How is it possible for scientists to know the composition of stars without traveling to the star?

Answer: mass of water is 81.1 g

Explanation: from reaction eguation you see there are equal amounts of water and Mg(OH)2. Then amount of water is 4.50 mol. Molar mass of water is 18.016 g/mol.

Mass m= n·M= 4.50 mol· 18.016 g/mol = 81.1 g

The number of grams of water reacting to form a mass of water is 81.1 g.

Mass is the quantity of matter in a physical body.

The given reaction is

MgO(s) + H₂O(1) → Mg(OH)₂(s)

The number of moles is equal in both sides

The moles of water is 4.50

The molar mass of water is 18.016 g/mol

mass × molar mass

4.50 × 18.016 = 81.1 g.

Thus, the number of grams of water reacting to make a mass of water is 81.1 g.

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Answer:

I'm not sure if this is true but in science class I learned that stress can cause a risk of diseases

Explanation:

the more months of stress you have, the higher the risk

By performing the necessary calculations for each case, we can determine the pH values for (a), (b), (c), (d), and (e) in the titration of HClO with KOH.

(a) Before the addition of any KOH, the solution contains only HClO. To calculate the pH, we need to consider the ionization of HClO. HClO is a weak acid, and its ionization can be determined using its ionization constant. By using the ionization constant and the initial concentration of HClO, we can calculate the concentration of H+ ions and convert it to pH.

(b) After adding 25.0 mL of KOH, a neutralization reaction occurs between HClO and KOH. The moles of HClO and KOH are now equal, and the solution contains the resulting salt. We can determine the concentration of OH- ions based on the amount of KOH added and calculate the pOH. From pOH, we can obtain the pH by subtracting it from 14.

(c) After adding 35.0 mL of KOH, the solution is still in excess of HClO. We need to determine the remaining moles of HClO and the resulting concentration of H+ ions to calculate the pH.

(d) After adding 50.0 mL of KOH, the moles of HClO and KOH become equal. The solution contains only the salt resulting from the neutralization reaction. We can calculate the concentration of OH- ions and convert it to pOH and then pH.

(e) After adding 60.0 mL of KOH, the solution is in excess of KOH. We need to determine the excess moles of KOH and calculate the concentration of OH- ions to obtain the pOH and pH.

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The reduction of iodate by hydrogen sulfite ions to give iodide and sulfate in basic aqueous solution is represented by the following equation:
IO3– + 3HSO3– + H2O → 3SO4^2– + I– + 2H+ + 2H2O

The balanced equation is:

2 IO3– + 6 HSO3– + 6 OH– → 6 SO4^2– + 2 I– + 9 H2O

To balance the given redox reaction, we follow these steps: Write the unbalanced chemical equation for the given reaction. Split the reaction into two half-reactions: oxidation and reduction.Balance the atoms that are not hydrogen or oxygen in each half-reaction. This is done by adding the appropriate coefficient to each species.Write balanced equations for each half-reaction.Combine the half-reactions to get a balanced overall equation.In the given reaction, iodate (IO3–) is reduced to iodide (I–) by hydrogen sulfite ions (HSO3–) to give sulfate (SO4^2–) in basic aqueous solution. The unbalanced chemical equation is:

IO3– + HSO3– → I– + SO4^2–

Step 2: We split the reaction into two half-reactions:'

Oxidation half-reaction: IO3– → I–

Reduction half-reaction: HSO3– → SO4^2–

Step 3: We balance the atoms that are not hydrogen or oxygen in each half-reaction. We see that the oxidation half-reaction is already balanced and we balance the reduction half-reaction as follows:

HSO3– → SO4^2– + 2 H+ + 2 e–

Step 4: We write balanced equations for each half-reaction.

IO3– + 6 H+ + 5 e– → I– + 3 H2O

HSO3– → SO4^2– + 2 H+ + 2 e–

Step 5: We combine the half-reactions to get a balanced overall equation.

IO3– + 6 HSO3– + 6 OH– → 6 SO4^2– + 2 I– + 9 H2O

Thus, the balanced equation is:

2 IO3– + 6 HSO3– + 6 OH– → 6 SO4^2– + 2 I– + 9 H2O

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On completing and balancing the half-reaction of chromium (iii) forming from dichromate the number of electrons are either produced or consumed  are option (b): Three electrons are produced.

To determine the number of electrons produced or consumed in the half-reaction of chromium(III) forming from dichromate, let's first write the balanced half-reaction. The dichromate ion (Cr2O7^2-) is reduced to chromium(III) ion (Cr^3+) in this reaction. We can represent the reduction half-reaction as follows:

Cr2O7^2- ⟶ Cr^3+

To balance the half-reaction, we need to equalize the number of chromium atoms and oxygen atoms on both sides. Since there are two chromium atoms on the left side and only one on the right side, we add a coefficient of 2 in front of the chromium ion:

2Cr2O7^2- ⟶ 2Cr^3+

Now, let's examine the changes in oxidation state for chromium in this reaction. In dichromate (Cr2O7^2-), chromium has an oxidation state of +6, while in chromium(III) (Cr^3+), it has an oxidation state of +3. Therefore, the oxidation state of chromium decreases by 3 in this reduction half-reaction.

Reduction involves a gain of electrons. Since the oxidation state of chromium decreases by 3, it means that three electrons are gained by each chromium ion. Therefore, the correct answer is option (b): Three electrons are produced.

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Answer:

c. Six electrons are consumed

Explanation:

The first step is to ensure that the chromium atoms are balanced by adjusting the coefficients if needed. Do so by giving the Cr3+ ion a coefficient of 2.

Cr2O2−7 ⟶ 2Cr3+ (aq)

Next, balance the oxygen atoms by adding H2O molecules. The half-reaction has seven O atoms on the left and none on the right, so add 7H2O (l) to the right side.

Cr2O2−7 ⟶ 2Cr3+ (aq) + 7H2O (l)

Next, balance the hydrogen atoms by adding H+ ions. The half-reaction has 14 H atoms on the right side and none on the left, so add 14H+(aq) to the left side.

Cr2O2−7 + 14H+ (aq) ⟶ 2Cr3+ (aq) + 7H2O (l)

At this point, the charge can be balanced by adding electrons (e−). To do so, find the total charge on each side of the reaction. The left side has a total charge of (−2) + 14 × (+1) = 12+. The right side has a total charge of 2 × (+3) = 6+. Adding 6e− to the left side brings the charge down to 6+ to match the right side.

Cr2O2−7 + 14H+ (aq) +6e− ⟶ 2Cr3+ (aq) + 7H2O (l)

This gives us the answer to the question, which is that six electrons are consumed, since they are on the left side of the equation. Note that it does not make a difference whether the reaction is assumed to be in an acidic or a basic solution. The extra step taken for a basic solution is to add the same number of OH− ions to both sides of the reaction, which does not affect the number of electrons needed to balance the charges.

Answer:

4.8x10⁻³ Liters are required

Explanation:

Molarity is an unit of concentration in chemistry defined as the ratio between moles of solute (In this case, silver nitrate) and liters of solution.

The 0.50M solution contains 0.50 moles of silver nitrate per liter of solution.

To provide 2.4x10⁻³ moles Silver nitrate are required:

2.4x10⁻³ moles * (1L / 0.50 moles) =

Answer:

2

Explanation:

i dont andesdant

The experimental volume of the flask is found  to be incorrect as the  volume labeled on the flask is not an accurate measure of the total volume of the flask as it will result in errors.

Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.

There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.

Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.

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Human use of land has negative impacts. Human activities contribute to the erosion and pollution of beaches. Deforestation of land can also lead to desertification and a loss of biodiversity.

Answer:

C. The Pressure

Explanation:

Pressure only affects the solubility of gases. It barely affects the solubility of solids and liquids.

Answer:

a. Indivisible.

b. Mass.

c. Masses.

d. Compound.

e. Elements.

Explanation:

An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such defines the structure of a chemical element.

Generally, these atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.

Hence, all the physical properties of a mineral result from the mineral's internal arrangement of atoms.

The following are statements postulated by the Dalton's atomic model;

a) Elements are composed of minute, indivisible particles called atoms.

b) Atoms of the same element are alike in mass and size.

c) Atoms of different elements have different masses and sizes.

d) Chemical compound are formed by the union of two or more different atoms of different elements.

e) Atoms combine to form compounds in simple numerical ratios, such as one to one, one to two, etc.

f) Atoms of two elements may combine in different ratios to form more than one compound.

For the central boron atom:

The central boron atom:

A. Obeys the octet rule.

In the Lewis structure of BF3, boron (B) is the central atom bonded to three fluorine (F) atoms. Boron has an atomic number of 5 and its electronic configuration is 1s² 2s² 2p¹. In its ground state, boron has three valence electrons. In BF3, each fluorine atom shares one electron with boron to form a single bond, resulting in three single bonds between boron and fluorine.

Since boron only forms three single bonds and has no lone pairs of electrons, it satisfies the octet rule. The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable electron configuration with eight electrons in their valence shell, similar to the nearest noble gas. Therefore, the central boron atom in BF3 obeys the octet rule.

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The equilibrium constant for the reaction D ⇌ A + 2B is approximately 0.3038.

The equilibrium constant, K, for the reaction D ⇌ A + 2B is calculated from the equilibrium constants of the individual reactions and from the principle of multiplying and dividing equilibrium constants.

Given the reactions and their equilibrium constants:

A + 2B ⇌ 2C with K1 = 2.45

2C ⇌ D with K2 = 0.124

To obtain the equilibrium constant for the desired reaction, we can multiply the equilibrium constants of the individual reactions:

K = K1 * K2

K = 2.45 * 0.124

K = 0.3038

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Answer:

When a guy who shows a girl to much emotion, they get turned off.

Explanation:

When mentos and diet coke are mixed, the diet soda explodes

Explanation:

Due to the fact that the mentos are dense, they sink to the bottom of the bottle which gives the diet coke its explosion.

Answers & Explanations:

What happens when Mentos and Diet Coke are mixed?

Mentos sinks rapidly through the liquid, causing a fast, large eruption.

What causes Mentos and Diet Coke to react that way?

The addition of the Mentos leads to the rapid nucleation of carbon dioxide gas bubbles in the Diet Coke, causing them to precipitate out of the solution.

Is the reaction Chemical or Physical?

The eruption is caused by a physical reaction.

How could we prove one way or the other?

We can prove it by using the equation:

[tex]CO_{2} (aq) = Co_{2}(g)[/tex]

Answer:

500mL.

Explanation:

Answer:

Acids: react with metals, taste sour

Both: can cause burns, conduct electricity

Basis: react with nonmetals, taste bitter

Explanation:

This is the right answer

Answer:

Acids: react with metals, taste sour

Both: can cause burns, conduct electricity

Basis: react with nonmetals, taste bitter

it's right, I did it.

The compound CH3CH2COCH2CH2CH3 is named as 3-hexanone.

The given condensed structural formula represents a ketone called 3-hexanone. In the IUPAC nomenclature, the position of the carbonyl group (C=O) is indicated by the lowest possible number, which in this case is 3. The carbon chain consists of six carbon atoms (hexane) with a carbonyl group attached to the third carbon atom.

The compound 3-hexanone can undergo both oxidation and reduction reactions. As a ketone, it contains a carbonyl group that can be oxidized to form a carboxylic acid or reduced to form an alcohol. Therefore, it is not limited to only oxidation or reduction reactions.

The statement that the compound can be reduced to form 3-hexene is incorrect. Reduction of 3-hexanone would yield 3-hexanol, not 3-hexene. Reduction adds hydrogen to the carbonyl group, converting it to a hydroxyl group (-OH).

The compound with the condensed structural formula CH3CH2COCH2CH2CH3 is named 3-hexanone. It is a ketone that can undergo both oxidation and reduction reactions. However, it cannot be directly reduced to form 3-hexene; instead, reduction of 3-hexanone would yield 3-hexanol. The compound can be formed by the oxidation of 3-hexanol, where the alcohol group is converted to a carbonyl group.

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When Br2(l) boils at its normal boiling point, its entropy increases. Entropy is a measure of the disorder or randomness in a system, and boiling represents a transition from a more ordered liquid phase to a more disordered gaseous phase.

During boiling, the intermolecular forces holding the liquid Br2 molecules together are overcome, and the molecules gain enough energy to escape into the gas phase. In the gaseous phase, the molecules have greater freedom of movement and occupy a larger volume compared to the liquid phase. This increase in molecular motion and expansion of volume contributes to an increase in the disorder or randomness of the system, leading to an increase in entropy. The concept of entropy can also be understood from a statistical perspective. In the liquid phase, the molecules are more closely packed and have limited freedom of movement. However, in the gaseous phase, the molecules are dispersed and have a larger number of possible positions and velocities. This increased number of microstates in the gaseous phase corresponds to a higher probability distribution, which is a characteristic of higher entropy.

Therefore, when Br2(l) boils at its normal boiling point, its entropy increases as the system transitions from a more ordered liquid phase to a more disordered gaseous phase.

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The following reactions are redox reactions are,

a. 4K(s) + O2(g) → 2K2O(s)

b. Al(s) + 3Ag+(aq) → Al3+(aq) + 3Ag(s)

d. SO3(g) + H2O(l) → H2SO4(aq)

Redox (shorthand for reduction/oxidation reaction) reactions are chemical reactions in which the oxidation state of atoms is changed.

These reactions are the basis for batteries, fuel cells, and other energy storage devices, and they also play a crucial role in the metabolic processes of living organisms.

Example of a Redox reaction,

Al(s) + 3Ag+(aq) → Al3+(aq) + 3Ag(s)

In the above reaction, Al metal is oxidized (loses electrons) and Ag+ ions are reduced (gains electrons).

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Answer:

The answer of this question is A

Answer: B is the right

Explanation:

Answer:

1. Compress.

2. Fixed.

3. Melts.

4. Melting point.

5. Freezing point.

6. High.

7. Crystalline.

8. Lattice.

9. Unit cell.

10. Amorphous.

Explanation:

In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are;

1. Gas: it is the state of matter in which the physical substance has no definite shape or volume and as a result fills all available space. Also, gases are easily compressible and can flow. Examples of gases are hydrogen, oxygen, argon, nitrogen etc.

2. Liquid: it is the state of matter in which the physical substance can be poured and it takes the shape of its container. Also, liquids generally have a definite volume. Examples of liquids are urine, water, milk, blood etc.

3. Solid: it is the state of matter in which the physical substance has a definite shape and fixed volume but not compressible. Examples of solids are pen, screwdriver, television, car etc.

Filling the missing words (texts) of the question, we have;

Solids tend to be dense and difficult to compress. They do not flow or take the shape of their containers, like liquids do, because the particles in solids vibrate around fixed points. When a solid is heated until its particles vibrate so rapidly that they are no longer held in fixed positions, the solid melts. The melting point is the temperature at which a solid changes to a liquid. The melting and freezing point of a substance are at the same temperature. In general, ionic solids tend to have relatively high melting points, while molecular solids tend to have relatively low melting points. Most solids are crystalline. The particles are arranged in a pattern known as a crystal lattice. The smallest subunit of a crystal lattice is the unit cell. Some solids lack an ordered internal structure and are called amorphous solids.

The energy change associated with the transition from n = 2 to n = 5 in a hydrogen atom is determined using the formula:ΔE = -RH [(1/nf²) - (1/ni²)]where RH is the Rydberg constant, nf is the final energy level (n = 5), and ni is the initial energy level (n = 2).

The Rydberg constant (RH) is a fundamental physical constant relating to the electromagnetic spectra of atomic hydrogen, or the spectrum of a one-electron ion.

The Rydberg constant is defined as the wave number of the first spectral line of atomic hydrogen, i.e., 1.09678 × 107 m-1. Substituting the values into the formula: ΔE = -RH [(1/5²) - (1/2²)]ΔE = -2.179 × 10^-18 J = -13.6 eV.

Therefore, the energy change associated with the transition from n = 2 to n = 5 in a hydrogen atom is -2.179 × 10^-18 Joules or -13.6 electron-volts. This energy corresponds to the energy of the photon that is emitted or absorbed during the transition between the two energy levels.

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Explanation:

M&M's.

Reese's Peanut Butter Cups.

Hershey Bar.

Snickers.

Kit Kat.

Twix.

Twizzlers.

Skittles.

The resulting solution formed by the dissolving of sodium acetate in water is basic because C2H3O2 is the conjugate base of a weak acid.

When sodium acetate (NaC2H3O2) is dissolved in water, it dissociates into sodium ions (Na+) and acetate ions (C2H3O2-). Acetate ions act as the conjugate base of acetic acid (CH3COOH), which is a weak acid.

In water, acetate ions can accept protons from water molecules through hydrolysis to a small extent, resulting in the formation of hydroxide ions (OH-) and acetic acid. This reaction is a weak base reaction:

C2H3O2- + H2O ⇌ CH3COOH + OH-

The presence of hydroxide ions (OH-) in the solution makes it basic. The basic nature of the solution is primarily due to the hydrolysis of the acetate ions, which generate hydroxide ions, rather than the sodium ions (Na+) which do not significantly affect the pH.

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Reactants in the reaction are [tex]H_2O_2[/tex](aq),[tex]I^-[/tex](aq); Products are[tex]IO^-[/tex](aq), [tex]H_2O[/tex](l), [tex]O_2[/tex](g); Intermediate are [tex]IO^-[/tex]aq); and catalysts are None.

The first step of the mechanism is the rate-determining step. In this step, a hydrogen atom from hydrogen peroxide is transferred to an iodine ion, forming an intermediate called iodosyl ion. The iodosyl ion is then unstable and decomposes to form oxygen gas and another iodine ion.

The overall reaction is:

[tex]H_2O_2(aq) + I^-(aq) - > IO^-(aq) + H_2O(l) + O_2(g)[/tex]

The reactants are hydrogen peroxide and iodine ion. The products are iodosyl ion, water, and oxygen gas. The intermediate is iodosyl ion. There is no catalyst in this mechanism.

The rate-determining step is the slowest step in the mechanism. This is the step that determines the overall rate of the reaction. In this case, the rate-determining step is the step in which the hydrogen atom is transferred from hydrogen peroxide to iodine ion.

The intermediate is a chemical species that is formed in one step of the mechanism and is consumed in another step. In this case, the intermediate is iodosyl ion. It is formed in the first step of the mechanism and is consumed in the second step.

The catalyst is a chemical species that speeds up the rate of a reaction but is not consumed in the reaction. There is no catalyst in this mechanism.

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The statement "Reaction of heating potassium permanganate produces potassium manganate" is false.

The reaction of heating potassium permanganate (KMnO₄) does not produce potassium manganate (K₂MnO₄). Instead, it undergoes a thermal decomposition reaction, resulting in the formation of different products.

When heated, potassium permanganate decomposes into potassium manganate (K₂MnO₄), manganese dioxide (MnO₂), and oxygen gas (O₂).

The reaction can be represented as follows:

2 KMnO₄(s) → K₂MnO₄(s) + MnO₂(s) + O₂(g)

Therefore, heating potassium permanganate leads to the formation of potassium manganate, along with manganese dioxide and oxygen gas. The color change from purple to green observed during the reaction is due to the formation of potassium manganate.

However, it is important to note that potassium manganate is not the sole product of the reaction but one of the products alongside manganese dioxide and oxygen gas.

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Complete question :

Reaction of heating potassium permanganate produces potassium manganate. T/F

The final temperature of the water mixture can be determined using the principle of conservation of energy.

When the two bodies of water are mixed, the heat lost by the hotter water is equal to the heat gained by the colder water.

The summary of the answer is: The final temperature of the water mixture is closest to 30°C.

To explain further, we can use the equation for heat transfer:

q = m * c * ΔT

Where:

q = heat transferred

m = mass of the substance

c = specific heat capacity

ΔT = change in temperature

For the hot water:

q1 = m1 * c * ΔT1

For the cold water:

q2 = m2 * c * ΔT2

Since the total heat transferred is zero (insulated cup), we have:

q1 + q2 = 0

m1 * c * ΔT1 + m2 * c * ΔT2 = 0

Plugging in the given values:

so * c * (40 - T) + 30 * c * (T - 20) = 0

Simplifying the equation and solving for T, we find:

10 * T = 400

T ≈ 40°C / 10 = 40°C / 10 = 4°C

Therefore, the final temperature of the water mixture is closest to 30°C.

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