the human brain and spinal cord develop from which structures?

1.nerve cord

2.notochord

3.pharyngeal pouch

4.tail


Please help me!

Answer:

a

Explanation:

it's the most common thought of element when you need a compound from earth

The number of atoms of chlorine present in the compound is 1.96 x 10²³ atoms.

The number of chlorine atom present in CCl₄ is calculated as follows;

The molar mass of the given compound is calculated as follows;

CCl₄  = C (12g/mol) + Cl (35.5 g/mol) x 4

CCl₄  = 154 g/mol

The number of moles of the given compound is calculate as follows;

n = reactant mass / molar mass

n = ( 12.5 g ) / ( 154 g/mol)

n = 0.081 mole

The number of moles of chlorine present in the compound is calculated as follows;

Cl₄ = 4 x 0.081 mole = 0.325 mol

The number of atoms of chlorine present in the compound is calculated as follows;

1 mole = 6.022 x 10²³ atoms

0.325 mole = ?

= 0.325 x 6.022 x 10²³ atoms

= 1.96 x 10²³ atoms

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The value of the equilibrium constant, Kc, for this reaction is approximately 0.43 L/mol.

The balanced chemical equation for the reaction between ethanol and acid to form ester is:

CH₃CH₂OH + RCOOH ⇌ CH₃COOC₂H₅ + H₂O

where R represents the organic acid group.

From the given information, the initial concentration of ethanol and acid in the flask is 1.00 mol/L and 2.00 mol/L, respectively. At equilibrium, the concentration of ester is 0.86 mol/L.

The equilibrium constant expression for the reaction is:

Kc = [CH₃COOC₂H₅][H₂O]/[CH₃CH₂OH][RCOOH]

where the square brackets represent the molar concentrations of the respective species at equilibrium.

Substituting the given values, we get:

Kc = (0.86 mol/L) / (1.00 mol/L x 2.00 mol/L) = 0.43 L/mol

Therefore, the value of the equilibrium constant, Kc, is 0.43 L/mol.

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Answer:

The black solid is magnetic due to the special property of iron called ferromagnetism

6.9 g

Explanation:

The substance FeS is magnetic despite of the fact Fe^2+ is spin paired due to the special magnetic property of iron called ferromagnetism.

The equation of the reaction is;

Fe(s) + S(s) ----> FeS(s)

Number of moles of Fe = 5g/56g/mol = 0.089 moles

Since the reaction is 1:1, 0.089 moles of FeS is formed

For Sulphur;

Number of moles of sulphur = 2.5g/32 g/mol = 0.078 moles

Since the reaction is 1:1, 0.078 moles of FeS is formed

Hence sulphur is the limiting reactant.

So, mass of FeS produced = 0.078 × 87.91 g/mol = 6.9 g

Answer:

answer c aka it is cheaper than other elements

Answer:

because it's cheap and not hard to purify

why helium is inactive

The limiting reagent in this scenario is \(O_{2}\) because we have more \(H_{2}\) (20 moles) than is required (16 moles).

We must compare the mole ratios of the reactants to the stoichiometry of the balanced equation in order to identify the limiting reagent. The reaction's balanced equation is as follows:

2 H₂ + O₂ -> 2 H₂O

We can deduce from the equation that the \(O_{2}\) to \(H_{2}\) ratio is 1:2. Therefore, we require two moles of \(H_{2}\) for every one mole of \(O_{2}\).

We can determine the quantity of \(H_{2}\) required for the reaction if we have 8 moles of \(O_{2}\) and 20 moles of \(H_{2}\):

2 moles of \(H_{2}\) divided by 1 mole of \(O_{2}\) results in 16 moles of \(H_{2}\).

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Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 2500 × 5

We have the final answer as

Hope this helps you

Answer:

506.81J

Explanation:

H = MC(T1 - T0)

H = 5 × 0.897 × (419 - 306)

H = 5 × 0.897 × 113

H = 506.81 J

As per specific heat of aluminium ,506.81 J of energy is gained  by the sample.

Specific heat capacity is defined as the amount of energy required to raise the temperature  of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.

It varies with temperature  and is different for each state of  matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.

It is given by the formula ,

Q=mcΔT

For the given example, Q=energy

m=mass=5 g, C=0.897 J/g.K

T₂=419 K

T₁=306 K

substituting in the formula ,Q=5×0.897(419-306)=506.81 J.

Thus, 506.81 J of energy is required.

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The reaction is 2NOCl (g) ⇌2NO (g) + Cl₂ (g). The expression for the equilibrium constant will be 4.337 × 10⁻⁴ M

The forward reaction velocity constant and the backward reaction velocity constant are multiplied to produce the equilibrium constant. According to some sources, it is "the ratio of product to the molar concentration of product to product of the molar concentration of reactants." The difference between the equilibrium product and reactant concentrations is the equilibrium constant of a reaction. The concentration terms are elevated to suitable powers that are equivalent to stoichiometric coefficients.

Given, the reaction is 2NOCl (g) ⇌2NO (g) + Cl₂ (g).

K = \(\frac{[NOCl^2]}{[NO]^2 [Cl2]}\)

Δ \(n_{g}\) = (2+1) -2 = 1

Temperature T, 500 K

\(K_{p}\) value = 1.8 × 10⁻²  bar⁻¹

Now

\(K_{p} = K_{c} (RT)^{-ng}\)

= 1.8 × 10⁻² × (0.083 × 500)⁻¹M

= 4.337 × 10⁻⁴ M

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Answer:

4NaHCO3---->2Na2CO3+2CO2+2H2O

Answer:

Protons:

- positive

- aka cation

- in the nucleus along with the neutrons

Electrons:

- negative

- aka anion

- situated in the orbital shells/configuration levels (there are many names)

When two elements combine chemically, they form a compound. The compound has distinct chemical and physical properties that differ from the elements from which they are made.

A compound is a substance made up of two or more distinct components that are chemically linked together in a certain proportion. The chemical connection between elements is established by interactions between their outermost electrons, which results in the development of molecules or crystal formations. A compound's atoms are bonded together by chemical bonds, which can be ionic or covalent. Atoms transfer electrons to generate positively and negatively charged ions, which are subsequently attracted to each other in an ionic combination. Atoms share electrons in covalent compounds to produce stable electron configurations.

Depending on the nature of their chemical bonds and intermolecular forces, they can exist as solids, liquids, or gases. Some examples of compounds are water, carbon dioxide, sodium bicarbonate, salt(NaCl),  sugar (sucrose), etc.

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Answer:

1.) First thing to recognize is that it requires you to know the molecular formula for Iron(III) Oxide, which is Fe2O3. If you don't know this formula  in all textbooks there is a page that has it and other compounds listed. I would encourage you to review this page and memorize the other compounds as these compounds will come up in future questions.

2.) Now we will write an unbalanced equation, keeping in mind that molecular oxygen( O2) is used:

Fe + O2 ==> Fe2O3

3.) In balancing problems, I like to always start with Oxygen. Because there are 2 oxygen atoms on the reactant side and  three on the product side and we know that both of these numbers go into 6, we will use this to balance the oxygen. We will put a e in front of the molecular Oxygen and a 2 in front of the iron(III) oxide. This will balance the oxygens.

Fe + 3O2 ==> 2Fe2O3

However, notice now that the iron is still out of balance, This can be easily solved by having a 4 in front of the iron. Now everything is balanced!

4Fe + 3O2 ==> 2Fe2O3

Explanation:

A process through which a large molecule such as a protein could leave the cholera cell is generally referred to as: c) exocytosis.

Cholera can be defined as a type of disease which is typically caused by a bacteria that is referred to as Vibrio cholerae. Also, cholera gets into the body of a living organism through an ingestion of contaminated food or water.

Exocytosis simply refers to a process which typically involves a cell releasing a large amount of a material (bulk transport) outside of the cell, especially through the use of vesicles.

This ultimately implies that, exocytosis can be defined as a biological process in which living organisms release (expel) large amount of unwanted material by using the vesicles.

Additionally, exocytosis is a biological process that is initiated by the Golgi apparatus and it can be used to expel a large molecule such as protein from cholera cells.

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Complete Question:

In the first stage of cholera, the bacterium finds a host cell in the small intestine. The bacterium then releases toxic proteins called toxins near the host cell. Through which process could a large molecule such as a protein leave the cholera cell?

a) osmosis

b) diffusion

c) exocytosis

d) endocytosis

The balance net ionic equation for the spontaneous reaction that occurs as the cell operates is 2 Cr + 3 Cu2+ -----> 2 Cr3+ + 3 Cu and  Cr is the reducing agent and Cu2+ is the oxidizing agent.

A galvanic cell or a voltaic cell is an electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy. Galvanic cells are self-contained and portable so they can be used as batteries and fuel cells.

Any on-rechargeable battery that does not depend on an outside electrical source is a Galvanic cell. A galvanic cell (or a series of galvanic cells) is a battery that contains all the reactants needed to produce electricity.

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Correct option is c. 0

Let's discuss it further below.

In the Lewis structure for formaldehyde (H2CO), where C is the central atom, the formal charge on C is:

Step 1: Determine the number of valence electrons for C. Carbon has 4 valence electrons.
Step 2: Calculate the number of electrons assigned to C in the Lewis structure. In formaldehyde, C is bonded to 2 H atoms (each with 1 bond) and 1 O atom (with a double bond). This gives C a total of 4 bonds, so it has 4 assigned electrons.
Step 3: Calculate the formal charge on C using the formula: Formal Charge = (Valence Electrons) - (Assigned Electrons). Thus, Formal Charge on C = (4) - (4) = 0.

So, the formal charge on C in the Lewis structure for formaldehyde is 0 (option c).

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The empirical formula is the simplest formula for a compound which is defined as the ratio of subscripts of smallest possible whole number of the elements present in the formula. It is also known as the simplest formula.

write a balanced equation for the reaction between tantalum pentachloride and water?

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Substitution reactions can require a catalyst to be feasible. (a). A high temperature should be maintained in order to maximize the percent yield of the substitution reaction.; (b). A high pressure should be used in order to maximize the percent yield of the substitution reaction. ; The HCl gas should not be allowed to escape into another container

The reaction represented by the following equation is heated to maximize the percent yield.  

C2H6(8) + Cl2(g) + energy c HCl(l) + HCI()

a. To maximise the percent yield of the substitution reaction, a high temperature should be maintained. This is because increasing the temperature increases the kinetic energy of the molecules, allowing them to move faster and collide more frequently. This leads to an increased rate of reaction and a higher percent yield.

b. To maximise the percent yield of the substitution reaction, use a high pressure. This is because increasing the pressure increases the concentration of the reactants, which leads to more frequent collisions between the molecules and an increased rate of reaction.

c. Allowing the HCl gas to escape into another container is not permitted. This is because the HCl gas is a product of the reaction and removing it from the reaction vessel will decrease the yield of the reaction. Instead, the HCl gas should be kept in the same container as the reactants in order to maximize the percent yield of the substitution reaction.

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Answer:

C. Piece of wood in water

Explanation:

\(.\)

The inner electron shells of an atom are closer to the nucleus and contain electrons with lower energy levels compared to the outer electron shells. The key differences between the inner and outer electron shells include:

Energy Levels: The inner electron shells have lower energy levels than the outer electron shells. Electrons in the inner shells are more strongly attracted to the positively charged nucleus.

Occupancy: The inner electron shells are usually filled with electrons before the outer electron shells. The innermost shell can hold a maximum of 2 electrons, while the subsequent shells have higher capacity.

Shielding Effect: Electrons in the inner shells partially shield the outer electrons from the full positive charge of the nucleus. This shielding effect reduces the attraction between the outer electrons and the nucleus.

Chemical Reactivity: Outer electron shells are more involved in chemical reactions because they are farther from the nucleus and experience weaker attraction. Outer electrons are more easily gained, lost, or shared during chemical reactions, determining the atom's chemical behavior and reactivity.

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Answer:

Explanation:

Titration: titrate twice, the first time with an indicator to determine how much sodium hydroxide is needed to completely react with hydrochloric acid, and the second time without an indicator to prevent the contamination of the sodium chloride salt produced

Answer:

they have same atomic number as they are the same element & electrons

Answer: they both have the atomic (proton number) as they are the same element hence they also they have the same number of electrons. Therefore they have similar chemical properties, as the electrons determine the chemical property of an element.

Explanation: The numbers 35 and 37 are the mass numbers for the two isotopes of chlorine. They both have the same atomic number (proton number ) as they are the same

Answer:

the tree red

Explanation:

Copper (II) substances burn to produce bluish-green flames.

The copper (II) present in the wood will make the flame produce a bluish-green color.

This is because copper (II) compounds are known to produce flame colors that range from blue to bluish-green when tested in the laboratory.

This is because the electrons in the atoms of copper lose energy and drop to lower energy, releasing the lost energy as light in the process.

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i)   Either Q or R could potentially form an ionic bond with S because the element S has the highest electronegativity (6), while the other two elements have lower electronegativity values.

ii)

S and Q are more likely to form a polar covalent bond because the electronegativity difference between S and Q (6 - 3.64 = 2.36) is greater than the electronegativity difference between S and R (6 - 3 = 3).

iii)

The electronegativity difference between Q and R (3.64 - 3 = 0.64) is relatively small, indicating that they are more likely to form a non-polar covalent bond.

In a polar covalent bond, the electrons are shared unequally between the two atoms, thus creating a partial positive charge on one atom and a partial negative charge on the other.

The greater the difference in electronegativity between the two atoms, the more polar the bond will be.

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Answer:

The last one. Creativity.

Explanation:

Creativity makes things happen.

The time passed when only 0.125 M of compound A remains is 2.92 seconds.

The reaction is second-order in compound A, which means that the rate of the reaction is proportional to the square of the concentration of A. The rate equation can be expressed as:

Rate = k[A]²

Where k is the rate constant and [A] is the concentration of A.

To find the time passed when the concentration of A is 0.125 M, we can use the integrated rate law for a second-order reaction:

1/[A] - 1/[A₀] = kt

Where [A₀] is the initial concentration of A, and t is the time passed.

Rearranging the equation, we get:

t = (1/[A] - 1/[A₀]) / k

Substituting the given values, we have:

t = (1/0.125 M - 1/0.500 M) / 2.42 L/mol/s

Calculating the values inside the parentheses:

t = (8 - 2) / 2.42 L/mol/s

t = 6 / 2.42 s

t ≈ 2.48 s

Therefore, the time passed when only 0.125 M of compound A remains is approximately 2.48 seconds.

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Cl4Ge is the empirical formula of the give reaction.

Chemical formulas for compounds that simply specify the proportions of the elements they contain rather than the exact number or arrangement of atoms are known as empirical formulas. The element in the compound with the lowest whole number ratio would be this one.

The chemical formula for glucose is C6H12O6. For every mole of carbon and oxygen, there are two moles of hydrogen present. CH2O is the empirical formula for glucose. Ribose has the empirical formula CH2O as well as the chemical formula C5H10O5.

It can be determined from data on the mass of each component in a compound or from the composition's proportion.

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