The lava from a volcano can travel up to 100 km/hr if a village is located 3.6 mi from the volcano how many minutes will it take the lava to reach the village

Answer:

B, C

Explanation:

The atoms or ions with the valid Lewis dot structures are B and C.

In A;

The Lewis structure of the carbon is correct. Each of the four dots represent the four valence electrons.

The  nitrogen with one dot on top, left and to the bottom and has a charge of minus 3 is wrong. For it to have a charge of -3 it must have 8 lewis dots ( two on the top, right, bottom and to the left)

The nitrogen with four dots (on top, right, bottom and to the left) is wrong.

In B;

An oxygen has two dots on top and bottom and one dot to the left and to the right. This is correct , the 6 dots represent the valence electrons of oxygen.

In C;

A carbon has two dots on top, right, bottom and to the left and a charge of plus four. This is correct because the charge indicates that it has gained four extra electrons so its valence electrons is now 8.

In D;

An oxygen has two dots on top, left and to the bottom and a charge of minus 2. This is wrong because the lewis dots are incomplete. Two dots are missing.

Answer:

This is because Hydrogen peroxide must be acidic, thereby making hydrogen ions taking part in the reaction which act as reactant. It is important also to use H2SO4 because permanganate is a strong oxidizing agent and it cannot oxidize sulphuric acid if enough is added but it can oxidize chloride ions to chlorine if hydrochloric acid is used.

Explanation:

Hydrogen peroxide is used as a chemical agents in cleaning processes for chemical industries and semiconductor plants. In the hydrogen peroxide assay, sulphuric acid is used and the reaction is an exothermic reaction. This produce strong peroxysulphuric acid

Answer:

33Cl

Explanation:

The atomic mass of an element is made up of the proton and neutron.

chlorine has a constant number of 17 protons.

33-17 = 16

A soluble base is formed when sodium reacts with water.

When sodium reacts with water, it produces strongly alkalic sodium hydroxide which is also called caustic soda and hydrogen gas. In this chemical reaction, energy is absorbed which means it is an exothermic reaction so we can conclude that a soluble base is formed when sodium reacts with water.

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Answer:

1-Pentene

Explanation:

If we look at all the options listed, we will notice that the rate of reaction of bromine with each one differs significantly.

For 1-pentene, addition of bromine across the double bond is a relatively fast process. It is usually used as a test for unsaturation. Bromine water is easily decolorized by alkenes.

Cyclohexane, heptane are alkanes. They can only react with chlorine in the presence of sunlight. This is a substitution reaction. It does not occur easily. A certain quantum of light is required for the reaction to occur.

For benzene, bromine can only react with it by electrophilic substitution in which the benzene ring is retained. A Lewis acid is often required for the reaction to occur and it doesn't occur easily.

Answer:

1. The correct option is;

c. maintains charge balance in the cell

2. The correct option is;

c. +3.272 V

Explanation:

The aqueous solution in a galvanic cell is the electrolyte which is a ionic solution containing that permits the transfer of ions between the separated compartment of the galvanic cell such that the overall system is electrically neutral

Therefore, the aqueous solution maintains the charge balance in the cell

2. Here we have;

B₂ + 2e⁻ → 2B⁻ Ecell = 0.662 V

A⁺ + 1e⁻ → A Ecell = -1.305 V

Hence for the overall reaction, we have;

2A + B₂ → 2AB gives;

(0.662) - 2×(-1.305)  = +3.272 V.

Answer:

1) Human activities such as the combustion of fossil fuels, has increased the levels of greenhouse gases----  Chemical reaction.

2) At dew point, the water vapor begins to condense out of air----  Physical changes.

3)  Human activities, such as the combustion of fossil fuels, generate the aerosols----  Chemical reaction.

4) You observe hail when the temperatures are below the freezing point----  Physical changes.

5) Carbon dioxide is produced during respiration of plants, animals, fungi, and microorganisms-----  Chemical changes.

Answer:

A. Reversible reactions.

Explanation:

Reactions that undergo shifts in their equilibrium must be reversible reactions.

A reversible reaction is a chemical reaction that is capable of forming it's reactants back from the resulting formation of products. This simply means that, reversible reactions are chemical reactions that are in equilibrium because the forward and reverse path happens at the same rate.

For example, the reaction of hydrogen gas [tex]H_{2}[/tex] and iodine gas [tex]I_{2}[/tex] to form a chemical compound called hydrogen Iodide [tex]HI[/tex] is a reversible chemical reaction.

Forward reaction:

[tex]H_{2} + I_{2} ----> 2HI[/tex]

Reverse reaction:

[tex]2HI----> H_{2} + I_{2}[/tex]

A reversible reaction is denoted with a double arrow.

Also, reversible chemical reactions are controlled by the Le Chatelier's principle.

Answer:

Explanation:

O₂(g) + 2F₂(g) ↔ 2F₂(g)

Stabdard ΔG values are

[tex]\Delta G_f[F_2O]=41.9kJ/mol =41900J/mol[/tex]

[tex]\Delta G_f[O_2]=0\\\\ \Delta G_f[F_2]=0[/tex]

[tex]\Delta G^0=\sum \Delta G^\circ (products)- \sum \Delta G ^\circ (reactants)[/tex]

[tex]\Delta G^\circ = [2 \times 41900]-0\\\\=83800J/mol[/tex]

Now,

[tex]\Delta G^\circ =-RTInK[/tex]

Given T = 100°C

= 100+ 273.15 = 373.15K

R = 8.314J/k / mol

so,

83800 = -8.314 * 373.15 * InK

InK = -27.0116

K = 1.858 * 10⁻¹²

Answer:

884.8 mL

Explanation:

If we have STP condition (Standard temperature and pressure), we will have the following relationship:

[tex]1~mol=22.4~L[/tex] or [tex]1~mol=22400~mL[/tex]. With this in mind we can do the conversion:

[tex]0.0395~mol\frac{22400~mL}{1~mol}=884.8~mL[/tex]

In the 0.0395 mol of fluorine gas, we will have 884.8 mL of gas at STP conditions.

Answer:

pH = 7.1581

Explanation:

The equilibrium of NaHSO₃ with Na₂SO₃ is:

HSO₃⁻ ⇄ SO₃²⁻ + H⁺

Where K of equilibrium is the Ka2: 6.5x10⁻⁸

HSO₃⁺ reacts with NaOH, thus:

HSO₃⁻ + NaOH → SO₃²⁻ + H₂O + Na⁺

As the buffer is of 1.0L, initial moles of HSO₃⁻ and SO₃²⁻ are:

HSO₃⁻: 0.252 moles

SO₃²⁻: 0.139 moles

Based on the reaction of NaOH, moles added of NaOH are subtracting moles of HSO₃⁻ and producing SO₃²⁻. The moles added are:

0.0500L ₓ (1mol /L): 0.050 moles of NaOH.

Thus, final moles of both compounds are:

HSO₃⁻: 0.252 moles - 0.050 moles = 0.202 moles

SO₃²⁻: 0.139 moles + 0.050 moles = 0.189 moles

Using H-H equation for the HSO₃⁻ // SO₃²⁻ buffer:

pH = pka + log [SO₃²⁻] / [HSO₃⁻]

Where pKa is - log Ka = 7.187

Replacing:

pH = 7.187 + log [0.189] / [0.202]

Answer

Molarity = [tex]1.4mol/L[/tex]

Explanation:

Molarity provides the number of moles of solute per liter of solution (moles/Liter). It is a means by which concentration of solution is measured.

SEE THE ATTACHMENT BELOW FOR STEP BY STEP SOLUTION.

Answer:

1.42 M

Explanation:

In this case have a dilution problem, therefore we need to use the dilution equation:

[tex]C_1*V_1=C_2*V_2[/tex]

What values we have?

[tex]C_1=3.82M[/tex]

[tex]V_1=526mL(0.516L)[/tex]

[tex]C_2=?[/tex]

[tex]V_2=?[/tex]

Now, we can calculate [tex]V_2[/tex] if we add the volumes, so:

[tex]0.516~L+~0.875~L=1.391~L[/tex]

So,  [tex]V_2=1.391~L[/tex]

We can plug the values in the equation:

[tex]3.82~M*0.516~L=C_2*1.391~L[/tex]

[tex]C_2=\frac{3.82~M*0.516~L}{1.391~L}[/tex]

[tex]C_2=1.42~M[/tex]

I hope it helps!

Answer:

[tex]P_{H_2}=1.9kPa[/tex]

Explanation:

Hello,

Here, by using the Dalton's law, we can quantify the total pressure of a gaseous mixture by knowing the partial pressure of each gas, in case, hydrogen, helium and argon:

[tex]P_T=P_{H_2}+P_{He}+P_{Ar}[/tex]

In such a way, since we actually know the partial pressure of helium and argon, and the total pressure, we can compute the partial pressure of hydrogen as shown below:

[tex]P_{H_2}=P_T-P_{He}+P_{Ar}=99.3kPa-42.7kPa-54.7kPa\\\\P_{H_2}=1.9kPa[/tex]

Best regards.

Answer:

2.9 M

Explanation:

Step 1: Given data

Moles of barium chloride (solute): 4.4 moles

Volume of solution: 1.5 liters

Step 2: Calculate the molarity of barium chloride in the solution

The molarity is a way to quantitatively express the concentration of a solute in a solution. The molarity is equal to the moles of solute divided by the volume, in liters, of solution.

[tex]M=\frac{4.4mol}{1.5L} =2.9 M[/tex]

Answer:

Volume, V2 at STP = 818.61ml.

Explanation:

Given the following parameters;

Volume, V1 = 1140ml

Volume, V2 =?

Temperature, T1 = 37ºC to Kelvin = 273+37 = 310K

Temperature, T2 = 273K is the standard temperature.

Pressure, P1 = 82.6kPa

Pressure, P2 = 101.3kPa is the standard pressure.

To solve for volume at standard temperature and pressure (STP), we would use the combined gas law;

The combined gas law is a combination of the other three gas laws, namely Gay Lusac's law, Boyle's law and Charles's law.

Combined gas law states that the ratio of the product or multiplication of volume and pressure to the temperature of a gas is equal to a constant.

Mathematically, [tex]PV/T = K[/tex]

P1V1/T1 = P2V2/T2

Let's make V2 to the subject formula;

Cross multiplying gives,

P1V1T2 = P2V2T1

Hence, [tex]V2 = (P1V1T2)/P2T1[/tex]

Substituting the parameters;

V2 = (82.6*1140*273)/101.3*310

V2 = 25706772/31403

V2 = 818.61ml.

Answer:

1.02 × 10³ g

Explanation:

Step 1: Write the balanced equation

2 CaCO₃ + H₂SO₄ ⇒ CO₂ + H₂O + CaSO₄

Step 2: Calculate the moles corresponding to 500 g of sulfuric acid

The molar mass of sulfuric acid is 98.08 g/mol.

[tex]500g \times \frac{1mol}{98.08g} = 5.10mol[/tex]

Step 3: Calculate the moles of calcium carbonate that react with 5.10 moles of sulfuric acid

The molar ratio of CaCO₃ to H₂SO₄ is 2:1. The moles that react of calcium carbonate are (2/1) × 5.10 mol = 10.2 mol

Step 4: Calculate the mass corresponding to 10.2 moles of calcium carbonate

The molar mass of calcium carbonate is 100.09 g/mol.

[tex]10.2mol \times \frac{100.09 g}{mol} =1.02 \times 10^{3} g[/tex]

Answer and Explanation:

A chemical formula is composed by chemical symbols (in letters, which indicate the chemical elements) and subscripts (numbers). For example, let see the chemical formula for carbon dioxide:

CO₂

The letters C and O are the chemical symbols for the elements carbon (C) and oxygen (O). The number 2 in subscript indicates that there are 2 atoms of O per molecule. The subscript 1 is generally not indicated in chemical formulae, so it is assumed that the number of atoms of C is 1.

Summarizing, the chemical formula CO₂ indicates us that the molecule if formed by 1 atom of the element carbon (C) and 2 atoms of the element oxygen (O).

Answer:

32 K is approx. -241.15° C

Answer:

Percent Yield = 94.237%

Explanation:

CO = Carbon Dioxide = Molar Mass 28g/mol

C = Carbon = 12g/mol

O = Oxygen = 16g/mol

Theoretical yield = 93.7 grams

Actual yield = 88.3 grams

Percent yield  = (actual yield /theoretical yield )x100

Percent Yield = (88.3/93.7)x100

Percent Yield = 94.237%

Answer:

d) The fraction of collision with total kinetic energy larger than activation energy  increases.

Explanation:

Hello,

In this case, kinetic models explain how the rate of a chemical reaction is affected by several factors. In such a way, specifically for temperature, when it increases, the average velocity of the particles is also increased, for that reason, the collision frequency increases since the molecules are more likely to collide as they move faster and encounter to each other.

Nonetheless, it is the minor reason because the main reason is that the effective collisions increase when the temperature is increased, and they are related with the fraction of collision with total kinetic energy that turns out larger than the activation energy, therefore, answer is d).

Best regards.

Answer:

Oxygen and Magnesium.

Based on the difference in electronegativity, potassium and sulfur, chlorine and lithium, and oxygen and magnesium can form ionic compounds, whereas lithium and calcium, sulfur and bromine, and manganese and chlorine cannot.

Ionic compounds are formed when there is a high electronegativity difference between two elements.

To determine whether the following pairs of elements can form ionic compounds, we need to look at their electronegativity difference:

1. Lithium and calcium: The electronegativity difference between Lithium and calcium is only 0.9, which is less than 1.7. Therefore, they cannot form an ionic compound.

2. Sulfur and bromine: The electronegativity difference between sulfur and bromine is 0.9, which is less than 1.7. Therefore, they cannot form an ionic compound.

3. Manganese and chlorine: The electronegativity difference between manganese and chlorine is 1.5, which is less than 1.7. Therefore, they cannot form an ionic compound.

4. Potassium and sulfur: The electronegativity difference between potassium and sulfur is 2.4, which is greater than 1.7. Therefore, they can form an ionic compound.

5. Chlorine and lithium: The electronegativity difference between chlorine and lithium is 2.8, which is greater than 1.7. Therefore, they can form an ionic compound.

6. Oxygen and magnesium: The electronegativity difference between oxygen and magnesium is 1.7, which is equal to 1.7. Therefore, they can form an ionic compound.

Therefore, based on the electronegativity difference between the elements, potassium and sulfur, chlorine and lithium, and oxygen and magnesium can form ionic compounds, while lithium and calcium, sulfur and bromine, and manganese and chlorine cannot form ionic compounds.

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Answer:

(b.) alkene

(i) aldehyde/ketone

(k.) ester

Explanation:

Peaks observed at:

Answer:

E = 1.47

Explanation:

To do this, you need to apply the Nerst equation which is the following:

E = E° - RT/nF lnQ (1)

Where:

E: cell voltage

E°: Standard potential reduction

R: universal constant

T: temperature of the system

n: number of electrons transfered during the reaction

F: Faraday constant.

Q: Equilibrium constant

However, as the reaction is taking place at 25 °C, and R and F have constant values, we can reduce the above expression to the following:

E = E° - 0.05916/n lnQ  (2)

We can get the value of Q because it has to do with the reaction which is the following:

2IO₃⁻(aq) + 12H⁺(aq) + 5Co(s) ----------> I₂(s) + 5Co²⁺(aq) + 6H₂O(l)

Now, using only the aqueous state the expression of Q will be:

Q = [Co²⁺]⁵ / [H⁺]¹² [IO₃⁻]²

Replacing the values we have:

Q = (7.82)⁵ / (1.54)¹² * (6.64)²

Q = 3.728

Knowing this, all we need to know now is the standard potential reduction of the reaction. To do so, we need to write the two semi equations of reduction and oxidation:

2IO₃⁻ + 12H⁺ + 10e⁻ ---------> I₂ + 6H₂O       E₁° = 1.20 V

5Co ---------> 5Co²⁺ + 10e⁻                          E₂° = 0.28 V

E° = 1.2 + 0.28 = 1.48 V

Now that we have all the values (n = 10) we can write now the nernst equation to calculate the cell voltage:

E = 1.48 - 0.05916/10 ln (3.728)

E = 1.48 - 0.005916 (1.315872)

E = 1.47 V

This will be the cell voltage

Answer:

30.0g/mol

Explanation:

Step 1: Given data

Step 2: Calculate the moles of the gas

We will use the ideal gas equation.

[tex]P \times V = n \times R \times T\\n = \frac{P \times V}{R \times T} = \frac{1atm \times 0.0933L}{\frac{0.0821atm.L}{mol.K} \times 273.15K} = 4.16 \times 10^{-3} mol[/tex]

Step 3: Calculate the molar mass of the gas

4.16 × 10⁻³ moles correspond to a mass of 0.125 g. The molar mass of the gas is:

[tex]\frac{0.125g}{4.16 \times 10^{-3} mol} =30.0g/mol[/tex]

The molar mass of the 0.125 g  of the gas occupies 93.3 mL at STP is 30.0 g/mol.

Number of moles of Gas at STP,

[tex]\bold{n =\dfrac {PV}{RT}}[/tex]

where,

P - pressure

V- volume

R- gas constant

T - temperature

Put the values in the formula,

[tex]\bold{n =\dfrac {1 \times 0.0933} {0.082 \times 273.15 }}\\\\\bold{n =4.16 \timesw 10^-^3}[/tex]

The molar mass of the gas can be calculated using formula,

[tex]\bold {m = \dfrac {w}{n}}\\\\\bold {m = \dfrac {0.125} {4.16 \times 10^-^3}}\\\\\bold {m = 30g/mol}[/tex]

The molar mass of the 0.125 g  of the gas occupies 93.3 mL at STP is 30.0 g/mol.

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Answer:

Yes, we should invest in renewable energies that decrease the levels of carbon dioxide in the atmosphere, that is, decrease the partial pressure of carbon dioxide in the environment since it is lethal for human life, in turn I consider that the exploitation of sources Oil was widely used but I think they should have an end, since they pollute oceans, oxygen, and fuels that are not necessary for today's technology since automobiles could be a base of electric or solar energy

Explanation:

Environmental pollution is a very serious current problem, since we should stop investing in oil sources and be able to keep those profits or that economy in another way or replace them with another resource, since if this greenhouse effect is not perceived as a current serious problem, we could run the risk of suffering natural catastrophes, systematic diseases, affections in the same life.

Answer: I think so.. (sorry if i am wrong)

Explanation:  Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. A physical property is a characteristic of matter that is not associated with a change in its chemical composition.

Answer:

I may not be correct but i think its pH = Kg

Explanation:

Answer:

B. in such a way that pH = pKa

Explanation:

Ideally, the pH of the desired solution should have the same pKa as the pH, making the ratio 1:1.

Answer:

ΔH = 130.5 kJ

Explanation:

Hello,

In this case, by using the Hess law, we compute the enthalpy of the required reaction:

C(s) + H2O(g) --> CO(g) + H2(g)

Thus, the first step is to keep the following reaction unchanged:

C (s) + O2 (g) → CO2 (g), ΔH = -393.5 kJ

Next, we invert and halve this reaction:

2 CO (g) + O2 (g) → 2 CO2 (g), ΔH= -566.0 kJ

So the enthalpy of reaction is inverted and halved:

CO2 (g) → CO (g) + 1/2 O2 (g) ΔH= 283 kJ

Then, we also invert and halve this reaction:

2 H2 (g) + O2 (g) → 2 H2O ΔH= -483.6 kJ

So the enthalpy of reaction is inverted and halved as well:

H2O → H2 (g) + 1/2 O2 (g) ΔH= 241.8 kJ

Finally, we add the three reactions to obtain the required reaction:

= C (s) + O2 (g) + CO2 (g) + H2O → H2 (g) + 1/2 O2 (g) + CO (g) + 1/2 O2 (g) + CO2 (g)

= C (s) + O2 (g) + CO2 (g) + H2O → H2 (g) + O2 (g) + CO (g) + CO2 (g)

= C (s) + H2O → H2 (g) CO (g)

So enthalpy is computed by:

ΔH = -393.5 kJ + 283 kJ + 241.8 kJ

ΔH = 130.5 kJ

Best regards.

Considering the Hess's Law, the enthalpy change for the reaction is 131.3 kJ.

Hess's Law indicates that the enthalpy change in a chemical reaction will be the same whether it occurs in a single stage or in several stages. That is, the sum of the ∆H of each stage of the reaction will give us a value equal to the ∆H of the reaction when it occurs in a single stage.

In this case you want to calculate the enthalpy change of:

C(s) + H₂O(g) → CO(g) + H₂(g)

You know the following reactions, with their corresponding enthalpies:

Equation 1: C (s) + O₂(g) → CO₂ (g)     ΔH = -393.5 kJ

Equation 2:  2 CO (g) + O₂ (g) → 2 CO₂ (g)     ΔH= -566.0 kJ

Equation 3: 2 H₂ (g) + O₂ (g) → 2 H₂O (g)     ΔH= -483.6 kJ  

First, to obtain the enthalpy of the desired chemical reaction you need one mole of C(s) on reactant side and it is present in first equation so let's write this as such.

Now, 1 mole of CO(g) must be a product and is present in the second equation. Since this equation has 2 moles of CO(g) on the reactant side, it is necessary to locate this component on the product side (invert it) and divide it by 2 to obtain 1 mole of CO(g).

When an equation is inverted, the sign of ΔH also changes.

And since enthalpy is an extensive property, that is, it depends on the amount of matter present, since the equation is divided by 2, the variation of enthalpy also is divided by 2.

Finally, 1 mole of H₂O(g) must be a reactant and is present in the third equation. Since this equation has 2 moles of CO(g) on the product side, it is necessary to locate this component on the product side (invert it) and divide it by 2 to obtain 1 mole of H₂O(g).

So, the sign of ΔH also changes and the variation of enthalpy is divided by 2.

In summary, you know that three equations with their corresponding enthalpies are:

Equation 1: C (s) + O₂(g) → CO₂ (g)     ΔH = -393.5 kJ

Equation 2: CO₂ (g) → CO (g) + [tex]\frac{1}{2}[/tex] O₂ (g)     ΔH= 283 kJ

Equation 3: H₂O (g) → H₂ (g) + [tex]\frac{1}{2}[/tex] O₂ (g)    ΔH= 241.8 kJ  

Adding or canceling the reactants and products as appropriate, and adding the enthalpies algebraically, you obtain:

C(s) + H₂O(g) → CO(g) + H₂(g)  ΔH= 131.3 kJ

Finally, the enthalpy change for the reaction is 131.3 kJ.

Learn more:

Answer:

pH = 9.03

Explanation:

The equilibrium of the NH₄Cl / NH₃ buffer in water is:

NH₃ + H₂O ⇄ NH₄⁺ + OH⁻

Initial moles of both NH₃ and NH₄⁺ are:

0.100L ₓ (0.20 mol / L) = 0.0200 moles

The NH₃ reacts with HCl producing NH₄⁺, thus:

NH₃ + HCl → NH₄⁺ + Cl⁻

That means, moles of HCl added to the solution are the same moles are consumed of NH₃ and produced of NH₄⁺

Moles added of HCl were:

0.025L ₓ (0.20mol / L) = 0.0050 moles of HCl. Thus, final moles of NH₃ and NH₄⁺ are:

NH₃: 0.0200 moles - 0.0050 moles = 0.0150 moles

NH₄⁺: 0.0200 moles + 0.0050 moles = 0.0250 moles.

Using H-H equation for bases:

pOH = pKb + log [NH₄⁺] / [NH₃]

Where pKb is -log Kb = 4.745.

Replacing:

pOH = 4.745 + log 0.0250mol / 0.0150mol

pOH = 4.967

As pH = 14- pOH

pH = 9.03