In the reaction 4Al+__O2→2Al2O3, what coefficient should be placed in front of the O2 to balance the reaction?

Question 2 options:

1


2


3

Answer:

2

Explanation:

The sample has halved twice.

1/2 of 1/2 is 1/4, and 1/2 of 1 is 1/2.

Answer:

Sedimentation, filtration, and coagulation are the treatments that will help remove contaminants from minerals or from the pipes carrying water from a source.

Sedimentation is a process in which suspended particles settle out of water. It is one of the most basic techniques for removing particles from water. As particles settle, they become trapped in the bottom of a container or settle to the ground in an outdoor setting

Filtration is a method of removing particles from a fluid. It is a physical or chemical separation method that separates solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass.

Coagulation is the process of using chemicals to remove contaminants from water. By creating a chemical reaction, coagulation destabilizes particles and causes them to clump together. This helps to remove the contaminants from the water.

Disinfection is the process of eliminating or destroying pathogens that cause infection. Disinfection eliminates harmful microorganisms by destroying or inactivating them. The disinfectant is a chemical or physical agent that is used to destroy or inactivate harmful microorganisms.

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Answer:

C. water acts as a radiation shield to reduce the radiation level

Oxygen-16: 8 protons, 8 neutrons, 8 electrons

Oxygen-18: 8 protons, 10 neutrons, 8 electrons

Using atomic and mass numbers, we can find information about the makeup of atoms.

Protons

Every element has a unique number of protons, and every atom of the same element will have the same number of protons. This means that both oxygen atoms must have the same number of protons. The number of protons in an element is equal to its atomic number. Since oxygen has an atomic number of 8, all oxygen atoms will have 8 protons. This means that oxygen-16 and oxygen-18 have 8 protons.

Neutrons

The number of neutrons an atom of a certain element can have varies. Atoms of the same element that have different numbers of neutrons are known as isotopes. The number of neutrons can be found through the mass number. The mass number is the number that follows the dash in the name of the isotope. This number is equal to the protons plus the neutrons. So, to find the number of neutrons in an oxygen atom, subtract 8 protons from the mass number. This means oxygen-16 has 8 neutrons and oxygen-18 has 10 neutrons.

Electrons

Remember that electrons are negatively charged, protons are positively charged, and neutrons have no charge. The number of electrons in an atom determines the charge of the atom. If the number of electrons equals the number of protons, then the charge of the atom will equal 0. If there are more electrons, then the atom will be negatively charged and vice versa. Since neither of the atoms has any indication of a nonzero charge, the number of electrons must equal the number of protons. So, both oxygen atoms have 8 electrons.

Considering the definition of molar mass, the correct answer is option c): the mass of 1.85 moles H₂O₂ is 62.9 grams.

The molar mass of substance is a property defined as the amount of mass that a substance contains in one mole.

The molar mass of a compound is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.

In this case, you know the molar mass of the elements is:

So, the molar mass of the compound H₂O₂ is calculated as:

H₂O₂= 2× 1 g/mole + 2× 16 g/mole

Solving:

H₂O₂= 34 g/mole

You can apply the following rule of three: If by definition of molar mass 1 mole of the compound contains 34 grams, 1.85 moles of the compound contains how much mass?

mass= (1.85 moles× 34 grams)÷ 1 mole

mass= 62.9 grams

Finally, the mass of 1.85 moles H₂O₂ is 62.9 grams.

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Which of these conjugated dying's will not react are dienes that are in cisoid forn, which can react in dieals alder. In general, electron-withdrawing groups on the dienophile speed up Diels-Alder processes.

The locked trans dienes do not react in the Diels-Alder reaction, whereas the cyclic cis dienes are so reactive that they may react with one another, making these conformations two extremes. Because one molecule serves as the diene and the other as the dienophile, for instance, cyclopentadiene dimerizes. Bridged bicyclic compounds are produced by cyclic dienes. Diels-Alder reactions can only occur in conjugated dienes with the s-cis structure. A diene cannot conduct a Diels-Alder reaction if it is not conjugated or cannot be in the s-cis configuration. Ring-based dienes are incapable of rotating, hence

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Answer:

Oxygen

Explanation:

First, list out all the ions in the aqueous solution:

Ag+, NO3-

H+, OH-

In the anode, the substance lose electrons to undergo oxidation.

From the 4 ions, only OH- can lose electrons to form water and oxygen,

4OH- --->  O2 + 2H2O + 4e-

While others tend to gain electrons to form new substances instead (they undergo reduction).

Oxygen is the gas produced.

The gas should be treated as the Oxygen.

here First, list out all the ions that should be in the aqueous solution:

Ag+, NO3-

H+, OH-

In the anode, the substance loses electrons for undergoing oxidation.

From the 4 ions, only OH- can lose electrons to form water and oxygen.

The balanced chemical equation be like

4OH- --->  O2 + 2H2O + 4e-

While on the other hand, it tend to gain electrons to create new substances. Therefore, Oxygen is the gas produced.

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Although there is some variation amongst tissues, the physiologically typical intracellular pH ranges from 7.0 to 7.4. Skeletal muscle in mammals typically has a pHi of 6.8 to 7.1.

A cell is the basic membrane-bound living thing and can either have one or more cells. All the molecules required for an organism to function are found in cells. An atomic is 10-10m in size. In contrast, a cellular is 10-6 metres in size. Because all cells are composed of atoms, they are therefore bigger than atoms.

Acid excretion, efflux through plasma membranes, and buffering mechanisms all work together to precisely preserve the pH of body fluids. Protons are extruded from the cytosol into the extracellular space through the organic cation transporter (MCT) and the Na+/H+ exchanger (NHE).

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Answer:

C. Natural abundance

Explanation:

The percentage of natural occurrence of an isotope of an element on the planet is the natural abundance or the geonormal abundance.

The standard enthalpy change for the reaction 2A+B⇌2C+2D is  664 kJ/mol and The heat that is absorbed when 3.70 mol of A reacts is 2456.8  J

The heat changes that take place as reactants combine to generate a product are measured by the enthalpy of a reaction.

The following formula can be used to determine the enthalpy change of a reaction:

Hess's law states that

Enthalpy of reaction =  product's enthalpy - the reactant's enthalpy.

Considering the given reaction: 2A + B ⇌ 2C + 2D  

Enthalpy of reaction =  product's enthalpy - the reactant's enthalpy.

Enthalpy of reaction (ΔH°f) = (2 C + 2 D) - (2 * A + B)

Enthalpy of reaction  (ΔH°f)  = {[2(223) + 2(-523)] - [2(-245) + 2(-387)]}

Enthalpy of reaction  (ΔH°f)  = 664 kJ/mol

ΔH = q ÷ n

ΔH = molar enthalpy (heat) of solution

q = amount of energy (heat) released or absorbed

n = moles of solute

so. q = ΔH xn

q = ΔH xn

q = 664 kJ/mol x 3.70 mol

Q= 2456.8  J

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Answer:

The molarity of the solution is 1.23M.

Explanation:

1st) To calculate the molarity, it is necessary to have the moles of the solute per liter (or 1000mL) of solution. So, we have to convert 1.20g of HCl to moles, using the molar mass of HCl (36.5g/mol):

2nd) Now we know that 0.032 moles of HCl are contained in 25.0mL of water.

HCl is the solute and water is the solvent, so with the density of HCl (1.3g/mL) we have to calculate the mL of HCl:

Now, adding the solute plus the solvent, we get the volume of the solution:

3rd) Finally, we can calculate the molarity of the solution with a mathematical rule of three:

So, the molarity of the solution is 1.23M.

When we talk about radioactive decays, we will have 4 main types of decays:

1. Alpha decay: in this case, we have an atom losing 2 protons and 2 neutrons, therefore its atomic number will decrease by 2 and atomic mass will decrease by 4

2. Beta decay: in this case, we have a neutron turning into a proton and releasing an electron, therefore we will have an increase in the atomic number of the atom

3. Positron emission: similar case to number 2, but now, we have a proton turning into a neutron and we have the release of a positron, therefore in this case, we will have the atomic number down by 1

4. Gamma decay: In this case, we have changes in neither atomic number nor atomic mass, because we don't have the release of particles, but instead we have the release of gamma rays, which are a very radioactive type of rays

For the equation number 1, we have:

18/8 O -> 14/6 C + 4/2 He

For equation number 2, we have a neutron capture, this is a process to produce Plutonium 239, which starts with Uranium 238 capturing a neutron, becoming Uranium 239, after this, 239 U will go through Beta decay, where a neutron turns into a proton, and release an electron, therefore we will have Neptunium 239, 93 protons and 146 neutrons, Neptunium 239 will undergo another beta decay, and become Plutonium 239, 94 protons and 145 neutrons

238/92 U + 1/0 n -> 239/92 U

For equation number 3, we have:

18/8 O + 1/1 H -> 19/9 H

Answer:

The answer is (e) none of the above. The combined gas law relates the pressure, volume, and temperature of a gas, so all three variables (pressure, volume, and temperature) must be considered and at least one of them should be held constant to use the combined gas law. The mass of the gas sample, number of moles of gas, and number of gas molecules are not directly related to the combined gas law.

(E, E)-3,5-octadiene, molecular formula is C8H14, molecular weight is 110.20,(3E,5E)-octa-3,5-diene is its IUPAC name.

What is IUPAC?

The International Union of Pure and Applied Chemistry (IUPAC) is a global federation of National Adhering Organizations dedicated to the progress of the chemical sciences, particularly through the creation of nomenclature and terminology. It is an International Science Council member (ISC).

What is the Molecular formula?

A molecule is made up of two or more atoms that have joined together chemically. A molecular formula is the chemical representation of a molecular compound that lists the types and quantities of atoms that make up each molecule.

Hence, the structure of the compound (E, E)-3,5-octadiene is in the image attached. The image is from Pubchem, National library of medicine (NCBI).

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The choice of solution has a concentration of 1.144 mol/kg molality.

Molarity corresponds to the moles of solvent divided by the amount of solution in litres, whereas molality is equal with the moles of solvent divided by the quantity of solvent in kilogrammes.

Since 1 mole of solute is present in 1 litre for the solution, which contains both the solute and the solvent, 1 molar aqueous solutions are more concentrated than one decays aqueous solutions.

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The equilibrium constant for the reaction PCl₃(g)+Cl₂(g) ⇌ PCl₅(g) at

400K is 1/Kc.

The ratio of the amount of reactant to the amount of product that is used to predict the chemical behavior of a reaction is known as the equilibrium constant for chemical reactions. The rate constants remain unchanged at a specific temperature.

When the reactants and products do not change in any significant way over time, this is known as chemical equilibrium. When the forward and reverse reactions happen at the same rate, this is the condition. The equilibrium constant, K, serves as a description of this state of equilibrium.

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Answer:

\(MM_{C_5S_2}=132.19g/mol\)

Explanation:

Hello!

In this case, since the computation of the molar mass requires the molecular formula, we first realize that of pentacarbon disulfide is C₅S₂ due to the given prefixes. In such a way, we multiply the atomic mass of carbon by five and that of sulfur by two as shown below:

\(MM_{C_5S_2}=5m_C+2m_S\)

Thus, we plug in the atomic masses given in the periodic table to obtain:

\(MM_{C_5S_2}=5*12.01+2*32.07\\\\MM_{C_5S_2}=132.19g/mol\)

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The equilibrium constant, k of the reaction in which case, the concentrations of the given reactants and products are as indicated is; Choice A; K = 3.1 x 10⁵

It follows from above that the concentrations of the reactants and products are as follows; [H2] = 0.10 M, [N2] = 0.10 M, and [NH3] = 5.6 M at equilibrium.

Hence, the equilibrium constant of the reaction in discuss is;

K = [5.6]²/[0.10]³[0.10]

k = 5.6² × 10⁴

k = 3.136 × 10⁵

K = 3.1 × 10⁵.

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Answer:

See the explanations

Explanation:

In the Baeyer-Villiger reaction, we will produce an ester from a ketone (see the first reaction). In our case, the ketone is Acetophenone therefore phenyl acetate would be produced.

Now, for the mass calculation, we have to keep in mind that we have a reaction with a 1:1 ratio. So, if we have 0.02 moles of acetophenone and 0.036 moles of m-CPBA the limiting reagent would be the smallest value in this case acetophenone.

Additionally, if we have a 1:1 ratio and the limiting reagent is 0.02 moles of acetophenone we will have as product 0.02 of phenyl acetate, if we take into account the molar mass of phenyl acetate (136.05 g/mol), we can do the final calculation:

\(0.02~mol~acetophenone\frac{1~mol~phenyl acetate}{1~mol~acetophenone}\frac{136.05~g~phenyl acetate}{1~mol~phenyl acetate}=2.72~g~phenyl acetate\)

I hope it helps!

Answer:

An alkaline is a substance that dissolves in water to produce hydroxyl ions (OH-)

Explanation:

The pH range of an alkaline is from 8–14.

Acidic pH ranges from 0–6.9.

If the caffeine concentration in a particular brand of soda is 2.99 mg/oz, drinking, The number of cans of soda would be lethal is 258 cans.

Caffeine is a stimulant. In the brain, it blocks the effects of a chemical called adenosine, which makes you feel sleepy. we then feel more alert and energetic, which is why many people drink soda, coffee or tea to stay awake. Caffeine may keep you awake even if you don't want it to

Given

v = 10 000/3.23 =3095.96 oz

Therefore,

Number of cans = 3095.96 /12 =258 cans

If the caffeine concentration in a particular brand of soda is 2.99 mg/oz, drinking, The number of cans of soda would be lethal is 258 cans.

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Answer:

There can be numerous derived quantities all branching from the basic 7 base quantities.

Explanation:

The  derived SI units are

m/s² that is of acceleration that is rate of change of velocity

m/s is the SI unit of velocity that is rate of change of displacement

Nm is the SI unit of Torque i.e T= rxF

and so on

Because any natural element used in the cathode produced negative particles that bent to a positive charge, scientists concluded that ll atoms contained negative electrons.

A polarized electrical device's cathode is the electrode from which a regular current exits. The abbreviation CCD, which stands for Cathode Current Departs, might be used to remember this definition. Positive charges move in the direction described by a conventional current.

A cathode is a drawback. As an electron donor, it functions. It serves as an acceptor of electrons. The anode of an electrolytic cell is where the oxidation reaction occurs.

The negatively charged ions are drawn to the cathode, which is the negative electrode. Lead ions travel through the metal use negatively charged terminal of the battery and onto the lead ions because metal ions are usually positive. There must be a way to remember cathodes and anodes, cations and anions.

Thus, option A is correct.

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Helen takes 35 nights to knit a total of 175 centimeters of scarf. Hence, she will take 36 nights to knit 180 centimeters of scarf.

Length is a basic measurement in for an object which is basically taken in meters or centimeters. The basic unit of length in American standard is meters (m) and in CGS system it is centimeters.

It is given that, Helen knit a total of 175 centimeters of a scarf over 35 nights. Then, the length she knit in one nigh is calculated as:

175/35 = 5 cm.

Therefore, the number of nights required to complete 180 cm is :

180 /5 = 36

Thus, she will take 36 nights to knit a total of 180 cm of scarf.

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Answer:

Br-CH2-CH(CH3)2-C(Cl)H-CH(CH3)2-CHO

Explanation:

The molecule has a total of 14 carbon atoms, 13 hydrogen atoms, and 1 bromine atom. The carbon atoms are arranged in a chain with a methyl group attached to the second carbon atom, a chlorine atom attached to the third carbon atom, and two methyl groups attached to the fourth carbon atom. The fifth carbon atom has a carbonyl group attached to it.

The molecule is an aldehyde, which means that it has a carbonyl group (C=O) at the end of the chain. The carbonyl group is polar, and the oxygen atom has a partial negative charge. The hydrogen atom has a partial positive charge. This polarity makes the aldehyde group susceptible to nucleophilic attack.

The bromine and chlorine atoms are both electrophilic, which means that they have a partial positive charge. This makes them susceptible to nucleophilic attack.

The methyl groups are non-polar and do not have any significant reactivity.

The molecule is a chiral molecule, which means that it has a mirror image that is not superimposable on itself. This is because the carbon atom with the carbonyl group is attached to four different groups.

The molecule is a liquid at room temperature and has a strong odor. It is used in a variety of products, including perfumes, flavorings, and plastics.

Answer:

I think it's A. I'm pretty sure.

Explanation:

Answer:

Coal, oil and natural gas are called _________A. fossil fuels

First, we have to remember the equation to calculate the heat of evaporation:

Q is the heat, ΔH is the vaporization heat of the substance, and m is the mass.

If we have the vaporation heat in terms of moles (as in this case), we have to multiply it by the number of moles instead of the mass. For that purpose, we have to calculate the molecular weight of the water:

Then, we can pass the grams to moles:

And we can finally calculate the heat:

The answer is that the necessary heat to evaporate the water is 63.9894 kJ approx.