a compound containing chromium and silicon contains 73.52 mass percent chromium. determine its empirical formula.

Molarity

Chemists primarily need the concentration of solutions to be expressed in a way that accounts for the number of particles that react according to a particular chemical equation. Since percentage measurements are based on either mass or volume, they are generally not useful for chemical reactions. A concentration unit based on moles is preferable. The molarity (M) of a solution is the number of moles of solute dissolved in one liter of solution. To calculate the molarity of a solution, you divide the moles of solute by the volume of the solution expressed in liters.

Note that the volume is in liters of solution and not liters of solvent. When a molarity is reported, the unit is the symbol M and is read as “molar”. For example a solution labeled as 1.5 M NH 3 is read as “1.5 molar ammonia solution”.

Sample Problem: Calculating Molarity

A solution is prepared by dissolving 42.23 g of NH 4 Cl into enough water to make 500.0 mL of solution. Calculate its molarity.

Step 1: List the known quantities and plan the problem.

& underline{text{Known}} &&underline{text{Unknown}} \& text{mass}=42.23 text{g} NH_4Cl && text{molarity}= ? text{ M}\& text{molar mass} NH_4Cl=53.50 text{g} / text{mol} \& text{volume solution}=500.0 text{mL}=0.5000 text{L}

The mass of the ammonium chloride is first converted to moles. Then the molarity is calculated by dividing by liters. Note the given volume has been converted to liters.

Step 2: Solve.

42.23 text{ g } NH_4Cl times frac{1 text{ mol } NH_4Cl}{53.50 text{ g } NH_4Cl} &= 0.7893 text{ mol } NH_4Cl\frac{0.7893 text{ mol } NH_4Cl}{0.5000 text{ L}} &= 1.579 text{ M}

Step 3: Think about your result.

The molarity is 1.579 M, meaning that a liter of the solution would contain 1.579 mol NH 4 Cl. Four significant figures are appropriate.

In a laboratory situation, a chemist must frequently prepare a given volume of solutions of a known molarity. The task is to calculate the mass of the solute that is necessary. The molarity equation can be rearranged to solve for moles, which can then be converted to grams. See sample problem 16.3.

Sample Problem:

A chemist needs to prepare 3.00 L of a 0.250 M solution of potassium permanganate (KMnO 4 ). What mass of KMnO 4 does she need to make the solution?

Step 1: List the known quantities and plan the problem.

Known

molarity = 0.250 M

volume = 3.00 L

molar mass KMnO 4 = 158.04 g/mol

Unknown

mass KMnO 4 = ? g

Moles of solute is calculated by multiplying molarity by liters. Then, moles is converted to grams.

Step 2: Solve.

text{mol KMnO}_4 = 0.250 text{ M KMnO}_4 times 3.00 text{ L} &= 0.750 text{ mol KMnO}_4\0.750 text{ mol KMnO}_4 times frac{158.04 text{ g KMnO}_4}{1 text{ mol KMnO}_4} &=119 text{ g KMnO}_4

Step 3: Think about your result.

When 119 g of potassium permanganate is dissolved into water to make 3.00 L of solution, the molarity is 0.250 M.

The cheetah chasing its prey has more kinetic energy than an elephant walking slowly across a field, as the kinetic energy of the cheetah is significantly higher than that of the elephant.

Kinetic energy formula is K.E. = 1/2mv² where m is the mass of the object and v is the velocity or speed of the object. Therefore, an elephant walking slowly across a field could have more kinetic energy than a cheetah chasing its prey.

If K = 3, C = 1

For the elephant:Mass, m = 5000 kg (150*33.33)

Velocity, v = 1 m/s

Kinetic energy, K.E. = 1/2mv² = 1/2 * 5000 * 1² = 2500 J

For the cheetah:Mass, m = 50 kgVelocity, v = 20 m/s

Kinetic energy, K.E. = 1/2mv² = 1/2 * 50 * 20² = 10000 J

Therefore, the cheetah chasing its prey has more kinetic energy than an elephant walking slowly across a field, as the kinetic energy of the cheetah is significantly higher than that of the elephant.

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Answer:

Digestion is a chemical change.

Explanation:

The Digestion part of the digestive cycle is a chemical change, as the smaller particles are mixed in with the enzymes and become simple molecules. This is NOT reversible. The chewing and breaking food into smaller pieces is a chemical change as well, as the smaller pieces of the food get mixed with each other and saliva, forming a mushy, pulpy substance. This is also irreversible. Thus, a chemical change. (I think)

Answer:

b. a meadow replacing a pond in it's flood plain

Explanation:

I'ts a secondary succession.

The brass is getting hotter as a result of energy passing from the water to it. Instead of making the brass colder, the water is transferring energy to the brass, which lowers its temperature.

The water is transferring energy to the brass, which causes the brass to gain heat while losing heat from the water, making the water hotter while the brass becomes colder.

The metal will eventually cool while the water warms up. The temperatures of the two things will eventually be equal. When this occurs, it is said that they are in thermal equilibrium with one another. The hot metal is transferring energy to the water in the interim.

Heat is transferred by a fluid, such as water or air, by convection. As the fluid (liquid or gas) flows from one place to another, it also transfers heat. A current is a term used to describe the movement of heated water or air. Heat is transferred by electromagnetic waves or radiation.

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Matter generally exists in three different physical states, namely solid, liquid and gaseous state. The plasma is defined as the fourth state of matter.

The matter is composed of very minute particles which cannot be seen with our eyes. It can be classified into different categories on the basis of the state in which they exist. These are called states of matter.

In solids, particles are tightly packed and they have a fixed volume and shape. In liquids, particles are less tightly packed as compared to solids and they take the shape of the vessel in which they are kept.

In gases, particles can move freely and they do not have a fixed volume nor a shape. A plasma is an electrically charged gas and they also do not have a fixed volume nor a shape.

Thus, solid, liquid, gas and plasma are states of matter.

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The number of molecules in 10.0 gram of NaOH is 15 * 10²².

To solve this question, we need to understand some terms of mole concept,

Mole - It is the amount of substance containing same number of molecules or atoms as there are atoms in 12 gram of carbon-12 isotope.

Molecules - It is group of atoms bonded together, representing the smallest fundamental unit of a chemical compound taking part in chemical reaction.

Molecular weight - The sum of atomic masses of all atoms in molecules.

Avogadro number - It is the number of atoms, ions, electrons, molecules in one mole of substance. It is represented as NA.

NA = 6.0 * 10²³ (approx)

To calculate the number of molecules, we apply the formulae,

no. of molecules = moles * NA

moles = weight / molecular weight

moles = 10.0 / 40

          = 0.25

Substituting this value to calculate number of molecules,

no. of molecules = 0.25 * 6.0 * 10²³

                            = 15 * 10²²

Therefore the number of molecules of in 10.0 g of NaOH is 15 * 10²².

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Answer:

Sunlight penetrates the top layers of the ocean, so photosynthesis occurs there.

Explanation:

Please give brainlist if you find it helpful

Gibbs free energy (G°) is a thermodynamic quantity that can be used to predict the spontaneity of a reaction. It is defined as G° = -RTlnK, where R is the gas constant, T is the temperature in kelvins, and K is the equilibrium constant.

For part (a) of your question, at 25°C (which is equivalent to 298.15 K), the value of G° for the autoionization of water can be calculated as follows:

G° = -RTlnKw

= -(8.314 J/mol·K)(298.15 K)ln(1.00×10^-14)

= 79.9 kJ/mol

For part (b) of your question, at 40°C (which is equivalent to 313.15 K), the value of G° for the autoionization of water can be calculated as follows:

G° = -RTlnKw

= -(8.314 J/mol·K)(313.15 K)ln(2.92×10^-14)

= 83.6 kJ/mol

(a) Autoionization of Water:In the autoionization of water, two water molecules react to produce a hydroxide ion (OH-) and a hydronium ion (H3O+), as shown:H2O(l) + H2O(l) ⇌ H3O+(aq) + OH-(aq)At 25°C, the equilibrium constant Kw is 1.0 × 10-14. Therefore, the standard Gibbs free energy change for the autoionization of water at 25°C is 74.2 kJ/mol.

Gibbs free energy change for the reaction can be calculated using the following equation:ΔG° = - RT ln KwWhere, ΔG° = standard Gibbs free energy changeR = universal gas constant = 8.314 J K-1 mol-1T = temperature in KelvinKw = ion-product constant = [H+][OH-] = 1.0 × 10-14Thus,ΔG° = - (8.314 J K-1 mol-1) × (298 K) × ln (1.0 × 10-14) = 74.2 kJ/molTherefore, the standard Gibbs free energy change for the autoionization of water at 25°C is 74.2 kJ/mol.

(b) At 40°C, the ion-product constant Kw is 2.9 × 10-14.ΔG° at 40°C can be calculated using the same formula. Thus,ΔG° = - (8.314 J K-1 mol-1) × (313 K) × ln (2.9 × 10-14) = 72.6 kJ/molTherefore, the standard Gibbs free energy change for the autoionization of water at 40°C is 72.6 kJ/mol.

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Answer:

2mg+2hcl------>mgcl2+h2

Answer: When magnesium reacts with hydrochloric acid, it produces magnesium chloride and hydrogen gas. To write the formula for this reaction, we first need to identify the elements involved and their respective chemical symbols. The chemical symbol for magnesium is Mg, the symbol for hydrochloric acid is HCl, and the symbol for hydrogen is H.

Next, we need to balance the equation by making sure that the number of atoms of each element is the same on both sides of the arrow. In this case, we have one atom of magnesium on the left side of the arrow and one atom of hydrogen on the right side. However, we also have one atom of chlorine on the left side and two atoms of hydrogen on the right side. To balance the equation, we need to add a coefficient of 2 in front of the HCl on the left side, so that the equation becomes:

Mg + 2 HCl -> MgCl2 + H2

This balanced equation shows that for every one atom of magnesium that reacts with two atoms of hydrochloric acid, two atoms of magnesium chloride and two atoms of hydrogen gas are produced.

Answer: How The World Works

Explanation: Our world is made out of atoms, molecules and ions. Their behavior determines the properties of the substances we encounter in our daily lives: their structure, color, smell, and the way they interact with each other.

Answer:

Molar mass Na2CO3 = 2*23 + 12 + 3*16 = 106 g/ mol

Mass of 1 mol Na2CO3 = 106 g

mass (Na2CO3) = 106g*250cm³/1000cm³ = 26.5 g

1) It is necessary because all Na2CO3 will be in the solution, and no Na2CO3 would be lost.

2) Because the solution that was formed after rinsing beaker contains Na2CO3.

3) Eyes should be on the level of calibration mark of the volumetric flask.

4) It is necessary to prevent evaporation of water, and changing , because of it, the concentration of the solution.

Answer:

Intensive

Explanation:

The electrical conductivity of a wire depends on its composition, not the length of the wire.

Hope this helps! If correct pls mark brainliest :)

As copper wire was very thin, it will have great electrical conductance and copper wire has a intensive property.

         The electrical resistance of a wire is given by

                                R = ρl/A.

where,

R -Resistivity of the material,

l - length of the wire,

A - cross-sectional area of the wire

As we know the formula, it can be explained as:

Hence, we came to know that, thin wires have a greater electrical resistance than a  thick wire.

So, copper wire was very thin and it can conduct electricity.

Here, concluded that copper wire was very thin and it has intensive property.

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The impact of e-commerce on commercial real estate is significant. E-commerce sales have grown steadily, accounting for a considerable portion of overall sales.

The growth of e-commerce has fueled the demand for distribution spaces, specifically distribution centers and warehouses, which play a crucial role in the supply chain and logistics of packaging and shipping goods to customers. These spaces are sought after by e-commerce giants, who prefer locations near large cities while still providing ample room for large buildings. Suburban areas, such as Katy, Brookshire, and Waller near Houston, are experiencing significant growth in the establishment of distribution centers.

On the other hand, the rise of online shopping has posed challenges for brick-and-mortar retailers. Many physical retail spaces have struggled to remain open or have had to downsize. As a result, there is a trend towards smaller retail spaces, which require less inventory in-store. This trend encourages a combination of online and in-store shopping, known as hybrid shopping. The Covid-19 pandemic further accelerated this trend as consumers sought the convenience and safety of online shopping with options like curbside or in-store pick-up. Even as restrictions ease, this approach is expected to remain popular.

To adapt to the changing retail landscape, integrating technology into physical retail spaces has become crucial. Technology tools, such as mobile apps, can enhance the shopping experience, offer special promotions, and provide valuable data on customer behavior. Retailers, especially large lifestyle shopping centers, have been proactive in blending technology with consumer experiences to stay relevant and attract customers.

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The volume in L of a balloon filled with 0.200 moles of helium at 1.00 ATM at 0.00°C is 48.90 L

What is ideal gas equation?
The equation of state for a fictitious ideal gas is known as the ideal gas law, also known as the ideal gas equation. Although it has some restrictions, it is a fair estimate of the behaviour of many gases under various circumstances. Benoît Paul Émile Clapeyron introduced it for the first time in 1834 as a synthesis of a empirical Boyle's law, Charles' law, Avogadro's law, and Gay-law. Lussac's An amount of gas's pressure, volume, as well as temperature all affect its state. These are simply related in two ways by the equation as it is used today. The kelvin is the proper SI unit to use when expressing the temperature in the equation of state because it is an absolute temperature.

ideal gas equation

PV = nRT

v = nRT/P

V= 0.2 x 0.08206 x 298 / 1

V = 48.90

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Answer:

636.86 K

Explanation:

From the question given above, the following data were obtained:

Initial temperature (T1) = 333 K

Initial pressure (P1) = 4 atm

Final pressure (P2) = 7.65 atm

Final temperature (T2) =?

NOTE: The volume is constant.

Since the volume is constant, we can obtain the new temperature the gas by using the following formula as illustrated below:

P1 /T1 = P2 /T2

4/333 = 7.65/T2

Cross multiply

4 × T2 = 333 × 7.65

4 × T2 = 2547.45

Divide both side by 4

T2 = 2547.45 / 4

T2 = 636.86 K

Therefore, the new temperature of the gas is 636.86 K

Answer:

It's 637 <3

Explanation:

Round 636.86 to get 637, proven on CK12

Answer:

Atom

Explanation:

An atom is the smallest unit which represents the an element.

It retains the chemical properties of an element.

Answer: 1, magnesium & mg

2, two energy shells

Explanation:

Answer:

Soil is often derived from rock

Explanation:

Respuesta:

Los modelo atómicos han permitido representar el modo de funcionamiento de los átomos. A lo largo de la historia han surgido un numero de modelos atómicos diferentes incluyendo los modelos de Bohr, Thomson, Rutherford, Sommerfeld, Dalton y Schrödinger.

Explicación:

El modelo atómico propuesto por John Dalton (1808) demostró que las sustancias químicas reaccionan en proporciones fijas y cómo mediante su combinación se producen elementos diferentes. Dalton fue el primero en postular la existencia de elementos indivisibles llamados átomos. A continuación, Thomson (1904) desarrolló un modelo en el cual el átomo estaba compuesto por protones con carga positiva y electrones con carga negativa los cuales se incrustaban uniformemente dentro de este átomo, asemejándose a las pasas de uva de un budín. En 1911, Ernest Rutherford desarrolló un nuevo modelo donde la masa principal del átomo tenía carga positiva y se localizaban en el núcleo, mientras que los electrones con carga negativa se posicionaban en la región externa del átomo. Subsecuentemente, Niels Bohr (1913) represento el funcionamiento del átomo de hidrógeno mediante un protón inmóvil en el núcleo atómico y un electrón girando a su alrededor. El modelo atómico de Sommerfeld permitió generalizar el diagrama de Bohr a otros tipos de átomos mas allá del Hidrógeno, incluyendo diferentes niveles energéticos para cada átomo particular. El modelo de Schrödinger​ (1926) permitió corregir aquellas discordancias surgidas del modelo atómico de Bohr. Schrödinger incluyó diferentes niveles y subniveles de energía a los electrones e incorporó órbitas elípticas a su movimiento, con lo cual permitiendo predecir los efectos relativos de los campos magnético y eléctrico sobre el movimiento de los electrones.

One H2SO4 molecule has a 98 Atomic Weight Unit atomic mass. H2SO4 has an atomic mass of 98 grams per mole. One mole of H2SO4 is therefore present in 98 grams of H2SO4.

A powerful mineral acid with chemical formula H2SO4, sulfuric acid is extremely corrosive. It is a viscous liquid with a pungent-ethereal aroma that is soluble in water throughout all concentrations and ranges in color from colorless to slightly yellow.

An extremely potent acid is sulfuric acid (H2SO4). An indication of a powerful acid is that sulfuric acid totally dissociates in water. Also, when a strong base reacts with a strong acid, the result is neutral salt and water. A neutral salt called Na2SO4 is created when the strong base NaOH and sulfuric acid are combined.

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Okay, let's solve this step-by-step without using quadratics:

1) The equilibrium constant Kc = 0.36 means the equilibrium lies to the left. So there will be more N2O4 than NO2 at equilibrium.

2) The initial concentration of N2O4 is 0.1 mol dm^-3. Let's call this [N2O4]initial.

3) At equilibrium, the concentrations of N2O4 and NO2 will be [N2O4]equil and [NO2]equil respectively.

4) We know the equilibrium constant expression for this reaction is:

Kc = ([NO2]equil)^2 / [N2O4]equil

5) Setting this equal to 0.36 and plugging in 0.1 for [N2O4]initial, we get:

0.36 = ([NO2]equil)^2 / (0.1 - [NO2]equil)

6) Simplifying, we get:

0.036 = [NO2]equil^2

7) Taking the square root of both sides, we get:

[NO2]equil = 0.06 mol dm^-3

So the equilibrium concentration of NO2 is 0.06 mol dm^-3.

Let me know if you have any other questions! I can also provide a more step-by-step explanation if needed.

Answer:

We smell hot food from distance because of the diffusion process. Diffusion is the spreading out and intermixing of particles From one substance into another substance due to the movement of particles.

Explanation:

The amount of energy released would be 1917.96 kJ.

We can start by calculating the number of moles of methane used up in the reaction:

Number of moles = mass / molar mass

molar mass of CH4 = 12.01 + 4(1.01) = 16.05 g/mol

Number of moles = 38.0 g / 16.05 g/mol = 2.37 mol (rounded to two decimal places)

Next, we can calculate the total energy released by the combustion of this amount of methane:

Energy released = energy released per mole x number of moles

Energy released = 808 kJ/mol x 2.37 mol = 1917.96 kJ (rounded to two decimal places)

Therefore, if you used up 38.0 g (or 2.37 mol) of methane in 5 minutes, you would have released approximately 1917.96 kJ of energy.

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The correct ranking of these states of matter from slowest to fastest particle speed is solid, liquid, gas. Option C.

In a solid, the particles are tightly packed and have the lowest amount of kinetic energy. They vibrate in place, and their movement is restricted.

In a liquid, the particles have more kinetic energy than in a solid, and they can move more freely. They can slide past each other, but they are still close together.

In a gas, the particles have the highest amount of kinetic energy and move very quickly in random directions. They are far apart from each other and have very little interaction.

Therefore, the ranking from slowest to fastest particle speed is solid, liquid, and gas.

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Answer:

See the explanation

Explanation:

In this question we have to take into account that we have to get the same amount of atoms on both sides, so:

Reaction 1

\(BaCl_2~+~H_2SO_4~=>~BaSO_4~+~2HCl\)

We have 1 Ba, 2 Cl, 2 H and 4 O on both sides

Reaction 2

\(Ca(OH)_2~+~CO_2~=>~CaCO_3~+~H_2O\)

We have 1 Ca, 2O, 2 H and 1 C on both sides

Reaction 3

\(2Al~+~3CuCl_2~=>~2 AlCl_3~+~3Cu\)

We have 2 Al, 3 Cu, and 3 Cl on both sides

Reaction 4

\(2SO_2~+~O_2~=>~2SO_3\)

We have 2 A and 6O on both sides

Reaction 5

\(2NH_3~+~3CuO~=>~3Cu~+~N_2~+~3H_2O\)

We have 2 N, 3 H, 3 Cu and 3O on both sides.

I hope it helps

Answer:

7 covalent bonds

Explanation:

Answer:

In these compounds carbon, nitrogen, oxygen, and chlorine atoms have four, three, two, and one bonds, respectively.

Explanation:

The correct statement about the buddy system for allocating memory is:

C. With the buddy system, memory segments can be either divided or coalesced to satisfy an allocation request.

The buddy system is a memory allocation technique used in operating systems. It divides memory into fixed-size blocks or segments, typically in powers of two. When a memory allocation request is made, the system looks for a free block of suitable size. If the block is larger than required, it can be divided or split into smaller blocks to satisfy the request. Conversely, if adjacent blocks are free, they can be coalesced or merged to form a larger block for allocation.

A. The buddy system is not specifically designed for quickly allocating pages on demand for user-space applications. It is a general memory allocation strategy used in various contexts.

B. The buddy system may still result in internal fragmentation. Internal fragmentation occurs when allocated memory blocks are slightly larger than the requested size, leaving unused space within the block.

D. The buddy system does not guarantee physically contiguous memory allocation. It can allocate memory from different available blocks, which may or may not be physically contiguous.

Therefore, the only true statement is C. With the buddy system, memory segments can be either divided or coalesced to satisfy an allocation request.

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