At what temperature is more KCl able to dissolve: 40°C or 90°C?


(You don't have to give out a paragraph, but also explain why, so that I may understand)

Answer:

F and Cu.

Explanation:

Hello,

In this case, by knowing that the farther the elements in the periodic table, the more ionic they are, in addition to the difference in the electronegativity which must be greater than 1.7 for the bond to be ionic, we can substantiate that the iron and the copper don't exhibit an ionic bond as shown below:

[tex]\Delta E=E_{Cu}-E_{Fe}=1.9-1.83=0.07[/tex]

Such value is characteristic for covalent bonds.

Best regards.

Answer is: L.

The process by which a solid changes directly to a gas without first becoming a liquid is called sublimation.

Sublimation is an endothermic process.

For example dry ice (carbon(IV) oxide in solid state) is used because of sublimation in nightclubs, fog machines, at theaters, haunted house attractions .

1) Gas: does not have a definite shape or volume and changes to liquid on cooling.

2) Liquid: has definite volume but not shape and changes to solid on cooling.

3) Solid: has definite shape and volume and changes to liquid on heating.

Hello,

The correct answer is B) Molecules

Hope this helps!!!! :)

(Took the Science test)

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Molecules come just after atoms in the organization chart of living things. Therefore, option B is correct.

A molecule can be defined as a combination or arrangement of two or more atoms that create the smallest unit into which the structure and chemical properties can be classified and preserved by a pure substance.

A molecule can be homonuclear if it exhibits atoms of a single chemical element such as hydrogen molecule (H₂) or it can be heteronuclear such as water (H₂O).

A molecule exhibits an arrangement of atoms held by the forces of valence. Two atoms of the same element that are chemically combined comprise diatomic molecules.

Heteronuclear diatomic molecules have two combined atoms of different elements such as hydrochloric acid (HCl), Carbon monoxide (CO), etc.

The molecules in living organisms are biomolecules such as carbohydrates, lipids, nucleic acids, proteins,

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Determine which chemicals to use to fight different types of fires.

The element that has been broken down and released particles and energy is said to be radioactive in nature. The radioactive isotopes undergo nuclear fission to produce lighter isotopes and evolve energy.

Heavy unstable radioactive isotopes undergo nuclear decay to by the emission of charged particles alpha or beta and form lighter elements with more half life with the evolution of energy.

This break down  of an atomic nuclei  into lighter elements with the releases of massive energy is called nuclear fission. Almost all elements have two or more isotopes. But not all of them are stable and some are radioactive.

This radioactive elements are undergoing nuclear fission by the emission of alpha or beta particles. For example, uranium, plutonium, carbon -14 etc are radioactive elements.

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Answer:

C15H8Cl8O2

Explanation:

C15H8Cl8O2

The strongest base in the system is the cyanide ion.

The following steps must be followed here;

The calculation of the pH of the solution, the strongest base in the system are shown in the file attached. The pH is the negative logarithm of the hydrogen ion concentration of the solution as shown.

Hence, the strongest base in the system is the cyanide ion.

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Final answer:

The molar mass of a gas can be calculated using the ideal gas law equation at STP. The molar mass of the gas with a density of 1.97 g/L at STP is 44.1 g/mol.

Explanation:

The molar mass of a gas can be calculated using the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. At STP (Standard Temperature and Pressure), the pressure is 1 atm and the temperature is 273 K. We can rearrange the equation to solve for the molar mass, M:

M = (PV) / (nRT)

Given that the density of the gas is 1.97 g/L at STP, we can calculate its molar mass by converting the density to grams per mole:

Density = Molar mass / Molar volume

Molar volume at STP = 22.4 L/mol

Thus, Molar mass = Density * Molar volume

Molar mass = 1.97 g/L * 22.4 L/mol = 44.1 g/mol

The molar mass of the gas is 44.1 g/mol.

Final answer:

The ratio of densities (ρ1/ρ2) of two non-mixing liquids in a U-tube that are in equilibrium can be found by equating the hydrostatic pressures of the liquids at the same height, resulting in the ratio ρ1/ρ2 = h2/h1.

Explanation:

The student is inquiring about the ratio of densities (ρ1/ρ2) of two non-mixing liquids in a U-tube that are in equilibrium. To find this ratio, we use the fact that the pressure at the same height must be the same in both arms of the U-tube if they are in the same liquid. Considering the point at the interface on the side with Liquid 1 and a point at the same level in the arm with Liquid 2, we can write the pressure due to Liquid 1 as P1 plus the atmospheric pressure. Likewise, the pressure due to Liquid 2 is P2 plus the atmospheric pressure. Because these pressures must be equal, we can set up the equation P1 + atmospheric pressure = P2 + atmospheric pressure.

Now, if we consider the column of Liquid 1 to have a height of h1 and the column of Liquid 2 to have a height of h2, we can equate the hydrostatic pressures using ρ1gh1 for Liquid 1 and ρ2gh2 for Liquid 2. The resulting equation is ρ1gh1 = ρ2gh2, where g is the acceleration due to gravity. Canceling out the common factor of g, we have ρ1h1 = ρ2h2. Dividing both sides by h2 and ρ1, we get the ratio of densities as ρ1/ρ2 = h2/h1.

Final answer:

Option C) CO2

Explanation:

All the substances listed are nonpolar, meaning they mainly experience London dispersion forces, which are the weakest intermolecular forces. However, they can vary in strength based on molecular mass and shape. Among the options, CO2 has more polarizable electrons due to its larger size and linear shape compared to Xe, H2, and CH4, thus exhibiting slightly stronger London dispersion forces. However, it's crucial to note that this comparison is subtle because the strengths of dispersion forces can be closely contested among molecules of similar sizes and molar masses. Therefore, CO2 would exhibit the strongest intermolecular forces among the given choices, but the difference might not be highly significant compared to the others, especially CH4.

Answer:

D

Explanation:

I took the test

Answer:

b

Explanation:

b. subsection is the correct answer.

hopes this helps

The correct answer is option C, that is, the electric potential (volts) divided by the current (amperes) equals the resistance (ohms).  

According to the Ohm's law, the current via a conductor between the two points is directly equivalent to the voltage through the two points. With the introduction of resistance, that is, the constant of proportionality, the mathematical equation, which describes the association is:  

I = V/R

Here, I is the current via the conductor in the units of amperes, R is the resistance of the conductor in the units of ohms, and V is the voltage determined across the conductor in the units of volts.  

Final answer:

The key chemical property of amines is their basicity, related to the unshared electron pair on the nitrogen atom. Amines are protonated to form ammonium cations and react similarly to ammonia. Amines vary in their physical properties based on the degree of nitrogen substitution.

Explanation:

The most important chemical property of amines is their basic nature. Amines are readily protonated to form ammonium cations, which is a direct consequence of the presence of an unshared electron pair on the nitrogen atom, making them Lewis bases. In their role as bases, amines can accept protons (H+), and thus, when an amine reacts with an acid, an ammonium salt is typically formed. It's also worth noting that the basic strength of amines makes them react similarly to ammonia since both have a lone pair on the nitrogen atom that facilitates this basic nature.

Amines are categorized as primary, secondary, and tertiary, depending on the number of hydrocarbon groups bonded to the nitrogen atom. In the case of a quaternary ammonium ion, the nitrogen has four bonds to carbon, which is rarer in biomolecules. Lastly, the physical properties of amines, such as volatility and solubility, are influenced by the extent of substitution on the nitrogen atom.

The rate of appearance of Br2 in the gas phase reaction 2HBr(g) → H2(g) + Br2(g) when the rate of disappearance of HBr is 0.190 M/s at 150 °C is 0.095 M/s.

To determine the rate of appearance of Br2 in the reaction 2HBr(g) → H2(g) + Br2(g), we use the stoichiometry of the reaction. Given that the rate of disappearance of HBr is 0.190 M/s, and considering that 2 moles of HBr produce 1 mole of Br2, the rate of appearance of Br2 would be half of the rate of HBr's disappearance.

Therefore, the rate of appearance of Br2 is:

So, the rate of appearance of Br2 is 0.095 M/s.

Final answer:

approximately 8.51 kg of the ore must be processed

Explanation:

To calculate the minimum mass of ore required to obtain 1.00 kg of phosphorus from an ore containing 58.9% calcium phosphate (Ca3(PO4)2), we follow these steps:

First, calculate the molar mass of calcium phosphate, Ca3(PO4)2. The molar mass is (3×40.08 for Ca) + (2×30.97 for P) + (8×16 for O) = 310.18 g/mol.

Next, understand that calcium phosphate contains two moles of phosphorus per formula unit, which means every mole of calcium phosphate yields 2 moles of phosphorus.

To get 1.00 kg (or 1000 g) of phosphorus, we need 1000 g / 30.97 g/mol = 32.29 moles of phosphorus.

Since 1 mole of Ca3(PO4)2 yields 2 moles of phosphorus, we need 32.29 / 2 = 16.145 moles of calcium phosphate.

To find the mass of calcium phosphate required, multiply the moles by its molar mass: 16.145 mol × 310.18 g/mol = 5006.05 g.

Given that the ore is 58.9% calcium phosphate, the total mass of the ore needed is calculated as 5006.05 g / 0.589 = 8505.18 g, or approximately 8.51 kg.

During the Glacial erosion by abrasion the glaciers are loaded with other rock fragments as a tool for erosion of the bedrock. These rock fragments are dragged on the bedrock during the forward movement of the glacier and causes the rocks that comes in contact to abrade and the process is known as abrasion.

These abraded mass can also get trapped in the glacier as sub glacial, intra glacial and even super glacial deposit , causing the glacier to increase in mass and hence may flow easily where the glacier flow because of gravity. Abrasion also causes melting of snow because of the frictional heat produced during interaction of rock fragments and country rock.

option D

Answer:

The answer is D

Explanation:

plucks up rocks and incorporates them into its ice.

The transition metals are located in the d block of the periodic table, which is found between Groups 3-12 and includes elements with partially filled d orbitals.

The transition metals are located in the d block of the periodic table. These elements, which have partially filled d orbitals, are found between Groups 3-12. The d block is characterized as the middle 10 columns of the periodic table. While the s block consists of the first two columns on the left side of the periodic table, and the p block refers to the right-most six columns, the d block is distinct in that it includes the transition metals known for their unique chemical and physical properties such as conductivity and malleability. The f block, often considered separate, is comprised of the lanthanides and actinides and does not include the transition metals.

Answer:

I, V, VI

Explanation:

During a state change, e.g solid state to liquid state, energy (absorbed or released) is used to break the bonds between the molecules. In the case of boiling,melting, and sublimation energy is absorbed to break the molecule bonds.

The element with a molar mass of 30.974 g/mol is phosphorus. Molar mass corresponds to the mass of one mole of a substance, which contains Avogadro's number of particles.

The element with a molar mass of 30.974 g/mol is phosphorus (P). The concept of molar mass is significant in chemistry, as it relates the mass of the substance to the number of molecules or atoms. One mole of a substance corresponds to 6.022 × 10²³ particles (Avogadro's number), whether they're molecules, formula units, or atoms. The molar mass in grams per mole (g/mol) is numerically equal to the average atomic mass of the element.

In this case, a quick examination of the periodic table will reveal that phosphorus has an atomic mass very close to 30.974 amu, which corresponds to its molar mass in grams. Hence, 1 mole of phosphorus atoms has a mass of 30.974 g and contains 6.022 × 10²³ atoms of phosphorus.

Answer:

False is your answer