HELP !!!!!!! pls. with chemistry

Gold and copper were the first forms of matter investigated by humans because they were pretty and have a shiny appearance.

Gold and copper have a shiny face and they were used in the production of ornaments and jewelry. Along with jewelry many other precious items were made from gold and copper. Gold and copper were so valuable forms of matter and they are also economically used by many countries. Gold was mostly used in making of ornaments and copper was used in making of frames.

In today's modern world mainly gold is one of the most precious element which is obtained for economical use.

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Assuming the concentration of the NaOH solution that reacted with the sulfuric acid is 1.0 M, the mass of the sulfuric acid that reacted is 3.01 g.

A neutralization reaction is a reaction in which an acid reacts with a base to form salt and water only.

In the given reaction, a given amount of sulfuric acid was neutralized by 61.37 m:L of a NaOH solution.

The equation of the neutralization reaction is given below:

2 NaOH (aq) + H₂SO₄ (aq) ----> Na₂SO₄ (aq) + 2 H₂O (l)

The mole ratio of the reaction shows that 2 moles of NaOH solution will react with 1 mole of H₂SO₄ solution.

The moles of NaOH reacting = concentration * volume in liters

The concentration of the NaOH solution is not given. Assuming the concentration of the NaOH solution is 1.0 M

Moles of NaOH reacted = 1.0 * 61.37 mL * 1 L / 1000 mL

Moles of NaOH reacted = 0.06137 moles

Moles of  H₂SO₄ reacted = 0.0614 / 2

Moles of  H₂SO₄ reacted = 0.0307 moles

Mass of  H₂SO₄ reacted = 0.0307 * 98.09

Mass of  H₂SO₄ reacted = 3.01 g

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The balanced equation by hit and trial method is:

Zn + 2HCl → ZnCl2 + H2

Because a metal is replaced by another metal, the interaction between hydrochloric acid and zinc produces a single-displacement reaction.

This can be shown by,

B + CD → BD + C

There are two requirements: either B and D must be different metals (or any element that may form a cation, such as a hydrogen), while C must be an anion, or B and D must be halogens, while C must be a cation.

Count the Zn, Cl, and H atoms on each side of the chemical equation to balance the HCl-Zn reaction equation. To balance the equation, just alter the coefficients or the numbers that come before the atoms or compounds. The equation appears as follows after the coefficients have been changed:

ZnCl2 + H2 → Zn + 2HCl

Balance the molecular equation first.

Zn + 2HCl → ZnCl2 + H2

The net ionic equation will be, once the number of ions on both sides of the reaction is equalized by crossing them out.

Zn + 2H+ + 2 Cl– → Zn2+ + 2Cl– + H2

The balanced equation will be,

Zn + 2HCl → ZnCl2 + H2

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A solution is prepared by dissolving sodium benzoate and benzoic acid in water to give a 9 m mol / liter concentration of each compound. The mixture has a pH of 4.21 at 25 °C. the acid dissociation constant of benzoic acid, Ka is 6.1 × 10⁻⁵.

the pH of solution is given as :

pH = pka + log ( [sodium benzoate / benzoic acid])

4.21 = pka + log 1

pka = 4.21

pka = - log ka

ka = 10^- pka

ka = 6.2 × 10⁻⁵

Thus, A solution is prepared by dissolving sodium benzoate and benzoic acid in water to give a 9 m mol / liter concentration of each compound. The mixture has a pH of 4.21 at 25 °C. the acid dissociation constant of benzoic acid, Ka is 6.1 × 10⁻⁵.

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One mole of CS₂ and two moles of H₂S are formed as products and 3 moles of CH₄ are leftover.

A limiting reagent is a reactant that is fully exhausted from the reaction mixture at the completion of a  reaction. The limiting reactant will decide the maximum amount of product.

Given, a balanced chemical equation of the reaction between methane and sulphur is:

[tex]CH_4 + 4S\longrightarrow CS_2 +2H_2S[/tex]

Given, the number of moles of the sulphur = 4

The number of moles of methane = 4

From the chemical reaction, one mole of methane reacts with four moles of sulphur. Therefore, four moles of sulphur fully react with one mole of methane and three moles of methane leftover.

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Polyatomic ions: [tex]CH_3COO^-[/tex], [tex]NO_3^-[/tex], [tex]NH^+[/tex], [tex]CN^-[/tex], [tex]Li^+[/tex], and [tex]OH^-[/tex]

Monatomic ions: [tex]Ca^{2+[/tex], [tex]O^{2-[/tex], and [tex]Fe^{3+[/tex]

In chemistry, monoatomic ions are ions that consist of only a single type of atom. They are usually positive or negatively charged and are otherwise known as simple ions. Examples include  [tex]Ca^{2+[/tex], [tex]O^{2-[/tex], and [tex]Fe^{3+[/tex]

Polyatomic ions, on the other hand, are ions that consist of more than one atom, unlike monoatomic ions. The two or more atoms are covalently bonded and the entire structure behaves like a single chemical entity in reactions. Polyatomic ions are otherwise known as molecular ions.

Examples of polyatomic ions are  [tex]CH_3COO^-[/tex], [tex]NO_3^-[/tex], [tex]NH^+[/tex], [tex]CN^-[/tex], [tex]Li^+[/tex], and [tex]OH^-[/tex]

Thus, from the diagram:

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1) The transition that produces the least energy is n = 4 → n = 3

2) The transition that produces a photon with the highest frequency is n = 6 → n = 3

3) The  transition that produces a photon with the shortest wavelength n = 4 → n = 3

We know from the Bohr model that an electron that is found in the hydrogen atom can be moved from a lower to a higher energy level and that would happen when the electron is able to absorb energy in the form of visible light.

Looking at the transitions as we have it here, we can see that the photon that would photons produce the least energy would be two levels that are closest together.

Also, the photon that would have the highest frequency is the photon that is involved in the transition that has the furthest energy apart from each other.

The transition that produces  a photon with the shortest wavelength must also be farthest  apart in energy.

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Answer:

Number of protons in the nucleus of an atom

To determine if the piece of plastic has a density greater or less than 1 g/cm³, the piece of plastic is placed in water, if it sinks, it has a greater density, but if it floats, it has a lesser density.

The density of a substance measure how compact the substance is.

For fluids such as water, objects that are denser than water will sink in water. However, if the density is less than that of water, it will float in water.

The density of water is 1 g/cm³.

Hence, objects that have densities greater than 1 g/cm³ will sink in water, whereas objects that have densities less than 1 g/cm³ will float in water.

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Answer: C. A tornado is much smaller

Explanation: A tornado can be a mile long while hurricanes can be 50 miles long.

Metallic bonds occur amid metal atoms. Whereas ionic bonds combine metals with non-metals, metallic bonding fixes several metal atoms.

An ionic bond is formed by joining a metal and a nonmetal, while a covalent bond is formed by allying two nonmetals. So we check the periodic table to see if our compound is made up of metals or nonmetals, or of two nonmetals.

Covalent compounds are built when two nonmetals react with each other. Since hydrogen is a nonmetal, binary compounds that carry hydrogen are also usually covalent compounds. Metallic elements produced compounds with non-metallic elements with the help of ionic bonds.

So we can conclude that In metals, the electrons leave the outer shells of metal atoms, devise positive metal ions and a 'sea' of delocalized electrons.

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Answer:d

Explanation:

An object is placed in 20 mL of water. This water rose to a level of 26 mL. The object has a mass of 18 g. the density of the object is 3 g/mL.

given the data as follows :

mass of object  =  18 g

volume of object = final volume - initial volume

volume of object = 26 mL - 20 mL

                             = 6 mL

the density expression is given as:

Density = mass / volume

Density = 18 g / 6 mL

Density = 3 g/mL

Thus, An object is placed in 20 mL of water. This water rose to a level of 26 mL. The object has a mass of 18 g. the density of the object is 3 g/mL

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Option D. The atoms rearrange in the chemical reaction so that glucose is made.

A chemical reaction is a manner in which one or extra substances, the reactants, are transformed into at least one or extra different materials, the goods. materials are both chemical factors or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create one-of-a-kind substances as merchandise.

Examples of chemical reactions in everyday life consist of photosynthesis, rust, baking, digestion, combustion, chemical batteries, fermentation, and washing with soap and water. Chemical reactions arise everywhere in the global around you, now not simply in a chemistry lab.

On the idea of the product fashioned, special forms of reactions are Combustion response, Decomposition response, Neutralization response, Redox response, Precipitation or Double-Displacement reaction, Synthesis response

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Answer:

26.03 inHg

Explanation:

1 atm = 29.92 inHg

0.87 atm = 29.92 inHg x 0.87

0.87 atm = 26.03 inHg

Answer:

Strength:

Weakness:

The difference between the molecules that have dipole forces and those that have London forces is that the molecules that have dipole forces are polar while those that have London forces are not.

We know that dipole forces are one of the kinds of intermolecular forces that exist. Let us note that a molecule is composed of the primary bond forces that hold the atoms of the molecule together and then the secondary bond forces that do hold the molecules together.

Now, the kind of interactions that exists between the molecules is the reason for the properties of the compound that we see. The molecules have not been shown here but I would discuss the properties of the London forces and the dipole forces.

Note that the molecules that do have the dipole forces have an electronegativity difference between the atoms of the molecule. The molecules that have the London forces are largely non polar.

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In an investigation of the decomposition of water, a student compared the amount of oxygen in one test tube to the amount of hydrogen in the other test tube is There is one - half as much as hydrogen.

In decomposition of water , water can be broken into the hydrogen gas and the oxygen gas. The water decomposition reaction is given as :

2H₂O   ------>     2H₂     +     O₂

The ratio of  hydrogen and oxygen in the decomposition reaction of water is 2 : 1.

Thus, In an investigation of the decomposition of water, a student compared the amount of oxygen in one test tube to the amount of hydrogen in the other test tube is There is one - half as much as hydrogen.

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-18,037.5  are joules are needed to increase the temperature of 150 g of water from 313K to 338 K.

What is joules?

In the International System of Units (SI), a joule is a unit of work or energy equal to the work done by a force of one newton acting through one metre. It is named after the English physicist James Prescott Joule and equals 107 ergs, or about 0.7377 foot-pounds. The joule is equal to one watt-second in electrical terms, which is the amount of energy released in one second by a current of one ampere through a resistance of one ohm.

The distinction between heat and temperature can be difficult to grasp. Heat is essentially the total amount of kinetic energy that a substance's molecules contain, and it is measured in joules (J). Temperature is measured in degrees and is proportional to the average kinetic energy of the individual molecules. When the same quantity of heat is applied to different materials, the temperature rises at varying rates depending on the substance's specific heat capacity. If you know the amount of the substance and its specific heat capacity, you may determine the final temperature.

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A Biotechnologist decides to use directed evolution as an enzyme engineering technique when the enzyme mechanisms is understood and provides insight to engineering Why is directed evolution important?

A potent method for enhancing the functionality of proteins is directed evolution. When the biological function is unclear or there is little chemical understanding of the substrate and protein structure, directed evolution generates hundreds of variants in order to find the optimal solution.

What is enzyme engineering technique?

In order to increase the usefulness and activity of existing enzymes, enzyme engineering approaches use recombinant DNA technology to develop new proteins and enzymes with designer functions.

What is rational design?

In synthetic science and biomolecular designing, sane plan (RD) is an umbrella term which welcomes the system of making new particles with a specific usefulness, in light of the capacity to foresee how the atom's construction (explicitly got from themes) will influence its conduct through actual models.

Hence, Biotechnologist most likely to decide to use directed evolution as an enzyme engineering technique as opposed to rational design when the enzyme mechanism is understood and provides insight to engineering .

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Answers answer questions and

The order of boiling point from the highest to the lowest from the given compounds above are as follows:

CH3CH2CH2CH2CH2OH - CH3CH2CH2CH2CH2Br - CH3CH2CH2CH2CH3 - CH3CH2CH3.

The correct order is option b, d, c and a.

The boiling point of substances can simply be defined as that temperature at which liquids boils and then change to vapor or steam.

However, from the above given task, the organic compound, CH3CH2CH2CH2CH2OH has the same boiling simply because of its power to participate in hydrogen bond formation. This compound CH3CH2CH2CH2CH2OH is known as 1-pentanol.

So therefore, we can confirm that the compound from above the correct order of boiling point from the highest to the lowest is 1-pentanol, 1-bromopentane, pentane and propane respectively.

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The element is in 2nd group, 3rd period and s block.

How to check the group, period and block of the elements by looking at the electronic configuration?

The total number of valence electron gives us the group, the total number of shells gives us the period and the shell which the valence electron is entering tells us about the block it belongs to.

In [Ne]3s2, the valence electron is 2, the number of shells is 3 that is 1,2 and 3. the valence electron is entering the the s subshell.

Therefore, in [Ne]3s2, the group is 2nd, the period is 3 and it belongs to s block.

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Explanation:

Write a short report describing your ideas for a school of the future. You can suggest changes to:

• school buildings and classrooms.

• the library

• the cafeteria

• how classes are taught.

Give a reason for each of your suggestions. Use a variety of synonyms and accurate vocabulary.

200 words only

The mass of iron (II) oxide that must be used to produce 10.6 g of iron would be 14.37 grams.

Iron is produced from iron (II) oxide by reacting with carbon monoxide according to the following equation:

[tex]Fe_2O_3 + 3CO -- > 2Fe + 3CO_2[/tex]

The equation already obeys the law of conservation of atoms. Hence. it is a balanced equation.

The mole ratio of iron (III) oxide that reacts and the iron that is produced according to the equation is 1:2.

Now, in a particular reaction involving iron (III) oxide and carbon monoxide, 10.6 grams of iron were produced. The amount of iron (III) oxide used can be obtained using the mole ratio from the balanced equation of the reaction.

Recall that: mole = mass/molar mass

Molar weight of iron = 56 g/mol

Mole of 10.6 g of iron = 10.6/56

                                    = 0.19 moles

Since the mole ratio is 1:2, the equivalent mole of iron (III) oxide that reacts can be obtained:

                  0.19/2 = 0.09 moles

Molar mass of iron (III) oxide = 159.69 g/mol

Mass of 0.09 mol iron (III) oxide = 0.09 x 159.69

                                                    = 14.37 grams

Thus, the amount of iron (III) oxide that must be used to produce 10.6 g of iron would be 14.37 grams.

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This reaction, CIO + O - CI + O2, is an example of an endothermic chemical reaction, where the reactants take heat energy from their environment and use it to create products.

Endothermic chemical reactions occur when the reactants take in heat energy from their environment to create products. A cooling effect is produced by these reactions because they cause their surroundings to become cooler.

Exothermic means that the chemical reaction releases energy. In exothermic reactions, bonds are broken in the reactants, but more energy is released when the bonds are broken in the products. Endothermic chemical processes are those that take up (or utilize) energy.

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Answer:

b.Independent variable

Explanation:

The independent variable is the one that is changed by the scientist. To insure a fair test, a good experiment has only one independent variable. As the scientist changes the independent variable, he or she records the data that they collect.

.

Answer:

Br- has 35 protons and 36 electrons

Explanation:

Do you mean Br-?

Br has atomic number of 35 => 35 protons.

Neutral Br has 35 electrons.

Br- has 1 extra electron, resulting in total of 36 electrons.

If a gas has a volume of 145 mL at 125 °C, then it will have 108.56 mL at 25 °C.

According to Charles’ law, the volume of a gas is directly proportional to the temperature.

Thus, V1/T1=V2/T2 .......(i)

Here, V1 ⇒ initial volume

T1  ⇒ initial temperature in Kelvin

V2 ⇒ final volume

T2 ⇒ final temperature in Kelvin.

In the given question:

V1 = 145mL

T1 = 125°C= (125+273)K= 398K

T2 = 25°C= (25+273)K= 298K

Putting these values in equation (i),

145mL / 398K = V2 / 298K

Solving for V2, we get

V2 = 145mL * 298K /398 K

V2 = 108.56 mL

Therefore, at 25 °C, the gas will have a volume of 108.56 mL.

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