Which one of the following weak acids is the strongest?
A) HCN (Ka = 6.3 × 10-10)
B) HClO (Ka = 3.0 × 10-8)
C) HNO2 (Ka = 4.5 × 10-4)
D) HF (Ka = 6.5 × 10-4)

Answer:

the oxidation number of those elements is 2 because some of them are molecules

Answer:

Antione Lavoisier-Divided elements into four categories

John Newlands-arranged elements according to their atomic mass

Johann Wolfgang Dobereiner-created groups of three elements, each based on similar properties

Dmitri Mendeleev-used patterns to predict undiscovered elements

Explanation:

Classification of elements in the old periodic table was based on their atomic mass proposed by newlands. Different patterns for predicting undiscovered elements were contributed by Mendeleev.

Periodic table is a classification of all the elements discovered into different groups. Groups are vertical columns  having elements of similar properties and same number of valence electrons.

The modern periodic table is based on the atomic number of elements in the increasing order. This trend is originated from many concepts proposed  by various concepts.

It was Dmitri Mendeleev who proposed some patterns based on the atomic mass of elements to determine the position of each elements in periodic table.

John Newlands was first to classify the elements based on their atomic weight. Johann Wolfgang Dobereiner introduced the law of triads. He classified the elements to groups of three members where, the mass of middle element is exactly the aromatic mean of the mass of top and bottom element.

Antoine Lavoisier classified elements into four categories namely metals, nonmetals, gases and earths.

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Your question is incomplete. But your complete question probably was:

Match each scientist with the contribution he made to the arrangement of elements in the periodic table

Dmitri Mendeleev

Johann Wolfgang Dobereiner

John Newlands

Antoine Lavoisier,    

divided elements into four categories

used patterns to predict undiscovered

elements

created groups of three elements,

each based on similar properties

arranged elements according to their

atomic mass

Answer:

Calcium is the metal so its 29.439%

Explanation:

Calcium Ca 29.439%

Oxygen O 47.008%

Sulfur S 23.553%

False. The pineal gland produces melatonin, not oxytocin and serotonin.

False. The pineal gland primarily produces melatonin, a hormone that regulates sleep-wake cycles. Oxytocin is produced by the hypothalamus and stored in the pituitary gland, while serotonin is primarily produced by specialized cells in the gastrointestinal tract and also in the brain.It is not entirely accurate to say that the pineal gland produces oxytocin and serotonin.The pineal gland is primarily responsible for producing and secreting the hormone melatonin, which helps regulate the body's sleep-wake cycle. While the pineal gland does contain some serotonin-producing cells, it is not a major source of serotonin in the body. Similarly, while oxytocin has been detected in the pineal gland, it is primarily produced by the hypothalamus and released from the posterior pituitary gland.Therefore, the statement that the pineal gland produces oxytocin and serotonin is false.

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Answer:  C. The particles in salt water are spread throughout.

Explanation:

Homogeneous mixtures: It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different. There is no physical boundary between the dispersed phase and dispersion medium.  Example: Salt dissolved in water.

Heterogeneous mixtures: It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different.  There is a physical boundary between the dispersed phase and dispersion medium. Example: sand in water.

Answer:

Its c

Explanation:

A solution is a mixture where one substance is dissolved in another. One example of a solution is salt water. Why does salt water appear to be a single substance even though it contains more than one substance. Got it right in school city

The anticodons corresponding to the codons on the mRNA (from part A) is 5' CGA - AAA - GUU 3'.

Anticodons are nucleotide sequences on tRNA molecules that are complementary to the codons found on mRNA molecules.

The anticodons on tRNA molecules determine the amino acid that is carried by the tRNA.

Just like codons, anticodons occur in triplets of nucleotide sequences.

Considering the codons on the mRNA molecule:

3’ GCT | TTT | CAA | AAA ’5

The complementary anticodon will be:

5' CGA - AAA - GUU 3'

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The subshell representation of an element of Group IV is option C. s² p², since it contains 4 valence electrons.

In the Periodic Table, the Groups are the columns. For the Main-group elements, the group number coincides with the number of electrons in the valence shell.

Which of the following could be the subshell representation of an element of Group IV?

A. s². No, since there are 2 valence electrons.

B. s² p³. No, since there are 5 valence electrons.

C. s² p². Yes, since there are 4 valence electrons.

D. s² p¹. No, since there are 3 valence electrons.

The subshell representation of an element of Group IV is option C. s² p², since it contains 4 valence electrons.

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Answer: Iodine,

, is located in period 5, group 17 of the periodic table, and has an atomic number equal to

53

.

plss brainleist

Explanation:

Answer:

In addition, the number of valence electrons present in the elements of these groups denotes the group. The valence electrons present in their elements reflect their particular group, which is why they are termed representative elements.

Explanation:

Answer:

14.7°C

Explanation:

Q = m·ΔT·c

ΔT = \(\frac{Q}{m*c}\)

ΔT =\(\frac{1320 J}{230 g* 0.39 J/gC}\)

     = 1320 J / ((230 g) * (.39 J/g°C)

ΔT = 14.7 °C      

The source of pollution to look for when trying to ensure clean air in your home includes formaldehyde, radon, and tobacco smoke; nitroglycerine is not a typical source of indoor air pollution.

Formaldehyde is commonly found in many household products, such as adhesives, paints, and furniture made of composite wood. It can irritate the eyes, nose, and throat, and prolonged exposure has been linked to cancer. Radon is a radioactive gas that can seep into homes from the ground and can cause lung cancer. Tobacco smoke is a major indoor air pollutant that contains over 7,000 chemicals, including 70 known carcinogens. It can cause respiratory and cardiovascular problems, and even non-smokers can be affected by secondhand smoke. Nitroglycerine, on the other hand, is a highly explosive substance and is not commonly found in homes as a source of air pollution.

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The number of moles of helium that contains 3.29 × 1021 atoms is 5.49 × 10-3 moles.

What is helium?

Helium is a colorless, odorless, and tasteless chemical element, and is the second-lightest element in the periodic table. It is a noble gas, meaning it has a very low level of reactivity, and it is found in abundance in the universe. In the atmosphere, helium is the second most abundant element, making up about 24% of the total elemental mass.

The number of moles of helium that contains 3.29 × 1021 atoms can be calculated using Avogadro's number. Avogadro's number is the number of atoms in one mole of a substance, which is equal to 6.02 × 1023 atoms.

Therefore, the calculation is as follows:

Number of moles of helium = 3.29 × 1021 atoms ÷ 6.02 × 1023 atoms/mole = 5.49 × 10-3 moles.

Hence, the number of moles of helium that contains 3.29 × 1021 atoms is 5.49 × 10-3 moles.

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Answer:i dont know

Explanation:

I D

K

Answer:

Isomers are defined as the molecules or polyatomic ions which have similar molecular formula but different in arrangements of atoms.

Isomers can be found  in food items carrying glucose (C6H12O6), galactose or fructose,  they all have the same chemical formula but differ structurally and chemically.

Glucose is found in vegetables and milk, galactose found in dairy products, and Fructose is found in fruit juices.

Answer:

The Moon does not have any light of its own and it shines because its surface reflects sunlight. During a total lunar eclipse, the Earth moves between the Sun and the Moon and cuts off the Moon's light supply. When this happens, the surface of the Moon takes on a reddish glow instead of going completely dark.

Explanation:

Answer:

Since the Moon only reflects light from the Sun, when the Earth blocks the way between the Moon and the Sun, no light can reach the Moon and it is darkened. This is, again, known as the lunar eclipse.

Explanation:

Hope this helped!

Answer:

Composition can be referred to as it's build.

Explanation:

An example is when wood is burned, its structure is no longer compact. It is now ash.

Answer: Light

Explanation:

The environment abiotic factors like sunlight, water, air, and soil are important for the growth of the plants. A wildflowers is a plant that grows in wild. It was not intentionally seeded or planted.

The light is one of the important environmental factor. As the wildflowers are blooming earlier than the large trees. Thus the wildflowers are receiving the light earlier than large trees.

Answer:

Composite volcanoes. ... They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs and may rise as much as 8,000 feet above their bases.Muh. 28, 1432 AH

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 = 8 × 15

We have the final answer as

Hope this helps you

The term for the propane and butane phases that can be liquefied is "liquefied petroleum gas" or LPG. LPG is a mixture of propane and butane gases that are compressed and cooled to a point where they transition from their gaseous state to a liquid state.

This process of converting the gases into a liquid form allows for easier storage, transportation, and handling. LPG is commonly used as a fuel for heating, cooking, and powering various appliances. It is widely available in portable cylinders and larger storage tanks. LPG has a higher energy content compared to its gaseous form, making it a convenient and efficient fuel source. The ability of propane and butane to be liquefied and stored as LPG is due to their relatively low boiling points and the pressure at which they are compressed. By controlling the temperature and pressure, the gases can be condensed into a liquid state, allowing for greater convenience and versatility in their use.

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Molar mass of N2 = 14×2=28g/mol

Moles of N2 =mass/molar mass

Mass of N2 = moles × molar mass

Mass of N2 = 15.7 × 28 = 439.6 kg

The half reaction for cell anode that include the phases of all species in chemical equation is 2Ag⁺ (aq) + Sn(s) ------> 2Ag(s) + Sn²⁺ (aq)

The Reduction half reaction (or cathode reaction):-

Ag⁺(aq)  +  e⁻  ---------> Ag(s)..........(1)

The Oxidation half reaction (or anode reaction) :-

Sn(s) --------> Sn²⁺(aq) + 2e⁻  ............(2)

Therefore, Overall reaction :-

2(1) + (2)

or, 2Ag⁺ (aq) + Sn(s)  --------> 2Ag(s) + Sn²⁺ (aq)

A Voltaic Cell (otherwise called a Galvanic Cell) is an electrochemical cell that utilizes unconstrained redox responses to produce power. It is made up of two distinct half-cells. A half-cell is made out of a cathode (a piece of metal, M) inside an answer containing Mn+ particles in which M is any erratic metal.

A voltaic cell produces power as a redox response happens. The half reaction reduction potentials can be used to determine a voltaic cell voltage. Batteries are made from voltaic cells and are a convenient way to get electricity.

Incomplete question :

A Voltaic Cell Is Based On The Reduction Of Ag+(Aq) To Ag(S) And The Oxidation Of Sn(S) To Sn2+(Aq). (A) Write Half-Reactions For the cell's anode. include the phases of all species in the chemical equation.

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Explanation:

\(\huge{\underbrace{\overbrace{\mathfrak{\pink{Answer:}}}}}\)

Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products. These reactions lower the temperature of their surrounding area, thereby creating a cooling effect. Physical processes can be endothermic as well – Ice cubes absorb heat energy from their surroundings and melt to form liquid water (no chemical bonds are broken or formed).

When a chemical bond is broken, it is usually accompanied by a release of energy. Similarly, the formation of chemical bonds requires an input of energy. The energy supplied/released can be of various forms (such as heat, light, and electricity). Endothermic reactions generally involve the formation of chemical bonds through the absorption of heat from the surroundings. On the other hand, exothermic reactions involve the release of heat energy generated from bond-breakage.

Endothermic Reaction Examples

Ammonium nitrate (NH4NO3), an important component in instant cold packs, dissociates into the ammonium cation (NH4+) and the nitrate anion (NO3–) when dissolved in water

The atom economy of method 1 is 17%

Titanium is a valuable and expensive metal with some unique properties that make it suitable for special purposes.

Titanium is the perfect material for marine and aerospace applications because it has high corrosion resistance, especially in saltwater settings. Additionally biocompatible, titanium does not react with living tissue.

We know that the formula for atom economy is;

Atom economy(%) = Mass of desired product/Mass of reactants * 100/1

Mass of desired product = 48 g

Mass of reactants = 80 + 142 + 12 + 48 = 282 g

Atom economy (%) = 48/282 * 100/1

= 17%

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The two equations are -Ca2+(aq) + 2Cl–(aq) + 2K+(aq) + CO32–(aq) →CaCO3(s) + 2K+(aq) + 2Cl–(aq)Net Ionic Equation: Ca2+(aq) + CO32–(aq) → CaCO3(Sonic Equation: Mg2+(aq) + SO42–(aq) + 2K+(aq) + 2OH–(aq) → Mg(OH)2(s) + 2K+(aq) + SO42–(aq)Net Ionic Equation: Mg2+(aq) + 2OH–(aq) → Mg(OH)2(s)

Aqueous solution is a type of solution in which a solute is dissolved in water. It is the most common type of solution, and is often referred to as a dilute solution. Aqueous solutions are aqueous because they are composed mainly of water molecules, which are polar molecules and can dissolve many other substances. Examples of aqueous solutions include salt water, sugar water, and vinegar.


1. Aqueous solutions of calcium chloride and potassium carbonate are mixed

Complete Equation: CaCl2(aq) + K2CO3(aq) → CaCO3(s) + 2KCl(aq)

Ionic Equation: Ca2+(aq) + 2Cl–(aq) + 2K+(aq) + CO32–(aq) → CaCO3(s) + 2K+(aq) + 2Cl–(aq)

Net Ionic Equation: Ca2+(aq) + CO32–(aq) → CaCO3(s)

2. Aqueous solutions of magnesium sulfate and potassium hydroxide are mixed

Complete Equation: MgSO4(aq) + 2KOH(aq) → Mg(OH)2(s) + K2SO4(aq)

Ionic Equation: Mg2+(aq) + SO42–(aq) + 2K+(aq) + 2OH–(aq) → Mg(OH)2(s) + 2K+(aq) + SO42–(aq)

Net Ionic Equation: Mg2+(aq) + 2OH–(aq) → Mg(OH)2(s)

Aqueous precipitation reactions occur when two aqueous solutions are mixed and a solid precipitate is formed. This happens when two soluble ionic compounds react to form an insoluble compound. The complete equation for a precipitation reaction shows the complete reactants and products, including the ions present in both the reactants and the products. The ionic equation shows the ions present in the reactants and products, and the net ionic equation shows only the ions that are involved in the reaction. In the two examples above, both reactions form a solid precipitate, and the net ionic equation shows that both reactions involve an exchange of ions to form the insoluble product.

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Answer:

c

Explanation:

yes

The change described in the process of reconstituting frozen orange juice is a physical change. A physical change refers to a transformation that affects one or more physical properties of a substance, such as its size, shape, or state, without altering its chemical composition.

Adding water to frozen orange juice to reconstitute it causes a change in its volume, but it does not create new substances or cause a chemical reaction. Therefore, it is considered a physical change. Other examples of physical changes include cutting an apple, melting ice, and boiling water.

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Answer:

D. by repeating trials during an experiment

Explanation:

chile its actually d

Explanation:

Answer:

p=nRT/V

v=nRT/P

n=PV/RT

t=PV/nR

Answer:

3rd one

Explanation:

I just took the test and got 100%

Answer:

2nd one

Explanation:

Took the test