Be sure to answer all parts. A student is given four solid samples labeled W, X, Y, and Z. All have a metallic luster. She is told that the solids could be gold, lead sulfide (PbS), quartz which is SiO2, and iodine. The results of her investigations are: (a) W is a good electrical conductor; X, Y, and Z are poor electrical conductors. (b) When the solids are hit with a hammer, W flattens out, X shatters into many pieces, Y is smashed into a powder, and Z is not affected. (c) When the solids are heated with a Bunsen burner, Y melts with some sublimation, but X, W, and Z do not melt. (d) In treatment with 6 MHNO3, X dissolves; there is no effect on W, Y, or Z. On the basis of these test results, identify the solids. Sample W Au PbS SiO2 Sample X: Au PbS Sample X: Au PbS SiO2 I, Sample Y: Au PbS SiO2 I2 Sample Z: Au PbS Au PbS SiO2 Sample Z: Au PbS SiO2

Answer:

16 moles

Explanation:

Since we have the ratios of the substances' molar masses, we can just calculate using those. We know that our end product has 3 grams of oxygen; our equation shows that the end product has 3O2 after decomposition, so we can compare how much oxygen we have to how much 3O2 would weigh if we had whole moles of substance.

3O2 would be six moles and weigh 96 grams. Since we only actually have 3 grams, we know that we are working with 3 / 96 = 1/32 of a mole per substance. Now, we look at the equation again, and multiply the ratio of each substance by 1/32, and then by the molar weight. All that's left is finding the importance of the Sodium and the Chlorine, both of which are prevalent in a ratio of 2, so we take 2/32=1/16 of each substance and multiply by their molar weights; 23/16 grams of Sodium, and 35.5/16 grams of Chlorine. Adding those together, we have 58.5/16 grams, which we can round to 64/16, or 4. Adding those 4 grams to the 3 grams of oxygen that the problem gives us, we have seven grams of Sodium Chlorate necessary to give us 3 grams of oxygen post-decomposition.

Answer:

Explanation:

From the given equation, for every 2 moles of NaClO3, 3 moles of O2 are produced.

So, for 4 moles of NaClO3:

4 moles NaClO3 / 2 moles NaClO3 = 2

Therefore, 2 * 3 moles O2 = 6 moles O2.

So, 4 moles of NaClO3 will produce 6 moles of O2.

When the grain size is reduced to 0.160 pm, the strength of mild steel is 1851 MPa.There are a number of variables that can affect mild steel's strength, including the grain size, which is controllable.

We may use the above information to determine the constants in the Hall-Petch equation: The strength of mild steel at grain size d1 = 17.43 pm is 1 = 232.9 MPa. Mild steel has a strength of 2 = 874.2 MPa when the grain size is d2 = 0.80 um (or 800 nm). This is the formula for the Hall-Petch equation: = o + Kd(-1/2). We can use the following equation to determine K: K = (σ2 - σ1)(d2^(1/2) - d1^(1/2))^(-1) (-1) When the values are plugged in, we get the following result: K = (874.2 - 232.9)(800(1/2) - 17.43(1/2))(-1) = 276.3 MPa um(1/2) We can use the following equation to determine o: σo = σ1 - Kd1^(-1/2) Plugging in the numbers yields the following result: o = 232.9 - 276.3(17.43(-1/2)) = 62.28 MPa. The Hall-Petch equation's constants are K = 276.3 MPa um(1/2) and o = 62.28 MPa. Hence, the power of the  yield strength of mild steel at 0.160 pm grain size is 1851 MPa.

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Activation energy is used to describe the energy needed for a chemical reaction to begin.

Define chemical reactions .

Breaking chemical bonds between reactant molecules (particles) and creating new bonds between atoms in product particles are two aspects of chemical reactions (molecules). While there are the same number of atoms both before and after the chemical transition, there will be a change in the number of molecules.

The least amount of energy necessary to start a process, such a chemical reaction, is known as the activation energy. Exothermic reactions require activation energy to begin, just like all other chemical reactions. Reactants require activation energy in order to move collectively, overcome repulsive forces, and begin bond breakdown.

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In A option1 is correct

What is Acid ?

In chemistry, an "acid" is a substance that donates hydrogen ions (H+) to another substance, or accepts electrons from another substance. Acids are typically characterized by a sour taste, the ability to dissolve some metals, and a pH value of less than 7 in aqueous solutions. They are often used as reagents in chemical reactions, and are important in many biological processes. Common examples of acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), and acetic acid (CH3COOH). Acids can be classified as either strong or weak, depending on the extent to which they dissociate in water, and can react with bases to form salts and water in a process called neutralization.

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The given model of metal lattice represent the metallic ions as spheres. The model is very easy to use however, the it does not represent the delocalization of electrons.

Metals have some peculiar features including malleability, ductility, luster high conductivity etc. These properties are based on the metal -metal bonds between the metallic particles in the lattice.

A metal lattice is a pool of mobile electrons and ions. They can be easily dislocated that is why metal is malleable.  The given model of metal lattice represents the metallic particles as spheres. It is easy to show how the particles can dislocate on a pressure applied.

However, it is not describing the delocalization of electrons and metal -metal bonding within the lattice. But it is enough to show the dislocation at the boundary and easiness to be flattened.

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According to the stoichiometry of the reaction for formation of water according to the given condition, 4 moles of water are 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.

In the given reaction, 32 g oxygen gives 36 g  water, thus 64 g oxygen gives 64×36/32=72 g which is equivalent to 72/18=4 moles of water.

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79942.6 calorie is the number of calories of energy absorbed by the water. The energy of an isolated system holds that energy could be transformed.

In physics, energy is indeed the quantitative quality that is imparted to a body or a physical system and is visible in the form of light and heat.

The energy of an isolated system holds that energy could be transformed in form but cannot be generated or destroyed. The joule is the International System of Units (SI) unit of measurement for energy (J).

Q = 2 kg × 4181 J / kg °C × 40°C

   = 334,480 J

   =79942.6 calorie

Therefore, 79942.6 calorie is the number of calories of energy absorbed by the water.

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Taking into account the reaction stoichiometry, the volume of H₂ required is 44.8 L.

The balanced reaction is:

2 H₂ + O₂ → 2 H₂O

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:

H₂: 2 moles

O₂: 1 mole

H₂O: 2 moles

The STP conditions refer to the standard temperature and pressure, which values are 0 °C and 1 atmosphere as a reference values for gases. In these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

To calculate the number of moles of O₂ required, you can observe the stoichiometry of the reaction. By reaction stoichiometry 2 moles of H₂O are formed by 2 moles of H₂.

Now, you can apply the following rule of three: if by definition of STP conditions 1 mole of H₂ occupies a volume of 22.4 liters, 2 moles occupies how much volume?

volume= (2 moles× 22.4 L)÷ 1 L

volume= 44.8 L

Finally, 44.8 L of H₂ are needed.

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Answer:

A

Explanation:

The Law of Conservation of Matter says that the amount of matter (mass) stays the same, even when matter changes its form.

After calculation of molar mass, The amount of grams in 1.50 moles of KMnO4 is 237.06 hence its is the Option C

The question asks to calculate the mass of 1.50 moles of KMnO4. To do this, we need to know the molar mass of KMnO4, which is calculated by adding up the atomic masses of each element in the compound, taking into account their respective number of atoms. For KMnO4, the molar mass is 39.10 + 54.94 + 4(16.00) = 158.03 g/mol.

Once we have the molar mass, we can use the formula mass = number of moles x molar mass to find the mass of 1.50 moles of KMnO4. Substituting the values, we get:

mass = 1.50 moles x 158.03 g/mol = 237.06 g

Therefore, the answer is (C) 237.06 g.

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Fan and water heater are the energy output object(s) work with the solar panel. Therefore, option B and C are correct.

Solar panels are devices that capture the sun's rays and convert them into electricity or heat. A solar panel is a collection of solar (or photovoltaic) cells that can be used to generate electricity via the photovoltaic effect.

Once you've determined the voltage and amperage, all you have to do is multiply them. The wattage of your solar panel output should be similar to the solar panel rating as a result.

Thus, option B and C are correct.

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[tex]1.223*10^3g[/tex] of   aluminum oxide (al 2o 3) will be produced when 6. 000 moles of aluminum (al ) is present.

Aluminum oxide (Al2O3) is formed when Aluminum (Al) reacts with Oxygen (O2). The equation for this reaction is:

2Al + 3O2 → Al2O3

We can thus calculate the amount of Al2O3 produced in this reaction. Since there are 6. 000 moles of Al, we can calculate the number of moles of Al2O3 produced using the equation above.

[tex]2 * 6. 000 moles Al = 12. 000 moles Al2O3[/tex]

We can then convert the moles of Al2O3 to grams using the molar mass of Al2O3, which is 101.96 g/mol.

[tex]12. 000 moles Al2O3 * 101.96 g/mol = 1.223 * 10^{3} g Al2O3[/tex]

Therefore, [tex]1.223*10^3g[/tex] of   aluminum oxide (al 2o 3) will be produced when 6. 000 moles of aluminum (al ) is present.

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The unknown concentration, c, of the acid in the remaining three-quarters of the solution is 36%.

Let x be the volume of the unknown concentration of the solution.
Then, the volume of the 20% acid solution is (40/4) = 10 ml.
We know that the total volume of the resulting solution is 40 ml, and the resulting solution is 32% acid.
This means the amount of acid in the solution is:

0.32 * 40 ml = 12.8 ml
Since we mixed 20% and c% solutions, we can set up an equation:

0.2 * 10 ml + c * x = 12.8 ml
Solving for c, we get:
c = (12.8 - 2)/x = 10.8/x

Since the volume of the unknown solution, x, is three-quarters of the total volume of the solution (40 ml),

x = 30 ml
Substituting x, we can solve for c:
c = 10.8/30 = 0.36

Therefore, the concentration of the acid in the remaining three-quarters of the solution is 36%.

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1) 1-Phenyl propan -1-ol

2) 3-methyl butanal

3) 2-Cyano ethene

4) 4 - bromo-2-methyl  pent -3- one

5) 3,5 -dihydroxy -3-enoic acid

The IUPAC nomenclature has to do with the manner that we use in chemistry to be able to name compounds. These are the rules for the naming of compounds that have been put together by the International Union of Pure and applied chemistry.

In these rules, we would have to find out the root of the compound name by counting up the number of the chains that we have and then noting the substituents that we have on the chains.

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The volume of CO2 that would form from the burning of 22 g of C3H8 at STP is 33.6 L.

Volume is described as a measure of three-dimensional space. It is often quantified numerically using SI derived units or by various imperial or US customary units.

We will calculate the number of moles of propane (C3H8) that are burned:

22 g C3H8 × 1 mole C3H8 / 44 g C3H8 = 0.5 mole C3H8

Find the number of moles of carbon dioxide (CO2) produced by the reaction:

0.5 mole C3H8 × 3 mole CO2 / 1 mole C3H8 = 1.5 mole CO2

The volume of CO2 produced at STP is found as follows:

1.5 mole CO2 × 22.4 L CO2 / 1 mole CO2 = 33.6 L CO2

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According to the problem should and charcoal particles.

Charcoal is a black, porous, and lightweight material that is produced by burning wood, wood products or other organic materials in the absence of oxygen. It is composed mainly of carbon, but also contains small amounts of hydrogen and other elements. Charcoal is an extremely versatile material that has been used for centuries for a variety of purposes, such as fuel for fires, as an abrasive for polishing and cleaning, and as a pigment for painting. Charcoal is also used in agriculture as a soil enhancer and fertilizer, and in medicine as a detoxifying agent.

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Based on the model shown, the model is limited in its depiction of the condensation of gases as it does not show how the temporary fluctuating dipoles of the molecular electron clouds result in a net force of attraction between the molecules.

The correct option is D.

Intermolecular forces are the forces that exist between the molecules of substances such as gases, liquids, and solids. The intermolecular forces in gases are negligible.

Dipole-dipole interactions, London dispersion forces (commonly referred to as van der Waals forces), and hydrogen bonds are the three main types of intermolecular interactions.

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Sometimes a neutral oxygen atoms gains electrons. The oxygen then becomes an anion with a negative charge.

All the atoms undergoes chemical reactions to attain the octet electronic configuration. It means that it tries to attain the configuration of noble gases, which has the most stable atoms.

Oxygen has 6 electrons in its outer shell. It accepts two more electrons to attain the configuration of neon. As it attains electrons the atoms become negatively charged ions, called anions. It will now become O²⁻.

So the oxygen atom attains electrons to become an anion, with negative charge.

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There are 0.0249 moles of Cu in 1.5 x 10²² atoms of Cu.

What is Mole?

A mole is a unit of measurement used in chemistry to express amounts of a chemical substance. It is defined as the amount of a substance that contains the same number of entities (such as atoms, molecules, or ions) as there are in 12 grams of pure carbon-12, which is approximately 6.022 x 10²³ entities.

This number is called Avogadro's number and is used as a conversion factor between the mass of a substance and the number of particles it contains.

To calculate the number of moles, we need to know the atomic mass of Cu, which is 63.55 g/mol.

We can use Avogadro's number, 6.022 x 10²³, to convert the number of atoms to moles:

1.5 x 10²² atoms Cu * (1 mol Cu / 6.022 x 10²³ atoms Cu) = 0.0249 mol Cu

Therefore, there are 0.0249 moles of Cu in 1.5 x 10²² atoms of Cu.

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There are 0.0249 moles of Cu in 1.5 x 10^22 atoms of Cu.

What is Mole?

A mole is a unit of measurement used in chemistry to express amounts of a chemical substance. It is defined as the amount of a substance that contains the same number of entities (such as atoms, molecules, or ions) as there are in 12 grams of pure carbon-12, which is approximately 6.022 x 10^23 entities. This number is called Avogadro's number and is used as a conversion factor between the mass of a substance and the number of particles it contains.

To calculate the number of moles, we need to know the atomic mass of Cu, which is 63.55 g/mol.

We can use Avogadro's number, 6.022 x 10^23, to convert the number of atoms to moles:

1.5 x 10^22 atoms Cu * (1 mol Cu / 6.022 x 10^23 atoms Cu) = 0.0249 mol Cu

Therefore, there are 0.0249 moles of Cu in 1.5 x 10^22 atoms of Cu.

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A student runs an experiment to figure out if the size of a wire changes how well it conducts electricity. The independent variable in this experiment is the multimeter. Therefore, option A is correct.

The amount by which an object impedes or resists an electric current is referred to as resistance. The flow of electrons is referred to as electric current. Consider an example of a person struggling to move from one shop to another in a crowded market.

Because a thin wire has fewer electrons to carry the current, its resistance is greater than that of a thick wire. The relationship between resistance and the area of a wire's cross-section is inversely proportional.

Thus, The independent variable in this experiment is the multimeter,option A is correct.

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The volume of HCl that will be formed from 3.7 liters of Cl2 would be 6.72 liters.

At STP, 22.4 liters of gas is equivalent to 1 mole of the gas.

3.7 liters of Cl2 = 3.7/22.4 = 0.17 mole

From the equation of the reaction, the mole ratio of Cl2 to HCl is 1:2. Thus, the equivalent mole of HCl that will be formed from 0.17 mole of Cl2 would be:

0.17 x 2 = 0.34 mole

0.34 mole of Cl2 = 22.4 x 0.3 = 6.72 liters

In other words, the volume of HCl that will be formed would be 6.72 liters.

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Fracture zones are areas of weakness in the oceanic crust, and they form as a result of the stress of plate tectonics. They are usually narrow and can be up to several hundred kilometers in length.

Kilometers (km) are a unit of measurement for length or distance. One kilometer is equivalent to 1000 meters and is equal to 0.6214 miles. Kilometers are commonly used to measure long distances, such as the length of a road or the distance between two cities. In science, kilometers are often used to measure the size of large objects, such as the diameter of planets, or the distance between two stars.

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Answer:

Polonium is a highly radioactive substance, meaning it emits ionizing radiation, which can cause harm to living organisms. When ingested or inhaled, polonium can damage internal organs, including the kidneys, liver, and bone marrow, and cause radiation sickness. This makes it a potent poison and an easy means to kill someone. Because of its toxic nature and the fact that it is not easily detectable, polonium has been used in assassination attempts, making it a dangerous substance to handle or be around.

Explanation:

Answer:

polonium is a highly radioactive and toxic element that can cause severs health problem if ingested or inhaled

Explanation:

The relationship between the amount of energy released by an earthquake and its magnitude is described by this formula is [tex]E = 10^{(5.24 + 1.44M)}[/tex]

Magnitude is a unit used to describe something's size or power. It is a technique for expressing the size of an object, event, or phenomena as a number. For instance, the Richter scale is typically used to indicate the magnitude of earthquakes. Magnitude can also be used to describe a sound, force, or amount's strength or intensity. For instance, the intensity of a sound is typically measured in decibels, and the intensity of a force is typically measured in newtons. Magnitude can also be used to denote a number's size.

For a magnitude 5 earthquake, [tex]E = 10^{(5.24 + 1.44 \times 5)} = 10^{(10.24)} = 8.02 \times 10^9[/tex] joules of energy.

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Answer:

168.64 grams of O2

Explanation:

To burn 46.8 grams of propane (C3H8), we need to find the amount of oxygen that reacts with it according to the balanced chemical equation:

C3H8 + 5O2 -> 3CO2 + 4H2O

From the equation, 1 mole of propane (C3H8) reacts with 5 moles of oxygen to form 3 moles of carbon dioxide and 4 moles of water. The number of moles of propane can be calculated as follows:

46.8 g C3H8 / (44.1 g/mol) = 1.054 mol C3H8

Therefore, 1.054 mol of propane (C3H8) requires 5 x 1.054 = 5.27 moles of oxygen to burn completely. To find the mass of the oxygen in grams, we multiply the number of moles by the molar mass of oxygen (O2):

5.27 moles O2 * 32.0 g/mol = 168.64 g O2.

So, 168.64 grams of oxygen are required to burn 46.8 grams of propane (C3H8).

Answer:

142 can be expressed in scientific notation as 1.42 x 10².

Explanation: