENTHALPY CHANGE IN KJ/MOLE IS +114 KJ/MOLE.

Explanation:

Heat = mass * specific heat capacity * temperature rise

Total volume = 100 + 50 = 150 mL

Total mass = density * volume

Total mass = 1 * 150 mL = 150 g

So therefore, the heat evolved during the reaction is:

Heat = 150 * 4.18 * ( 31.4 - 22.3)

Heat = 150 * 4.18 * 9.1

Heat = 5705.7 J

Equation for the reaction:

2 NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2 H2O(l)  

From the equation, 2 moles of NaOH reacts with 1 mole of H2SO4 to produce 1 mole of Na2SO4 and 2 moles of water

50 mL of 1 M of H2SO4 contains

50 * 1 / 1000 mole of acid

= 0.05 mole of acid

The production of 1 mole of water evolved 5705.7 J of heat and hence the enthalpy changein kJ per mole will be:

0.05 mole of H2SO4 produces 5705.7 J of heat

1 mole of H2SO4 will produce 5705.7 / 0.05 J

= 114,114 J / mole

In kj/mole = 114 kJ/mole.

Hence, the enthalpy change of the reaction in kJ /mole is +114 kJ/mole.

Answer:

1 L

Explanation:

ppm means parts per million. Generally the relationship between mass and litre is given as;

1 ppm = 1 mg/L

This means that 1 ppm is equivalent to 1 mg of a substance dissolved in 1 L of water.

Answer:

[tex]\large \boxed{1.10 \times 10^{-3}\text{ mol/L}}[/tex]

Explanation:

1. Concentration of SO₄²⁻

SrSO₄(s) ⇌ Sr²⁺(aq) +SO₄²⁻(aq); Ksp = 3.44 × 10⁻⁷

                   0.0150          x

[tex]K_{sp} =\text{[Sr$^{2+}$][SO$_{4}^{2-}$]} = 0.0150x = 3.44 \times 10^{-7}\\x = \dfrac{3.44 \times 10^{-7}}{0.0150} = \mathbf{2.293 \times 10^{-5}} \textbf{ mol/L}[/tex]

2. Concentration of Pb²⁺

PbSO₄(s) ⇌ Pb²⁺(aq) + SO₄²⁻(aq); Ksp = 2.53 × 10⁻⁸

                        x          2.293 × 10⁻⁵

[tex]K_{sp} =\text{[Pb$^{2+}$][SO$_{4}^{2-}$]} = x \times 2.293 \times 10^{-5} = 2.53 \times 10^{-8}\\\\x = \dfrac{2.53 \times 10^{-8}}{2.293 \times 10^{-5}} = \mathbf{1.10 \times 10^{-3}} \textbf{ mol/L}\\\\\text{The concentration of Pb$^{2+}$ is $\large \boxed{\mathbf{1.10 \times 10^{-3}}\textbf{ mol/L}}$}[/tex]

Answer:

1. metals

2. atom

3. homogeneous

4. compounds

5. lustrous

6. saturated

7. colloidal

8. homogeneous

Explanation:

Answer:

A. Ka = [CO2] / [C] [O2]^1/2

B. Kb = [CO2] / [CO] [O2]^1/2

Explanation:

Equilibrium constant is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.

Now, we shall obtain the expression for the equilibrium constant for the reaction as follow:

A. Determination of the expression for equilibrium constant Ka.

This is illustrated below:

C(s) + 1/2 O2(g) <==> CO(g)

Ka = [CO2] / [C] [O2]^1/2

B. Determination of the expression for equilibrium constant Kb.

This is illustrated below:

CO(g) + 1/2 O2(g) <==> CO2(g)

Kb = [CO2] / [CO] [O2]^1/2

Answer:

A. Rank the following substances in order of decreasing standard molar entropy (S∘).

Rank the gases from largest to smallest standard molar entropy

I2(g)>Br2(g)>Cl2(g)>F2(g)

B. Rank the gases from largest to smallest standard molar entropy. To rank items as equivalent, overlap them.

H2O2(g)>H2S(g) >H2O(g)

C. Rank the gases from largest to smallest standard molar entropy. To rank items as equivalent, overlap them.

C(s, amorphous) >C(s, graphite)>C(s, diamond)

Explanation:

Hello,

In this case, we can apply the following principles to explain the order:

- The greater the molar mass, the larger the standard molar entropy.

- The greater the molar mass and the structural complexity, the larger the standard molar entropy.

- The greater the structural complexity, the larger the standard molar entropy.

A. Rank the following substances in order of decreasing standard molar entropy (S∘).

Rank the gases from largest to smallest standard molar entropy

I2(g)>Br2(g)>Cl2(g)>F2(g)

This is due to the fact that the greater the molar mass, the larger the standard molar entropy.

B. Rank the gases from largest to smallest standard molar entropy. To rank items as equivalent, overlap them.

H2O2(g)>H2S(g) >H2O(g)

This is due to the fact that the greater the molar mass and the structural complexity, the larger the standard molar entropy as the hydrogen peroxide has four bonds and weights 34 g/mol as well as hydrogen sulfide that has two bonds only.

C. Rank the gases from largest to smallest standard molar entropy. To rank items as equivalent, overlap them.

C(s, amorphous) >C(s, graphite)>C(s, diamond)

Since the molecular complexity is greater in the amorphous carbon (messy arrangement), mid in the graphite and lower in the diamond (well organized).

Regards.

from

1moles=iatom

Mole=mass÷avogardos

Where

Avogadro's= 6.02×10²³

So moles = 65.0÷6.02×10²³

Atoms of zinc = 391.6 ×10²³

The number of atoms present in the given mass of Zinc that is 65.0gm is [tex]5.99\times10^{ 23}[/tex].

Atoms are the basic building blocks of matter. They are the smallest units of an element that retain the chemical properties of that element.

Now, to determine the number of atoms in a given number of moles, we can use Avogadro's number, which is approximately  [tex]6.022 \times10^{23}[/tex]atoms per mole.

First, we calculate the number of moles of zinc in 65.0g by dividing the given mass by the molar mass of zinc. The molar mass of zinc (Zn) is 65.38 g/mol.

Number of moles = Mass / Molar mass

Number of moles = 65.0g / 65.38 g/mol ≈ 0.9942 mol

Next, multiply the number of moles by Avogadro's number to find the number of atoms.

Number of atoms =[tex]Number of moles \times Avogadro's number[/tex]

Number of atoms = [tex]0.9942[/tex]mol × [tex]6.022 \times10^{23}[/tex] atoms/mol

Therefore, approximately [tex]5.99\times10^{ 23}[/tex] atoms are present in 65.0g of zinc.

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