100 POINTS AND BRAINLIST!




Question
Why does the sun appear so much larger and brighter than the other stars that are seen from Earth?
Responses

The sun is much larger than other stars. [A]

The sun appears only during the daytime. [B]

The sun is closer to Earth than other stars. [C]

The sun burns more brightly than other stars. [D]

The number of moles of [tex]MnO_2[/tex] required is  3.345 moles.

In the given reaction, the balanced equation shows that for every 4 moles of [tex]MnO_2[/tex], 4 moles of [tex]KMnO_4[/tex] are produced. Therefore, we can use the stoichiometry of the reaction to calculate the moles of [tex]MnO_2[/tex] and the moles of [tex]KMnO_4[/tex]

Given:

Mass of [tex]MnO_2[/tex] = 291 g

Molar mass of[tex]MnO_2[/tex] = 87 g/mol

To find the moles of [tex]MnO_2[/tex], we use the formula:

Moles = Mass / Molar mass

Moles of [tex]MnO_2[/tex] = 291 g / 87 g/mol = 3.345 mol

Now, since the stoichiometry of the reaction tells us that the ratio of [tex]MnO_2[/tex]to [tex]KMnO_4[/tex] is 4:4, we can conclude that 3.345 moles of [tex]MnO_2[/tex]will produce an equal number of moles of [tex]KMnO_4[/tex]

Therefore, the moles of [tex]KMnO_4[/tex] produced will also be 3.345 mol.

However, the question asks for the moles of NaOH, which is not directly related to the given reaction. We cannot determine the moles of NaOH based on the information provided.

To find the moles of NaOH, we would need additional information or another relevant equation that includes NaOH.

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The equations (C + O2 → C2O), C (4Cu + O2 → 2Cu2O), and D (2H2 + O2 → 2H2O) demonstrate the law of conservation of mass. Option B.

The law of conservation of mass states that in a chemical reaction, the total mass of the reactants is equal to the total mass of the products. Let's analyze each equation to determine if it demonstrates the conservation of mass:

A Mg + S → MgS2:

This equation does not demonstrate the conservation of mass. The reactants contain one magnesium atom and one sulfur atom, while the product contains one magnesium atom and two sulfur atoms.

The number of atoms on the left side is not equal to the number of atoms on the right side, violating the law of conservation of mass.

B C + O2 → C2O:

This equation demonstrates the conservation of mass. The reactants contain one carbon atom and two oxygen atoms, while the product contains two carbon atoms and two oxygen atoms. The number of atoms on the left side is equal to the number of atoms on the right side, satisfying the law of conservation of mass.

C 4Cu + O2 → 2Cu2O:

This equation demonstrates the conservation of mass. The reactants contain four copper atoms and two oxygen atoms, while the product contains four copper atoms and two oxygen atoms.

The number of atoms on the left side is equal to the number of atoms on the right side, satisfying the law of conservation of mass.

D 2H2 + O2 → 2H2O:

This equation demonstrates the conservation of mass. The reactants contain four hydrogen atoms and two oxygen atoms, while the product contains four hydrogen atoms and two oxygen atoms. The number of atoms on the left side is equal to the number of atoms on the right side, satisfying the law of conservation of mass.

E H2SO4 + Zn → 4ZnSO + H2:

This equation does not demonstrate the conservation of mass. The reactants contain one sulfur atom, while the products contain four sulfur atoms.

The number of atoms on the left side is not equal to the number of atoms on the right side, violating the law of conservation of mass. So Option B is correct.

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At the usual working conditions of 101.5 kPa and 21°C, the chemical oxygen generator system would generate roughly 220.84 litres of oxygen using 500 g of LiClO4.

We may use the ideal gas law and stoichiometry to calculate how many litres of oxygen are created by the chemical oxygen generator system employing 500 g of LiClO4.

We must first determine the moles of LiClO4. LiClO4 has a molar mass of approximately 106.39 g/mol. As a result, 4.704 mol of LiClO4 are produced from 500 g of LiClO4 using the formula: 500 g / 106.39 g/mol

We can see from the chemical equation that 1 mole of LiClO4 results in 2 moles of O2. 4.704 mol of LiClO4 will therefore result in:

2 mol O2 / 1 mol LiClO4 4.704 mol LiClO4 = 9.408 mol O2

The moles of O2 under the specified conditions must then be converted to volume. The ideal gas law, which goes as follows:

PV = nRT

Where:

P = pressure = 101.5 kPa

V = volume (in liters)

n = moles of gas = 9.408 mol

R = ideal gas constant = 8.314 J/(mol·K)

T = temperature = 21°C = 294 K (converted to Kelvin)

Rearranging the equation to solve for V:

V = (nRT) / P

V = (9.408 mol × 8.314 J/(mol·K) × 294 K) / (101.5 kPa × 1000 Pa/kPa)

Simplifying the units:

V = (9.408 × 8.314 × 294) / 101.5

V ≈ 220.84 liters

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To calculate the molarity of a solution, we need to determine the number of moles of the solute (Bal2) and then divide it by the volume of the solution in liters.

Given:

Mass of Bal2 = 413 g

Volume of solution = 750 ml = 0.75 L

1. Calculate the number of moles of Bal2:

First, we need to convert the mass of Bal2 to moles using its molar mass. The molar mass of Bal2 can be calculated by summing the atomic masses of boron (B) and iodine (I):

Molar mass of Bal2 = (atomic mass of B × 1) + (atomic mass of I × 2)

Molar mass of Bal2 = (10.81 g/mol × 1) + (126.90 g/mol × 2)

Molar mass of Bal2 = 10.81 g/mol + 253.80 g/mol

Molar mass of Bal2 = 264.61 g/mol

Now we can calculate the number of moles of Bal2:

Moles of Bal2 = Mass of Bal2 / Molar mass of Bal2

Moles of Bal2 = 413 g / 264.61 g/mol

Moles of Bal2 ≈ 1.561 mol

2. Calculate the molarity of the solution:

Molarity (M) = Moles of solute / Volume of solution (in liters)

Molarity (M) = 1.561 mol / 0.75 L

Molarity (M) ≈ 2.081 M

Therefore, the molarity of the solution is approximately 2.081 M.

The molarity of the solution is approximately 1.408 M as to calculate the molarity of a solution, one must need to know the number of moles of the solute and the volume of the solution in liters.

The molar mass of BaI₂ is:

Ba (barium) atomic mass = 137.33 g/mol

I (iodine) atomic mass = 126.90 g/mol

Molar mass of  BaI₂ = (Ba atomic mass) + 2 × (I atomic mass)

= 137.33 + 2 × 126.90

= 137.33 + 253.80

= 391.13 g/mol

Given that the mass of BaI₂ is 413 g,

Number of moles = Mass / Molar mass

= 413 g / 391.13 g/mol

= 1.056 moles

Volume of solution = 750 ml = 750/1000 = 0.75 L

Finally, one can calculate the molarity of the solution using the formula:

Molarity = Number of moles / Volume of solution

= 1.056 moles / 0.75 L

= 1.408 M

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Metamorphic rocks can be harder, less porous, and have crystals that can be lined, describing some of the ways in which metamorphic rocks differ from sedimentary rocks.

There are two different types of rocks: sedimentary rocks and metamorphic rocks. Igneous or sedimentary pre-existing rocks undergo changes under extreme heat and pressure to form metamorphic rocks. This process results in the recrystallization of minerals, leading to the formation of a new rock with distinct physical and chemical characteristics.

Therefore, the correct option is B.

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The molarity of the sucrose in the iced tea mixture prepared by dissolving  0.750 moles of sucrose in the 2.00 L of iced tea is

The following data were obtained from the question:

The molarity of the solution can be obtained as illustrated below:

Molarity of solution = mole / volume

Molarity of solution = 0.750 mole / 2 liters

Molarity of solution = 0.375 M

Thus, we can conclude from the above calculation that the molarity of the solution is 2.5 M

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Answer:

85.99 grams of AgCl will be formed.

Explanation:

To determine the grams of AgCl formed in the reaction, we need to consider the stoichiometry of the reaction between silver nitrate (AgNO3) and barium chloride (BaCl2):

AgNO3 + BaCl2 -> AgCl + Ba(NO3)2

The balanced equation shows that the molar ratio between AgNO3 and AgCl is 1:1. This means that 1 mole of AgNO3 produces 1 mole of AgCl.

Given:

Volume of BaCl2 solution = 1500 ml = 1.5 L

Molarity of BaCl2 solution = 0.400 M

First, we need to calculate the number of moles of BaCl2 present in the solution:

moles of BaCl2 = volume of BaCl2 solution * molarity of BaCl2 solution

= 1.5 L * 0.400 M

= 0.600 moles

Since the molar ratio between BaCl2 and AgNO3 is 1:1, the number of moles of AgNO3 needed for complete reaction is also 0.600 moles.

Now, using the molar mass of AgCl, which is 143.32 g/mol, we can calculate the grams of AgCl formed:

grams of AgCl = moles of AgNO3 * molar mass of AgCl

= 0.600 moles * 143.32 g/mol

= 85.99 grams

Therefore, by adding enough AgNO3 to react fully with the 1500 ml of 0.400 M BaCl2 solution, approximately 85.99 grams of AgCl will be formed.

From the uncompleted equation, we have:

LiOH + HBr ->

Since we have two ionic substance reacting, we can conclude that the type of reaction is double displacement reaction as the reaction will involve exchange of ions between the reacting species.

The products of the reaction can be obtained by balancing the equation. This is shown below:

LiOH + HBr ->

By exchange of ion, we have

LiOH + HBr -> LiBr + H₂O

Now, observing the equation, we can see that the equation is balanced.

Thus, the products of the reaction are LiBr and H₂O

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Answer: about 12.5 mL is the estimated volume of a solution containing 2.1 g of KOH with a concentration of 3.0 M.

If a teacher showed an animal to students on a field trip. The  tool will allow the students to best see the animal up close is the hand lens.

Option D is correct.

A hand lens is known as a magnifying glass  which is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle.

A hand lens  has two essential properties which are its focal length and its diameter.

The students will therefore require a hand lens to look up the animal close.

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#complete question:

A teacher showed this animal to students on a field trip. Which tool will allow the students to best see the animal up close? O A Tape measure O B Graduated cylinder O c. Notebook O D. Hand lens

Answer:

Exothermic Reaction

Product  = Calcium hydroxide + hydrogen

Explanation:

The boiling point of a solution is influenced by the presence of solute particles, which can cause a change in the boiling point compared to the pure solvent. This phenomenon is known as boiling point elevation.

The magnitude of boiling point elevation depends on the concentration of the solute and the nature of the solute particles. In general, the greater the concentration of solute particles, the greater the boiling point elevation.

Comparing a 0.5m sodium chloride (NaCl) solution to a 0.3m aluminum sulfate ([tex]Al_2(SO_4)_3[/tex]) solution, we can determine the relative boiling point elevation.

Sodium chloride (NaCl) dissociates into two ions in solution (Na+ and Cl-), while aluminum sulfate ([tex]Al_2(SO_4)_3[/tex])dissociates into three ions (2[tex]Al_3[/tex]+ and 3[tex]SO_4[/tex]2-). This means that the aluminum sulfate solution will have a greater concentration of solute particles per mole than the sodium chloride solution.

Therefore, the boiling point of the 0.5m sodium chloride solution will be lower than the boiling point of the 0.3m aluminum sulfate solution.

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The most likely option based on common knowledge is sunlight is reacting with waste gases produced by vehicles burning fossil fuels to produce photochemical smog.

Photochemical smog is a type of air pollution that is formed when sunlight reacts with pollutants released from vehicle exhaust and other sources, such as industrial emissions. This reaction produces a mixture of harmful chemicals, including ground-level ozone and various secondary pollutants.

However, it's important to note that a definitive answer would require specific information about the picture in question, as different scenarios may lead to different outcomes.

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Answer: A : 3

Explanation: 18 CO2 / 6 CO2 = 3 C6H12O6

Answer:

A = 3.

Explanation:

Here is how:

To determine the number of molecules of C6H12O6 (glucose) needed to produce 18 molecules of CO2, we need to consider the balanced chemical equation for the complete combustion of glucose:

C6H12O6 + 6O2 -> 6CO2 + 6H2O

From the balanced equation, we can see that 1 molecule of glucose (C6H12O6) produces 6 molecules of CO2. Therefore, we can set up a proportion to find the number of glucose molecules needed:

1 molecule of glucose produces 6 molecules of CO2

x molecules of glucose produce 18 molecules of CO2

Using the proportion:

1/6 = x/18

To solve for x, we can cross-multiply:

6x = 18

Dividing both sides by 6:

x = 3

Therefore, 3 molecules of C6H12O6 are needed to produce 18 molecules of CO2.

The following chemical equations must be balanced:

1. N2 + 3 H2 → 2 NH3

Type: Synthesis

2. 2 KClO3 → 2 KCl + 3 O2

Type: Single Replacement

3. 2 NaF + ZnCl2 → ZnF2 + 2 NaCl

Type- Decomposition

4. 2 AlBr3 + 3 Ca(OH)2 → Al2(OH)6 + 6 CaBr2

Type- Double Replacement

5. 2 H2 + O2 → 2 H2O

Type: Combustion

6. 2 AgNO3 + MgCl2 → 2 AgCl + Mg(NO3)2

Type: Synthesis

7. 2 Al + 6 HCl → 2 AlCl3 + 3 H2

Type: Decomposition

8. C3H8 + 5 O2 → 3 CO2 + 4 H2O

Type: Combustion

9. 2 FeCl3 + 6 NaOH → Fe2O3 + 6 NaCl + 3 H2O

Type: Double Replacement

10. 4 P + 5 O2 → 2 P2O5

Type: Synthesis

11. 2 Na + 2 H2O → 2 NaOH + H2

Type: Single Replacement

12. 2 Ag2O → 4 Ag + O2

Type: Decomposition

13. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Type: Combustion

14. 2 KBr + MgCl2 → 2 KCl + MgBr2

Type: Double Replacement

15. 2 HNO3 + Ba(OH)2 → Ba(NO3)2 + 2 H2O

Type: Double Replacement

16. C5H12 + 8 O2 → 5 CO2 + 6 H2O

Type: Combustion

17. 4 Al + 3 O2 → 2 Al2O3

Type: Synthesis

18. Fe2O3 + 2 Al → 2 Fe + Al2O3

Type: Single Replacement

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Answer:

a. P2O7 - This is a covalent compound. P and O have similar electronegativities and they form a covalent bond between them, rather than an ionic bond.

b. SnBr2 - This is a covalent compound. Sn and Br have different electronegativities, but they still form a covalent bond due to their relatively small difference in electronegativity.

c. Fe(OH)2 - This is an ionic compound. Fe has a higher electronegativity than O and H, so it tends to donate its electrons and become positively charged. This results in the formation of ionic bonds between Fe and OH.

d. Cl3O8 - This is a covalent compound. Cl and O have similar electronegativities, so they form covalent bonds rather than ionic bonds.

Answer:

The limiting reactant is BF3 because there is less of it than Li2SO4.

Explanation:

The following chemical equations must be balanced:

1. N2 + 3 H2 → 2 NH3

Type: Synthesis reaction

2. 2 KClO3 → 2 KCl + 3 O2

Type: Single Replacement reaction

3. 2 NaF + ZnCl2 → ZnF2 + 2 NaCl

Type- Decomposition reaction

4. 2 AlBr3 + 3 Ca(OH)2 → Al2(OH)6 + 6 CaBr2

Type- Double Replacement reaction

5. 2 H2 + O2 → 2 H2O

Type: Combustion reaction

6. 2 AgNO3 + MgCl2 → 2 AgCl + Mg(NO3)2

Type: Synthesis reaction

7. 2 Al + 6 HCl → 2 AlCl3 + 3 H2

Type: Decomposition reaction

8. C3H8 + 5 O2 → 3 CO2 + 4 H2O

Type: Combustion reaction

9. 2 FeCl3 + 6 NaOH → Fe2O3 + 6 NaCl + 3 H2O

Type: Double Replacement reaction

10. 4 P + 5 O2 → 2 P2O5

Type: Synthesis reaction

11. 2 Na + 2 H2O → 2 NaOH + H2

Type: Single Replacement reaction

12. 2 Ag2O → 4 Ag + O2

Type: Decomposition reaction

13. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Type: Combustion reaction

14. 2 KBr + MgCl2 → 2 KCl + MgBr2

Type: Double Replacement reaction

15. 2 HNO3 + Ba(OH)2 → Ba(NO3)2 + 2 H2O

Type: Double Replacement reaction

16. C5H12 + 8 O2 → 5 CO2 + 6 H2O

Type: Combustion reaction

17. 4 Al + 3 O2 → 2 Al2O3

Type: Synthesis reaction

18. Fe2O3 + 2 Al → 2 Fe + Al2O3

Type: Single Replacement reaction

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Based on the given reaction, the acid-base pairs in this reaction are:

An acid-base pair refers to a set of two chemical species that are related through the transfer of a proton (H+ ion) during a chemical reaction.

One species acts as an acid by donating a proton, while the other acts as a base by accepting that proton.

In the given reaction:

HCO₃⁻ (aq) + NH₃ (aq) → NH₄⁺ + CO₃²⁻

An acid-base pair can be identified as follows:

HCO₃⁻ (bicarbonate ion) can act as an acid by donating a proton (H⁺), becoming CO₃⁻.

NH₃ (ammonia) can act as a base by accepting a proton (H⁺), becoming NH₄⁺ (ammonium ion).

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The concentration of ethanol in units of volume/volume percent is 29.49%.

To calculate the concentration of ethanol in units of volume/volume percent, we need to determine the volume of ethanol relative to the total volume of the solution.

Total volume of the solution = volume of water + volume of ethanol

Total volume = 569 mL + 238 mL

Total volume = 807 mL

To express the concentration as volume/volume percent, we can calculate the ratio of the volume of ethanol to the total volume of the solution and multiply by 100 to obtain a percentage.

Concentration of ethanol = (volume of ethanol / total volume of solution) x 100

Concentration of ethanol = (238 mL / 807 mL) x 100

Concentration of ethanol = 0.2949 x 100

Concentration of ethanol = 29.49%

Therefore, the concentration of ethanol in the solution is approximately 29.49%.

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The name of LiBr is lithium bromate and the charge of the cation (K) is +.

A cation is a positively charged ion, i.e. one that would be attracted to the cathode in electrolysis. The opposite of a cation is an anion.

Cations and anions make up an ionic compound and determine the charge on the compound. For example, an ionic compound; Lithium bromate is given in this question.

Lithium bromate is made up of Lithium (Li+) as the cation and chlorine (Cl-) as the anion.

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Answer:

Overall, energy is released in exothermic and absorbed in endothermic reactions. Therefore, "a" is the correct statement. The other statements are all incorrect.

Explanation:

u suck

The solubility chart provides information about the solubility of various compounds in water. Here are the solubilities of the given compounds:

a. (NH₄)₂CO₃: According to the solubility chart, most carbonate (CO₃²⁻) salts are insoluble, except for those of Group 1 metals (alkali metals) and ammonium (NH₄⁺). Therefore, (NH₄)₂CO₃ is soluble.

b. Fe(OH)₂: Hydroxide (OH⁻) salts of transition metals, including iron (Fe), are generally insoluble, except for those of Group 1 metals and ammonium. Therefore, Fe(OH)₂ is insoluble.

c. Ca(OH)₂: Calcium hydroxide (Ca(OH)₂) is soluble. However, the given compound "CaOH" appears to be missing the subscript ₂, indicating two hydroxide ions. If it should be Ca(OH)₂, then it is soluble.

d. PbCl₂: According to the solubility chart, chloride (Cl⁻) salts, including lead chloride (PbCl₂), are generally soluble, except for those of silver (Ag⁺), lead (Pb²⁺), and mercury (Hg₂²⁺). Therefore, PbCl₂ is insoluble.

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To calculate the molarity of the solution, we need to know the number of moles of BaI2 and the volume of the solution in liters.

First, let's calculate the number of moles of BaI2. We can use the formula:

Number of moles = Mass (in grams) / Molar mass

The molar mass of BaI2 can be calculated as follows:

Ba: atomic mass = 137.33 g/mol

I: atomic mass = 126.90 g/mol

2 x I = 2 x 126.90 g/mol = 253.80 g/mol

Total molar mass of BaI2 = 137.33 g/mol + 253.80 g/mol = 391.13 g/mol

Number of moles of BaI2 = 413 g / 391.13 g/mol ≈ 1.056 moles

Next, we need to convert the volume of the solution from milliliters to liters:

Volume of solution = 750 ml / 1000 = 0.75 L

Finally, we can calculate the molarity using the formula:

Molarity = Number of moles / Volume of solution

Molarity = 1.056 moles / 0.75 L ≈ 1.408 M

Therefore, the molarity of the BaI2 solution is approximately 1.408 M.

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Answer:

the water arrives on the earth in the form of water rich objects(planetesimals)

Answer:

[tex]\huge\boxed{\sf CNH_4}[/tex]

Explanation:

Given compound us,

C₂N₂H₈

= 2 : 2 : 8

= 2 ÷ 2 : 2 ÷ 2 : 8 ÷ 2

= 1 : 1 : 4

So, we can write the formula as:

[tex]\rule[225]{225}{2}[/tex]