the thermite reaction is performed using 8.6 g fe2o3 and 1.8 g powdered al metal. which reactant is in excess and by how much?

Explanation:

The energy imparted to an electron as it flows through a battery can be calculated using the equation:

E = qV

where E is the energy in joules, q is the charge of the electron in coulombs, and V is the voltage of the battery in volts.

One electron has a charge of approximately 1.6 x 10^-19 coulombs.

So, for a 8 V battery, the energy imparted to an electron can be calculated as:

E = (1.6 x 10^-19 C) * (8 V) = 1.28 x 10^-18 J

In attojoules, 1 attojoule is 10^-18 J, so:

E = 1.28 x 10^-18 J / (10^-18 J/attojoule) = 1.28 attojoules (to three significant figures).

The amount of energy required to evaporate a given number of moles of pentene is given by the formula:

ΔHvap = energy/mole Rearranging the formula gives:

Mol = Energy/ΔHvap Substituting the given values, we get:

mol = (88 J) / (29.82 kJ/mol) = 0.0029488 mol Rounding to the correct number of significant digits gives:

Moles = 0.003 Moles

Thus, 0.003 moles of pentene can be evaporated while supplying 88 J of energy.

What is evaporation?

When a liquid becomes a gas, this process is called evaporation. If you boil water in a pot, you can observe the evaporation. Evaporation is done in two ways:evaporation and boiling.  

What is the difference between vaporize and vaporize?

Evaporation is defined as a phase transition of a compound or element that occurs during the boiling or sublimation process. Evaporation is just a type of evaporation that normally occurs at temperatures below the boiling point.  

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Alcohol fermentation, also known as ethanol fermentation, is a process that starts with glucose and yields ethanol as the end product.

Ethanol fermentation is a biochemical process in which sugars such as glucose, fructose, and sucrose are converted into cellular energy and ethanol.

It is an anaerobic process, meaning it takes place in the absence of oxygen. The process involves the conversion of glucose into pyruvate, followed by the conversion of pyruvate into ethanol and carbon dioxide.
The glucose is first converted into pyruvate through glycolysis, a process that requires energy in the form of NAD+. During glycolysis, NAD+ is used to facilitate the conversion of glucose into pyruvate, and NADH is generated.
In the second step of ethanol fermentation, the pyruvate is converted into ethanol and carbon dioxide. This process is facilitated by enzymes called pyruvate decarboxylase and alcohol dehydrogenase, which require the energy from NADH to catalyze the reaction. As NADH is used, NAD+ is regenerated. This is important, as it allows glycolysis to continue in the absence of oxygen.
Overall, the process of alcohol fermentation starts with glucose and yields ethanol as the end product. It is an anaerobic process, meaning that it does not require oxygen

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If has an atomic mass of 68.926 amu, has an atomic mass of 70.925 amu, and the atomic mass of gallium is 69.723 amu, the percent abundance of 70Ga is 101.68%.

To find the percent abundance of an isotope, you need to determine its relative abundance compared to the total amount of the isotopes present. Here's how you can do it for the isotope 70Ga:

Calculate the fraction of 70Ga in the sample:

fraction of 70Ga = (mass of 70Ga) / (atomic mass of Gallium)

fraction of 70Ga = (70.925 amu) / (69.723 amu)

fraction of 70Ga = 1.0168

Convert the fraction to a percentage:

percentage of 70Ga = (fraction of 70Ga) * 100

percentage of 70Ga = (1.0168) * 100

percentage of 70Ga = 101.68%

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Short Tandem Repeat (STR) analysis uses nuclear science to test chemicals within the hair shaft.

What is nuclear science?

Atomic nuclei, their components, and interactions, as well as other types of nuclear matter, are all studied in the field of physics known as nuclear physics. Atomic physics, which examines the atom in its entirety, including its electrons, should not be confused with nuclear physics.

Hair microscopy is used to examine the end of a hair and determine whether it has a root in order to determine whether a human hair sample is suitable for nuclear DNA analysis. If so, the sample can be examined using a short tandem repeat (STR) analysis, a nuclear DNA testing method. It is not possible to send hair that has been shed without a root for this kind of testing, but the hair shaft can still be tested for mitochondrial DNA (mtDNA).

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No, 99% of Ca2+ cannot be precipitated by sulfate without precipitating Ag+.

Sulfate is an anion composed of sulfur and oxygen atoms, with the chemical formula SO4−2. It is a polyatomic anion that is the conjugate base of sulfuric acid, H2SO4. Sulfates are found in many natural minerals and in synthetic compounds. They are used in a variety of industrial applications, including in detergents, fertilizers, dyes, and pigments. Sulfates are also used in the production of paper, textiles, and pharmaceuticals. In addition to their industrial uses, sulfates are also released into the environment through natural processes, such as volcanic eruptions and weathering of rocks.

When Ca2+ and Ag+ are both present in a solution, they will both form insoluble sulfates, and the precipitation of Ca2+ will not be selective. The precipitation of either ion requires a large excess of sulfate ions to reach 99%.

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When steam (H₂O(g)) is added to the equilibrium mixture of H₂O(g), CO(g), H₂(g), and CO₂(g), it will affect the position of the equilibrium.

The reaction between CO and H₂ to form CO₂ and H₂O is exothermic, meaning that it releases heat, and is described by the following equation:

CO(g) + H₂(g) ⇔ CO₂(g) + H₂O(g)

When steam is added to the system, it will increase the concentration of H₂O(g), which acts as a reactant in the forward reaction and a product in the reverse reaction. This will shift the equilibrium towards the reactants (CO(g) and H₂(g)) to maintain a constant concentration of products. The addition of steam will decrease the concentration of CO₂(g) and H₂(g) and increase the concentration of CO(g) and H₂O(g).

This shift in the equilibrium position will cause the reaction to be more favorable towards the formation of CO and H₂O, which are the products of the reaction, rather than CO₂ and H₂, which are the reactants. This is because the equilibrium constant for the reaction (Kc) is proportional to the product of the concentrations of the products over the product of the concentrations of the reactants.

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The empirical formula of ibuprofen is C13H18O2.

Moles of carbon = 75.69⋅g / 12.011⋅g⋅mol ^−1 = 6.30⋅mol.

Moles of hydrogen = 8.80⋅g / 1.00794⋅g⋅mol ^−1 =8.73⋅mol.

Moles of oxygen = 15.51⋅g / 15.999⋅g⋅mol ^−1 =0.969⋅mol.

The empirical formula is the simplest whole number ratio defining constituent atoms in a species. So we double this trial formula to get;

C13H18O2

The empirical formula is a simple representation of the relative number of atoms of each element present in a chemical compound. It gives the lowest whole number ratio of atoms in a molecule. For example, the empirical formula of glucose is CH2O, which represents that there are 2 hydrogen atoms, 1 carbon atom, and 6 oxygen atoms in one molecule of glucose. The empirical formula is different from the molecular formula, which gives the exact number of atoms of each element in a molecule.

Empirical formulas are useful for determining the molecular structure of a compound based on its elemental composition. They can also be used to calculate the molecular formula by multiplying the coefficients in the empirical formula by a factor that gives the correct molecular weight.

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The metal ions in these compounds are formed by the two-electron oxidation of neutral metal atoms.

Oxidation is a chemical reaction in which an atom loses electrons to become positively charged. This process results in the formation of an oxidized species and a reduced species. In other words, one species loses electrons while the other gains electrons. The oxidized species is called the oxidant, and the reduced species is called the reductant. Oxidation can occur in both organic and inorganic compounds.

For example, the oxidation of iron in air produces iron oxide (rust). In biological systems, oxidation reactions are an essential part of cellular metabolism, providing energy for the organism. The process of oxidation is crucial for many biological and physical processes, but it is also important to control and prevent excessive oxidation, in order to maintain health and protect against disease.

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In the reaction having an excess of K and 0.43 mol Cl₂, the mass of KCI that will be produced is 64 grams.

In the reaction equation

K+ Cl₂ → KCI

We balance the reactions.

2K+ Cl₂ → 2KCI

1 mole of Cl₂ will give 2 moles of KCl

Because of that,

0.43 mol Cl2 will result from = 0.43 × 2 = 0.86 mol KCl.

Then the mass of KCl is:

Moles of KCl = 0.86 mol

Molar mass of KCl = 74.55 g/mol

So:

Moles = mass/molar mass

Mass of KCl = moles × molar mass

Mass of KCl = 0.86 × 74.55

Mass of KCl = 64 grams

So, the mass of KCl is 64 grams.

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4.39×10²³ atoms are present in  0.73 mol of Bromine. Bromine exists in a liquid form of state of matter.

Bromine was found in 1826 in the dregs (bitterns) from the production of sea salt in Montpellier by the French scientist Antoine-Jérôme Balard.

By running chlorine through with an aqueous phase of the leftovers containing magnesium bromide, he was able to release the element. The substance was distillated with manganese dioxide as well as sulfuric acid, resulting in crimson vapours that condensed into a black liquid which is bromine.

number of atom = mole ×6.022×10²³

                           = 0.73 ×6.022×10²³

                          =4.39×10²³

Therefore, 4.39×10²³ atoms are present in  0.73 mol of Bromine.

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Answer: When foods are sufficiently dehydrated, microorganisms cannot grow and foods will not spoil.

yes

The percentage of chloride in the unknown sample is approximately 15.93%.

To calculate the percentage of chloride in the unknown sample, you can use the mass of silver chloride obtained to determine the number of moles of chloride in the original sample, and then convert that to a percentage.

First, calculate the number of moles of silver chloride by dividing the mass by its molar mass:

0.7332 g / 143.32 g/mol = 0.00513 mol AgCl

Next, calculate the number of moles of chloride in the original sample by assuming a 1:1 ratio of chloride ions to silver ions in the reaction:

0.00513 mol AgCl * 1 Cl- / 1 Ag+ = 0.00513 mol Cl-

Finally, divide the number of moles of chloride by the mass of the original sample and multiply by 100 to convert to a percentage:

(0.00513 mol Cl- / 0.3221 g) * 100 = 15.93%

So, the percentage of chloride in the unknown sample is approximately 15.93%.

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The solubility of NaCl when a saturated solution of NaCl is formed by adding 500g of NaCl to 0.500l of water where the excess solid NaCl is filtered from the solution is 5.23.

Given the mass of NaCl (m1) = 500g

The volume of water (V) = 0.5L

The reduced mass of NaCl (m2) = 346.8g

Filtered from the solution, the excess solid NaCl is dried in an oven.

The mass of NaCl dissolved in water = m1 - m2 = 500 - 346.8 = 153.2g

The mass of NaCl that will dissolve in 1L of water is = 2 x 153.2 = 306.4g/dm³

58.5g/mole is The molecular weight of NaCl

The amount of a substance in mol that will dissolve in 1 L or 1 dm³ of solution is known as its solubility.

Solubility in (g/dm³)/molar mass equals solubility in (mol/dm³).

(mol/dm³) solubility = 306.4/58.5

5.23 mol/dm³ is the solubility in (mol/dm³)

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Dipoles occur when electrons are shared unequally between atoms in the same molecule due to a high difference in the electronegativity of the atoms involved.

Non-polar covalent bonds, polar covalent bonds, and ionic bonds are the three types of bonding that you need to be familiar with.

The electrons in non-polar covalent bonds are distributed equally among the atoms. The electrons are not distributed equally among the atoms in polar covalent connections. The electrons are transported in ionic connections.

Pauling's scale of electronegativity provides the values for electronegativity.  

Therefore, Dipoles occur when electrons are shared unequally between atoms in the same molecule due to a high difference in the electronegativity of the atoms involved.

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Answer:

c.The Sun’s rays are perpendicular to the Equator, causing 12 hours of daylight on both Northern and Southern Hemispheres.

The combustion reaction of butane gives carbon dioxide and water as written below:

[tex]\rm C_{4} H_{10} + 8O_{2} \rightarrow 4 CO_{2} + 8H_{2}O[/tex]

Similarly the reaction  between Zn and copper nitrate can be written as follows:

[tex]\rm 2 Zn +Cu(NO_{3})_{2} \rightarrow 2ZnNO_{3} + Cu[/tex]

The balanced equation  of a reaction shows the perfect stoichiometry of reactants and products. The number of each elements in the reactants must be equal to their number in the product side.

The crisscross method of the formula is written as giving the charge of the cationic part as the subscript to the anionic part and vice versa.

The remaining reactions can be completed as following :

[tex]\rm NaOH + KBr \rightarrow NaBr + KOH[/tex]

[tex]\rm2 Li + S_{2} \rightarrow 2 Li S[/tex]

Similarly the decomposition of water can be  written as:

[tex]\rm 2 H_{2}O \rightarrow H_{2} + O_{2}[/tex]

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When hydrochloric acid solution with a ph of 2 splashes in your eye we shoiuld:Use water to clean your eye. For at least 20 minutes, soak in pristine, lukewarm tap water. Use whichever of these methods takes the least time.

Step inside the shower and gently spray your forehead over the troubled eye. If both of your eyes are afflicted, you might also aim the stream at your nose's bridge. Keep the afflicted eye or eyes' lids open.

Turn your head to the side and lower it. Hold your afflicted eye's lids open while it is submerged in a softly flowing faucet. Use the eye-rinse station on the job site if you have access to one.

It could be ideal for young children to lie down in the bathtub or lean back over a sink. Pour water in a slow stream.

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According to stoichiometry, for every 6 moles of hydrogen 6 moles of water is produced.For every 2 moles of hydrogen 2 moles of water is produced.For every 5.67  moles of hydrogen 5.67 moles of water is produced.

It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.As the stoichiometry of hydrogen to water is 2:2 same number of moles of water will be produced as that of hydrogen, that is 2 and 5.67 moles respectively.

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The atomic radius and atomic weight of an element have no bearing on the theoretical density of its crystal structure.

What is atomic radius?
Atomic radius is the measure of the size of an atom. It is the distance from the center of the nucleus of an atom to the outermost shell of electrons. The atomic radius of an element is determined by the number of protons and electrons present in the atom. Generally, the atomic radius decreases across a period and increases down a group. This is because the number of protons and electrons increase down a group, thus, the outermost shell of electrons is held more tightly due to increased attraction from the nucleus.

The theoretical density of a crystal structure depends on the density of the elements that make up the structure, the number and arrangement of those atoms, and the size of the unit cell.

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This process is known as frost wedging or freeze-thaw weathering. It occurs when water gets into cracks and crevices in rocks and then freezes, expanding and eventually forcing the rock to split apart.

What is wedging?

Wedging is a technique used in woodworking to join two pieces of wood together. It is done by driving a wedge (usually a metal wedge) between the two pieces of wood. The wedge then forces the wood apart, creating a tight fit. This is a great way to connect two pieces of wood without the need for nails or screws. Wedging is a strong and durable joint, making it a popular choice for woodworking projects. It can also be used to create texture in a material, by creating a pattern of cracks. Wedging is a traditional technique that has been used by artisans and sculptors for centuries.

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The molar mass of HCl is 36.46 g/mol, and the molar mass of H₂O is 18.02 g/mol.

What is molar mass?

Molar mass is a physical attribute of a substance that is defined as the mass of a specific substance divided by its mole quantity. It is often represented in grammes per mole (g/mol). Molar mass is used to determine the mass of a specific material based on its molar quantity, or to determine the quantity of a specific substance based on its mass.

In order to calculate the number of moles of HCl required to produce 180. g of water, we must first calculate the number of moles of H2O that are produced. Since the molar mass of H₂O is 18.02 g/mol, we can divide 180. g by 18.02 to get the number of moles produced:

180. g / 18.02 g/mol = 10.00 moles of H₂O

Now, since the reaction is 1:1 (1 mole of HCl for 1 mole of H₂O), we can simply multiply the number of moles of H₂O produced (10.00 moles) by 1 to get the number of moles of HCl required:

10.00 moles H₂O × 1 mole HCl/1 mole H₂O = 10.00 moles HCl

Therefore, in order to produce 180. g of water, 10.00 moles of HCl are required.

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The molality of the solution is 0.756 mol/1.90 kg = 0.398 molal.

To calculate the molality of a solution, you must first calculate the moles of the solute present in the solution.

To do this, you must use the molar mass of the solute and the amount of solute present in the solution. In this case, the amount of solute is 151 g of calcium bromide. The molar mass of calcium bromide is 199.89 g/mol [1], so the number of moles of calcium bromide is 151/199.89 = 0.756 mol.

Next, we must calculate the mass of the solvent, which is 1.90 l of water. The density of water is 1.000 g/ml, so the mass of the solvent is 1.90 l x 1.000 g/ml = 1.90 kg.

Finally, we can calculate the molality of the solution using the formula molality = moles of solute/kg of solvent. In this case, the molality of the solution is 0.756 mol/1.90 kg = 0.398 molal.

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Sand is absolutely composed of small particles of silicon dioxide. Sand can be classified as ceramics.

The silicon dioxide is a compound. It is an oxide of Silicon. The oxide are formed by the reaction of an element with the oxygen. In silicon dioxide, the silicon reacts with two oxygen molecule to form silicon dioxide. So, the two elements present in the silicon dioxide would be silicon and oxygen.

Ceramics can be defined as inorganic non-metallic materials which harden at high temperatures. The atomic structure of ceramics can be crystalline, non-crystalline, or semi-crystalline.  However, most ceramics have a crystalline atomic structure.

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The given statement, "the phenolate ion will appear this color under acidic conditions" is false because phenolphthalein is itself an acid.

Generally phenolphthalein is often used as an indicator in acid–base titrations in a chemical lab. For this kind of application, phenolphthalein  turns colorless in acidic solutions and pink in basic solutions.

Basically phenolphthalein is defined as an indicator or a chemical which changes color depending on whether it mixes with an acid or a base. It often turns purple when it meets something basic, such as ammonia; and stays colorless when it meets an acid like vinegar or a neutral substance like water.

Hence, the given statement is false.

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The molar mass of C4H10 is 58.12 g/mol, and the molar mass of O2 is 32.00 g/mol. When these two reactants combine, the reaction produces 44.01 g of CO2 for each mole of C4H10 and O2. The percent yield for the reaction is 100.84%.

Molar mass is a measure of the mass of a single molecule of a substance and is expressed in units of grams per mole (g/mol). It is calculated by taking the sum of the atomic masses of each atom in the molecule, multiplied by the number of atoms of each kind in the molecule. For example, the molar mass of water (H2O) is 18.015 g/mol, which is calculated by adding the atomic masses of two hydrogen atoms (2 x 1.0079 g/mol) and one oxygen atom (16.00 g/mol). Molar mass is important in chemistry, as it is often used to calculate the number of moles of a substance. It can also be used to help determine the concentration of a solution, and to calculate the mass of an element or compound in a known volume.

balanced equation

2C4H10 + 15O2 -----> 8CO2 + 10H2O

from the balanced equation

15 mol of O2 is giving 8 mol of CO2 this is if you talk in terms of moles

where as if you talk in terms of grams

15 x 32 gr O2 is giveng 8 x 44 gr CO2

480 gr O2 is giving 352 gr CO2

6.49 gr O2 will give 6.49 x 352 / 480 = 4.759 gr of CO2 this is theretically from the equation

but actually he got 4.80 gr

now

% of yield = actual / thritical  x 100

= 4.80 / 4.76 x 100

= 100.84%

Thus, The percent yield for the reaction is 100.84%.

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The volume (in liters) of ethane gas at STP burned when 5259 KJ of heat is produced is 6.7 L

We shall begin our calculation by obtaining useful information from the balanced equation as shown below:

2C₂H₆(g) + 7O₂(g) -> 4CO₂(g) + 6H₂O(g) ΔH = -1559 KJ

From the balanced equation above,

1559 KJ of heat energy were obtained from 2 L of ethane, C₂H₆

With the above information, we shall determine the volume (in liters) of ethane, C₂H₆, needed to produce 5259 KJ of heat energy. Details below:

From the balanced equation above,

1559 KJ of heat energy were obtained from 2 L of ethane, C₂H₆

Therefore

5259 KJ of heat energy will be obtain from = (5259 × 2) / 1559 = 6.7 L of ethane, C₂H₆

Thus, the volume of ethane, C₂H₆ needed is 6.7 L

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Lower reaction rates result from higher activation energies.

What function does activation energy serve in chemical reactions?

Exothermic reactions, like all other chemical reactions, require activation energy to start. Reactants need activation energy to move together, overcome repellent forces, and start bond breaking.

The term "rate of reaction" or "reaction rate" refers to the speed at which reactants transform into products. The rate of a chemical reaction and its activation energy are closely related. Particularly, the higher the activation energy, the slower the chemical reaction will proceed. This is because molecules can only complete a reaction after overcoming the activation energy barrier.

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