If 25 mL of KOH were needed to neutralize 15 mL of 3.5 M HBr, calculate the molarity of the base

Here’s a hint for you…the Latin root for color is "chroma"

The Latin root for body is "soma"...

That should help you figure out the answer for yourself!

P.S. The answer is Chromosomes.

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Answer:

percentage yield = 88.25%

Explanation:

Firstly, write the chemical reaction and balance the equation.

Potassium react with oxygen to produce potassium oxide.

K + 02 → K2O

Balance the equation

4K + 02 → 2K2O

The limiting reactant is K so the yield of potassium oxide can be calculated using grams for potassium.

atomic mass of K = 39.1g/mol

grams for 4 mole of potassium =  4(39.1) = 156.4 g

grams for 2 moles of K2O = 2( 39.1 × 2 + 16) = 188.4 g

If 156.4 g of K produces 188.4 g of K2O

6.92 g of K will produce ? gram of K2O

cross multiply

grams of K2O = 6.92 × 188.4/156.4

grams of K2O = 1303.72/156.4

grams of K2O = 8.33585677749

grams of K2O = 8.34 g

percentage yield = actual yield/theoretical yield × 100

actual yield = 7.36 g

theoretical yield = 8.34 g

percentage yield = 7.36/8.34 × 100

percentage yield =         736/8.34

percentage yield = 88.2494004796%

percentage yield = 88.25%

Taking into account definition of percent yield, the percent yield for the reaction is 88.25%.

In first place, the balanced reaction is:

4 K + O₂ →2 K₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use a simple rule of three as follows: if by stoichiometry 32 grams of O₂ reacts with 156 grams of K, 4.28 grams of O₂ reacts with how much mass of K?

[tex]mass of K=\frac{4.28 grams of O_{2} x 156 grams of K}{32grams of O_{2}}[/tex]

mass of K= 20.865 grams

But 20.865 grams of K are not available, 6.92 grams are available. Since you have less mass than you need to react with 4.28 grams of O₂, K will be the limiting reagent.

Considering the limiting reagent, the following rule of three can be applied: if by reaction stoichiometry 156 grams of K form 188 grams of K₂O, 6.92 grams of K form how much mass of K₂O?

[tex]mass of K_{2} O=\frac{6.92 grams of Kx188 grams of K_{2} O}{156 grams of K}[/tex]

mass of K₂O= 8.34 grams

Then, 8.34 grams of K₂O can be produced from 6.92 grams of K and 4.28 grams of O₂.

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

[tex]percent yield=\frac{actual yield}{theoretical yield}x100[/tex]

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

In this case, you know:

Replacing in the definition of percent yields:

[tex]percent yield=\frac{7.36 grams}{8.34 grams}x100[/tex]

Solving:

percent yield= 88.25%

Finally, the percent yield for the reaction is 88.25%.

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Iodine-131 has a shorter half-life than cobalt-60.

We are given;

We are supposed to explain the difference between the two instances;

We need to define half life;

Answer:

The radius of the sun is 7x10^5 kilometers, and that of the Earth is about 6.4x10^3 kilometers. Use scientific notation to show that the Sun's radius is about 100 times the Earth's radius. The Sun's radius is 10^10 the Earth's radius.

In scientific notation, the radius of the sun is 109 times the radius of the Earth.

The sun is almost a perfectly shaped sphere. The equatorial diameter and the polar diameter of the sun differ only by only 6.2 miles or 10 km. The sun's mean radius is 432,450 miles or 696,000 kilometers.

According to this, the diameter would be about 864,938 miles or 1.392 million km. Around 109 Earths could be lined across the face of the sun. The circumference of the sun is about 2,715,396 miles or 4,370,006 km.

Sun is the biggest thing in our neighborhood or in our solar system. But, compared to other stars that have been observed, the sun is called an average star. Betelgeuse, which is a red giant, is about 700 times bigger than the sun and 14,000 times brighter. The classification of the sun is as a G-type main-sequence star or a G dwarf star,  

Therefore, in scientific notation, the radius of the sun is 109 times the radius of the Earth.

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Answer:

The configuration of the atom would be 2-8-2.

Explanation:

Any atom of an element combines with other element to complete its octet and become stable.

The electron configuration of the given atom is 2-8-6. That means the atom has 6 electrons in its outermost shell. To become stable the atom should have 8 electrons in its outermost shell. The given atom has 6 electrons so it either lose 6 electrons or gain 2 electrons to complete its octet.

But we know the atom having 5,6,7 electrons in its outermost shell they do not lose, they gain either 3 or 2 or 1 electrons to complete its octet.

So we say that atom with the electron configuration 2-8-6 bond with the atom having electron configuration 2-8-2.

A neutral atom with the electron configuration 2-8-6 would most likely form a bond with an atom having the configuration 2-5, such as a neutral nitrogen atom.

A neutral atom with the electron configuration 2-8-6 refers to an atom with 16 electrons. To determine the atom it would most likely form a bond with, we consider the octet rule which states that atoms are more stable when they have 8 electrons in their valence shell. Based on this rule, the atom with a configuration that would most likely form a bond with the given atom is an atom with 5 electrons in its valence shell, such as a neutral nitrogen atom with the electron configuration 2-5.

Answer:

The  volume (in ml) of a 3.57 M solution of [tex]ZnBr_2[/tex] that contains 0.884 moles of  [tex]ZnBr_2[/tex] is 247.61g mL

Explanation:

According to the definition of Molarity

which sates

"The amount of moles of a substance present in one litre of the solution is called as Molarity."

3.57M [tex]ZnBr_2[/tex] solution implies that 1000 mL of the solution conatins 3.57Moles of [tex]ZnBr_2[/tex]

Hence , 3.57 moles of [tex]ZnBr_2[/tex] is present in the 1000 ml of solution

Now,

In 1 mole of [tex]ZnBr_2[/tex] is  present in the =[tex]\frac{1000}{3.57}[/tex]ml of solution

Similarily ,

In 0.884  moles of[tex]ZnBr_2[/tex] is  present in the [tex]\frac{1000\times 0.884}{3.57}[/tex] of solution= 247.61g mL

Answer:

Eye colour is one example of a trait caused by the concentration of melanin in genes.

Explanation:

Eye colour is decided based on two distinct factors- pigmentation of the eye’s iris and scattering of the light by the 'stroma of the iris'. It is a 'polygenic phenotypic' character in a human being.  

The pigmentation of the iris varies between brown and  black, that all depends on melanin concentration in the iris stroma, iris pigment epithelium and the cellular density of trauma. Further, the eye colour genetics are complicated and multiple genes are responsible for same.

Final answer:

Eye color is an inherited trait determined by multiple genes and alleles, where certain alleles are dominant over others. A green-eyed child with brown-eyed parents suggests both parents are heterozygous for the green eye color allele. The pattern of inheritance is also influenced by epistasis and linkage.

Explanation:

Eye color is an example of a trait that is determined by multiple genes. In humans, eye color can be influenced by multiple alleles, where certain alleles are dominant over others. For example, the allele for brown eyes is dominant over the allele for blue eyes, meaning that a person with one copy of each allele will have a brown iris.

Moreover, the inheritance pattern of eye color is more complex due to the presence of epistasis, where the expression of one gene is influenced by one or more other genes. In the instance provided, a child with green eyes born to parents with brown eyes indicates that both parents carry the allele for green eyes, making them heterozygous. Therefore, choice b. Both parents are heterozygous, having the green trait on the green-blue eye gene, explains how this is genetically possible.

Answer:

Molarity =5.32 M

Explanation:

Given data:

Mass of glucose = 239 g

Volume = 250 mL (250 /1000 = 0.25 L)

Molarity = ?

Solution;

Formula:

Molarity = number of moles / volume in litter

Number of moles:

Number of moles = mass/ molar mass

Number of moles = 239 g / 180.2 g/mol

Number of moles = 1.33 mol

Molarity:

Molarity = number of moles / volume in litter

Molarity = 1.33 mol / 0.25 L

Molarity =5.32 M

In H2SO4, H is +1, S is +6, and O is -2; in CaSO4, Ca is +2, S is +6, O is -2; in HF, H is +1 and F is -1. These oxidation numbers follow standard rules based on the elements' positions in the periodic table and their common states in compounds.

To determine the oxidation numbers in the compounds H2SO4, CaSO4, and HF, we use the standard rules for assigning oxidation numbers.

These values follow from the rules that the oxidation number of hydrogen is usually +1, that of oxygen is usually -2, and the sum of oxidation numbers in a neutral compound must equal 0. Fluorine always has an oxidation number of -1 in its compounds.

Answer: 0.088 moles

Explanation:

Parameters given:

Mass of AgNO3 = 15.0g

To know the number of moles, given such parameter, we need to find and use the molecuar weight formular. The molecuar weight is mass per mole

Molecular weight = mass / mole

Molecular weight of AgNO3

Ag + N + 03

107.8682 + 14.0067 + 15.9994(3)

(Note, that the weight of each compounds are standards)

= 169.8731g/mole

Using our molecular weight formular

Moles of AgNO3 in 15.0g

Let Number of Moles be represented as Y

169.8731g/mole = 15.0g / Y

Therefore,

Y = 169.8731 / 15.0g

Y = 0.088 moles

No of Moles of AgNo3 in 15.0g = 0.088moles

Answer:

T₂ = 669.2 K

Explanation:

Given data:

Initial pressure = 660 torr

Initial temperature = 26 °C (26 +273 = 299 K)

Final volume = 280 mL ( 280/1000 = 0.28 L)

Final pressure = 940.0 torr

Final volume = 0.44 L

Final temperature = ?

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₁V₁/T₁ = P₂V₂/T₂  

T₂ = P₂V₂ T₁ /P₁V₁

T₂ = 940 torr × 0.44 L  × 299 K / 660 torr × 0.28 L

T₂ = 123666. 4 torr. L. K / 184.8 torr. L

T₂ = 669.2 K

Answer:

V₂ =  1200 mL

Explanation:

Given data:

Volume of gas = 250 mL

Pressure of gas = 3.6 atm

Final pressure = 0.75 atm

Final volume = ?

Solution:

P₁V₁ = P₂V₂

V₂ = P₁V₁ /P₂

V₂ = 3.6 atm . 250 mL /0.75 atm

V₂ = 900 atm. mL /0.75 atm

V₂ =  1200 mL

Answer:

Blue: 440 nm; 6.81 × 1014 Hz; 4.51 × 10−19 J.

Explanation:

I know

The frequency of blue light with a wavelength of 440nm is calculated using the speed of light and the wavelength, resulting in a frequency of approximately 6.818  imes 10¹⁴ Hz.

The frequency of blue light with a wavelength of 440nm can be calculated using the speed of light and the formula for frequency, which is frequency (f) = speed of light (c) / wavelength ( ambda). Given that the speed of light (c) is 3.00  imes 10^8 ms⁻¹, and the wavelength ( ambda) of blue light is 440nm (which is 440  imes 10⁻⁹m when converted to meters), we can calculate the frequency as follows:

f = c /  ambda

f = (3.00  imes 10^8 ms⁻¹,  / (440  imes 10⁻⁹ m)

After performing the calculation:

f  = 6.818  imes10¹⁴Hz

Therefore, the frequency of blue light with a wavelength of 440nm is approximately 6.818  imes 10¹⁴ Hz.

Answer:

The soil is more developed and more fertile.

Explanation:

The lack of immediate decomposers in temperate forests allows the vertical profile of the soil to develop more thanks to the accumulation of plant matter. As a result, the soils of temperate forests are eroded less easily by the element and they also tend to be more fertile than rain forest soils due to the slow decomposition of organic matter.

Taxonomy is the procedure for ranking plants.

Explanation:

The plants are ranked depending upon the resemblances and differences it has from another kind of plants. They can be ranked depending upon their leaves, roots, stems and other structures. They are defined into more general categories depending on the similar traits in the same group.

The plants are broadly classified into vascular and non vascular .Example, a flowering plant is a higher green plant and based on its gross structure does lie in the kingdom of Plantae, not in fungus or bacteria.

To react completely with 3.70g of dry slaked lime, 1.12 liters of chlorine gas would be required at STP, based on mole calculations and the ideal gas law.

To calculate the volume of chlorine gas that would react completely with 3.70g of dry slaked lime (Ca(OH)₂), we need to follow a series of steps:

First, we calculate the moles of Ca(OH)₂ using its molar mass (Ca = 40, O = 16, H = 1). The molar mass of Ca(OH)₂ is: (40) + (2 x 16) + (2 x 1) = 74 g/mol.

Next, we find the moles of Ca(OH)₂ in 3.70g by dividing the mass by the molar mass: moles of Ca(OH)₂ = 3.70 g / 74 g/mol = 0.05 moles.

According to the equation, 1 mole of Ca(OH)₂ reacts with 1 mole of Cl₂. Therefore, we need 0.05 moles of Cl₂.

We use the ideal gas law at standard temperature and pressure, where 1 mole of a gas occupies 22.4dm³. The volume of Cl₂ needed is 0.05 moles x 22.4 dm³/mole = 1.12 dm³, or 1.12 liters.

Therefore, 1.12 liters of chlorine gas would be required to react completely with 3.70g of dry slaked lime at standard temperature and pressure (STP).

The statement that indicates the energy that must be absorbed to initiate in the reaction pathway is "A".

A reaction mechanism, also known as a reaction route, specifies the molecular processes that occur in a chemical reaction. It defines the series of reactions that must occur in order to create a desired result.

When the bonds in the reactant molecules are disrupted, more energy is absorbed than is released when new bonds are generated in the products.

The amount of free energy which must be necessarily added to get from the energy level of the reactant molecules to the energy level of the product is the activation energy for the forward reaction. In plenty of other respects, activation energy is the input amount of energy needed for a reaction to take place.

Many chemical processes, including essentially all biochemical processes, do not occur spontaneously and require an initial energy input (known as the activation energy) to begin. When studying both endergonic and exergonic reactions, activation energy must be taken into account.

Hence the correct answer is A.

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Answer:

Elements :)

Explanation:

Neon (Ne), being an element, is the substance that cannot be decomposed by chemical means from the given list. All other options are chemical compounds that can be decomposed into elements.

The question is about identifying a substance that cannot be decomposed by chemical means from a given list. Substances that cannot be chemically decomposed are known as elements, which are the most basic form of matter that cannot be broken down into simpler substances. Based on the options provided (Ne, N₂O, HF, H₂O), Neon (Ne) is an element and thus cannot be decomposed chemically into simpler substances.

The rest of the substances are chemical compounds: N₂O (nitrous oxide), HF (hydrogen fluoride), and H2O (water). These compounds can be decomposed into their elements by chemical reactions, such as hydrolysis or electrolysis for water. Therefore, the correct answer is Ne, which is an inert noble gas and an element that cannot be decomposed by chemical means. Option A

Answer:

carbon dioxide

Explanation:

Green spaces are important in cities because they reduce the carbon dioxide concentrations that are produced most by vehicular activity. At the same time, these green spaces provide the city with an invaluable source of oxygen that otherwise would not be found in city limits due to pavimentation and lack of naturally forested areas or green spaces.

Answer:

C. carbon dioxide and water

Explanation:

Water is a small molecule that easily diffuses through a cell membrane (osmosis) despite the lipid tails. Oxygen is a small molecule and it’s nonpolar, so it easily passes through a cell membrane. Carbon dioxide, the byproduct of cell respiration, is small enough to readily diffuse out of a cell.

Answer:

N₂ + 3H₂  → 2NH₃

Explanation:

Nitrogen react with hydrogen and form ammonia. The one mole of nitrogen gas react with two moles of hydrogen and form two moles of ammonia.

The oxidation state of nitrogen is -3 while that of hydrogen is +1. That's why two balance the charge one with one nitrogen atom three hydrogen atom react and with two nitrogen atom with a charge of -6 six hydrogen atoms are attached (+6).

Chemical equation:

N₂ + H₂  → 2NH₃

Balanced chemical equation;

N₂ + 3H₂  → 2NH₃

The balanced equation for the synthesis reaction between nitrogen and hydrogen to produce ammonia is N2 + 3H2 → 2NH3.

The balanced equation that shows the product formed when nitrogen with an oxidation state of -3 undergoes a synthesis reaction with H2, which has an oxidation state of +1, is:

N2 + 3H2 → 2NH3

In this reaction, one molecule of N2 reacts with three molecules of H2 to produce two molecules of NH3. The coefficients in the balanced equation represent the mole ratio required for the reaction to occur.

Answer:

A. Si-28

B.Fe-56

Explanation:

Answer:

a. ²⁸₁₄Si, Silicon-28

b. ⁵⁶₂₆Fe, Iron-56

Explanation:

a. For the nuclear symbol, the mass number of the isotope is on top while the atomic number is at the bottom. For example, ²⁸₁₄Si. The hypen notation for the isotope is Silicon-28 based on the atomic number and mass number.

b. The mass number of the isotope is equal to the sum of protons and neutrons = 26+30 = 56. The atomic number is the number of protons = 26. Thus, the nuclear symbol is ⁵⁶₂₆Fe and the hypen notation is Iron-56.

“Water” is the best thermal insulator.

Option: B

Explanation:

“Thermal insulators” are the materials which do not allow heat to transfer. “Water” is the substance which does not transfer heat. Hence, the “water” is the best “thermal insulator”. Water is the bad conductor of thermal heat. Water has “low thermal conductivity” than other substances, so this acts as an insulator as long as it is not traveled from one place to another. Heat is transferred when a “hot object collides” with “the cold objects”. The “thermal conductivity” of “water” is 0.6 W/m K.

Answer:

Explanation:

Oxidation:

1) Oxidation involve the removal of electrons.

2) Oxidation occur when oxidation state of atom of an element is increased.

Reduction:

1) Reduction involve the gain of electron.

2) Reduction is occur when number of electrons increased in an atom and oxidation state decreased.

Consider the following reactions.

4KI + 2CuCl₂  →   2CuI  + I₂  + 4KCl

the oxidation state of copper is changed from +2 to +1 so copper get reduced.

CO + H₂O   →  CO₂ + H₂

the oxidation state of carbon is +2 on reactant  side and on product side it becomes  +4 so carbon get oxidized.

Na₂CO₃ + H₃PO₄  →  Na₂HPO₄ + CO₂ + H₂O

The oxidation state of carbon on reactant side is +4. while on product side is  also +4 so it neither oxidized nor reduced.

H₂S + 2NaOH → Na₂S + 2H₂O

The oxidation sate of sulfur is -2 on reactant side and in product side it is also -2 so it neither oxidized nor reduced.

The  most comprehensive definition is 2nd definition which involves the increase or decrease in oxidation state.

An oxidation-reduction (redox) reaction is a chemical reaction in which one or more elements undergo a change in oxidation number. One reactant is reduced and another reactant is oxidized.

An oxidation-reduction (redox) reaction is a chemical reaction in which one or more elements undergo a change in oxidation number. In these reactions, one reactant is reduced and another reactant is oxidized. For example, in the reaction 2Mg(s) + O2(g) → 2MgO(s), magnesium (Mg) is oxidized from an oxidation state of 0 to +2 and oxygen (O2) is reduced from an oxidation state of 0 to -2.

The most comprehensive definition of a redox reaction is the one that states that redox reactions are those in which one or more elements involved undergo a change in oxidation number. This definition encompasses all redox reactions, including those that involve changes in oxidation number for two or more elements.

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TRUE

Explanation:

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability. By sharing their outer most electrons, atoms can fill up their outer electron shell and gain stability. So, it is true.

Answer:

Increasing order of Electronegativity:

Neon < Aluminum < Sulfur <Oxygen

0 < 1.61 < 2.58 < 3.44

Explanation:

Electronegativity:

Electronegativity is the power of an atom to attract shared pair of electron in a bond.

Trend in Periodic Table:

Electronegativity of the following Compounds is

1. Electronegativity of sulfur:

Sulfur is in group 4 and its

EN of Sulfur = 2.58

2. Electronegative of oxygen:

Oxygen is in group VIA and much electronegative than Sulfur.

The EN oxygen = 3.44  

3. Electronegative of Neon:

Neon is group VIIIA member and most stable element thats why have it have no data for electronegativity.

The EN of Neon = 0

4. Electronegative of Al:

It is group IIIA member and have less electronegativity

The EN of Aluminum= 1.61

So the Increasing order of electronegativity is

Neon < Aluminum < Sulfur <Oxygen

The order of increasing electronegativity for aluminum, sulfur, oxygen, and neon is: aluminum < sulfur < oxygen < neon. This order is determined by the increasing concentration of positive charge in the nucleus and the arrangement of electron configurations.

The elements in question, sulfur, oxygen, neon, and aluminum, can be ranked in order of increasing electronegativity by looking at their positions on the periodic table. Electronegativity increases from left to right across a period, and from bottom to top in a group. Thus, the order of increasing electronegativity would be as follows: aluminum < sulfur < oxygen < neon. This is due to the electron configurations of these elements as well as the increasing concentration of positive charge in the nucleus as one moves from left to right in a period and downward across a group.

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Answer:A

Explanation:

Formula of equilibrium constant is product divide by reactant

Answer:

A

Explanation:

Earthquakes are said to occur at faults where tectonic plates run into each other because they have been observed to occur at those tectonic plate boundaries.

Part of the evidence for the theory of plate tectonics is the predictable occurrence of earthquakes and volcanoes along plate boundaries. The Pacific Ring of Fire is an example of a seismically active zone that has been observed and labelled based on the noted activity.

An atom is smaller than an element since an element is composed of many atoms. Atoms make up the smallest unit of an element that maintains the element's properties. The size of atoms varies and can be compared using the periodic table, with atoms generally increasing in size down a group and decreasing across a period.

When comparing the size of an atom to that of an element, it is essential to understand that these terms describe different concepts in chemistry. An atom is the smallest unit of matter that retains the properties of an element, meaning it is a single particle. Conversely, an element is a pure substance made up of one type of atom. Therefore, while atoms are the tiny building blocks that make up elements, the term 'element' refers to the collective group of these atoms when considered as a whole. For example, a gold nugget is composed of multiple gold atoms but is still referred to as the element gold. Given this distinction, atoms are the smaller of the two when comparing size.

Size-wise, individual atoms can vary depending on the type of element. For instance, a helium atom is smaller than a lead atom. If we refer to the periodic table, we can compare the relative sizes of atoms based on their position. Typically, atoms increase in size as you move down a group (column) and decrease as you move across a period (row) from left to right. Hence, elements found further down and to the left of the periodic table generally have larger atoms than those towards the top right. However, it's often necessary to consider atomic radii and various other factors to make precise comparisons between atom sizes.

Answer: 13 proton, 10 electron and 14 neutron.

Explanation: electron are 10 because 3 electrons are transfer to other atom.

Answer:

Proton = 13

Electron = 10

Neutron = 14

Explanation:

Al3+ means Al that  has lost 3 electrons. Al has 13 protrons and 13 electrons. Having lost 3 electrons, Al3+ is left with 10 electrons.

Neutron + protron = relative atomic number

n + 13 = 27

n = 27 - 13 = 14