Calculate the specific heat in J/(g·ºC) of an unknown substance if a 2. 50-g sample releases 12. 0 cal as its temperature changes from 25. 0ºC to 20. 0ºC. ________J/(g·°C)

Answer:

astronomers know that sunspots are associated with magnetic fields because they can look at the spectral lines that come from the sunspots and measure by how much these lines are split.

Answer:  There are many properties of a metal which is taken into consideration when it is used for construction

Explanation:

The properties can be physical, chemical, et cetera. The physical properties that is considered are:

1. Durability:  It can be defined as the property of the material to withstand the atmospheric pressure and other factors.

2. Density: The ratio of mass by volume of a material (homogeneous material) is called as density.

3. Fire resistance: The ability of the material to withstand in fire without changing its size or shape.

4. Weather resistance: The ability of the material to withstand the weather which could be variable round the year.

5.Water absorption: The ability of the material to absorb water and retain it.

Fuel consumption and other atoms than carbon and hydrogen, such as sulfur, nitrogen, or oxygen, have a direct impact on carbon dioxide emissions.

Charcoal, a solid, and oxygen, a gas, are the reactants in the described reaction, and carbon dioxide gas is the result. It is possible to write the chemical equation as C (s) + O2 (g) CO2 (g) Q.

Since heat is produced during the reaction, it is an exothermic reaction. As carbon and oxygen combine to generate carbon dioxide, it is a combination reaction. It is a combustion reaction because oxygen causes carbon to burn.

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About a century ago, in 1911, Rutherford discovered the atomic nucleus, then in 1919, he witnessed the proton.

For a long time, people believed that Atom was the final particle and the building block of every other component in the universe. However, in the year 1911, Rutherford's atomic model depicting the presence of nucleus shattered the argument that atom is the ultimate unbreakable particle.

Rutherford's experiment also approved that there must be more than just protons in the nucleus. For example, it was previously known that helium had an atomic number of 2, but a mass number of 4.

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Intermolecular forces that contribute to creating a solution of CH2Cl2 in H2O are London Dispersion forces, Dipole-dipole interactions, and Hydrogen bonding.

London Dispersion forces occur between all molecules and result from the fluctuating distribution of electrons in the molecules, leading to a temporary dipole moment.

Dipole-dipole forces are attractive interactions between the positively charged end of one molecule and the negatively charged end of another molecule.

Hydrogen bonding occurs between molecules with hydrogen atoms covalently bonded to highly electronegative elements such as nitrogen, oxygen, or fluorine. In the case of CH2Cl2 in H2O, hydrogen bonding could occur between the polar H2O molecules and the chlorine atoms of the CH2Cl2 molecule.

Therefore, Intermolecular forces that contribute to creating a solution of CH2Cl2 in H2O are London Dispersion forces, Dipole-dipole interactions, and Hydrogen bonding.

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(a) Using the ideal gas law, the pressure in the flask is approximately 11.43 atm.

(b) Using the van der Waals equation, the pressure in the flask is approximately 9.44 atm.

(c) There is a difference between the pressures because the van der Waals equation accounts for the volume of the molecules and the attractive and repulsive forces between them.

(d) The correction for the volume of the molecules is more significant than the correction for the attractive forces between molecules because the volume correction is proportional to the amount of gas. Since the amount of gas is relatively small compared to the square of the amount of gas, the correction for the volume of the molecules is more significant.

a) The ideal gas law is PV = nRT. Here, P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature.

Using the ideal gas law:

PV = nRTP = (nRT)/V

Where,

P = Pressure of CO₂

n = Number of moles of CO₂

V = Volume of CO₂

T = Temperature of CO₂

R = Gas constant = 0.08206 L-atm/mol-K (This value can be converted to other units based on the unit of pressure, volume, and temperature used in the problem)

Substitute the values into the formula:

P = (0.467 mol * 0.08206 L-atm/mol-K * (159°C + 273.15)) / 0.245 L

P = 11.43 atm (approximately)

b) The van der Waals equation is given as (P + an²/V²)(V - nb) = nRT, where a and b are constants based on the properties of the gas being used. Since CO₂ is a gas composed of polar molecules, the van der Waals constant, "a," is nonzero, while the van der Waals constant, "b," accounts for the size of the gas molecules and is also nonzero for CO₂.

Using the van der Waals equation:

(P + an²/V²)(V - nb) = nRT

Solve for P. The value of a and b are 3.59 L²-atm/mol² and 0.0427 L/mol, respectively. Plug in the given values:

P = (nRT/(V - nb)) - (an²/V²)(a)

P = ((0.467 mol * 0.08206 L-atm/mol-K * (159°C + 273.15 K))/(0.245 L - (0.0427 L/mol * 0.467 mol))) - ((3.59 L²-atm/mol² * 0.467 mol²)/(0.245 L)²)(b)

P = 9.44 atm (approximately)

c) The van der Waals equation is an improvement over the ideal gas law because it accounts for the volume of the molecules and the attractive and repulsive forces between them that become significant at high pressures and low temperatures. At low pressures and high temperatures, the ideal gas law works well since the forces between molecules are negligible and the volume of the molecules is relatively small. However, at high pressures and low temperatures, the volume of the molecules and the attractive forces between them become significant, resulting in the deviation of gases from ideal behavior.

d) In this case, the correction for the volume of the molecules (represented by "b") is more significant than the correction for the attractive forces between molecules (represented by "a"). This is because the volume correction is proportional to the amount of gas, while the correction for the attractive forces is proportional to the square of the amount of gas. Since the amount of gas is relatively small compared to the square of the amount of gas, the correction for the volume of the molecules is more significant.

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The velocity of the goldfish is 40 centimeters per second (40 cm/s).Answer: 40

Velocity is the rate at which an object moves in a certain direction. The goldfish in question moved a distance of 8 centimeters in 0.2 seconds at a constant velocity. The velocity of the goldfish can be calculated by dividing the distance covered by the time taken. In this case, we will divide the distance covered, 8 centimeters by the time taken, 0.2 seconds. Hence: Velocity = Distance/TimeVelocity = 8 cm/0.2 s Velocity = 40 cm/sTherefore, the velocity of the goldfish is 40 centimeters per second (40 cm/s).Answer: 40

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Answer:

\(c. \: 100\)

Explanation:

cent means “one hundredth”.

the meter is the base unit.

cent is a hundredth.

so there are 100 centimeters in a meter.

Answer: the answer is c which is 100 .

Explanation: as cent means one hundredth . This tells us that there is 100 centimeters in a meter . To convert 100 cm to meters, we multiply 100 with 0.01, which gives us a result of 1 m. Let's convert 100 cm to meters. Thus, 1 cm = 1/100 m or 0.01 m. Hence, to get the value of 100 cm in terms of 'meter', we multiply it with 0.01. HOPE IT HELPS .PLEASE GIVE BRAINLIEST .THANKS .

After 14.4 seconds, 12.5g of a 50g nitrogen sample are still present.

Half-life is the length of time that it takes for half of an unstable nucleus to go through its decay. The half-life of each chemical varies. Because carbon-10's half-life is so short (19 seconds), it is not possible to find this isotope in nature.

The Foundational Elements. A half-life is the duration needed for something to reduce in quantity by half. The phrase is most frequently used in reference to radioactive decay, which takes place when unstable atomic particles shed energy.

\(N(t) = N_0 (1/2)^(t/t_1/2})\)

N(t) = quantity of the substance remaining

N₀ = initial quantity of the substance

t = time elapsed

t1/2 = half life of the substance

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Answer:

2Mg+O2 = 2MgO is the balanced equation of this reaction. When Mg +O2 reacts MgO is formed. The number of atoms of each element on reactant and product side must be equal

Explanation:

Ur welcome

Answer:

2Mg+O2 ⇒ 2MgO

Answer: 2. 37Ca.

Explanation:

The missing components of the neutralisation reaction include the following:

Neutralisation reaction is defined as the type of reaction that leads to the formation of salt and water when an acid and a base reacts.

From the reactions given the missing components are replaced as follows:

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To draw up a 28-mEq dose of sodium chloride at a concentration of 4-mEq/mL, you would need to draw up C" 7.0 mL.

To determine the amount of sodium chloride needed, you can use the formula:

Volume = Dose / Concentration

In this case, the dose is 28 mEq and the concentration is 4 mEq/mL. By substituting these values into the formula, we get:

Volume = 28 mEq / 4 mEq/mL = 7 mL

Therefore, you would need to draw up 7.0 mL of the 4-mEq/mL sodium chloride solution to obtain a 28-mEq dose.

Option C is the correct answer.

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Answer:

5.0000 I think this answer so mark be brainlist

The reaction in question is the preparation of aspirin, which involves the acetylation of salicylic acid using acetic anhydride as the acetylating agent.

The typical reaction conditions involve heating the mixture in a water bath at 50 degrees Celsius. However, in this case, the student used a higher temperature of 90 degrees Celsius.

The first observation is that the test for the presence of phenols using ferric chloride was negative.

Ferric chloride is commonly used as a reagent to detect the presence of phenols, which usually results in a color change (such as a purple or green color) due to the formation of a complex between the phenol and ferric chloride. The lack of color suggests the absence of phenols in the final product.

The second observation is the melting point of the dry product, which was measured to be 122-125 degrees Celsius. The expected melting point range for pure aspirin is typically around 128-137 degrees Celsius. The measured melting point falls within a slightly lower range.

Now, let's explain these results based on the experimental conditions and the reaction mechanism:

Reaction temperature: The student used a higher temperature of 90 degrees Celsius instead of the recommended 50 degrees Celsius. The elevated temperature can accelerate the reaction rate.

However, the acetylation of salicylic acid with acetic anhydride is an exothermic reaction, meaning it releases heat. The higher temperature might have caused the reaction to proceed more rapidly, potentially resulting in a shorter reaction time.

Effect on phenols: The higher temperature and shorter reaction time might have impacted the acetylation process.

Phenols, including salicylic acid, can undergo various side reactions under harsh conditions.

For example, at higher temperatures, phenols can undergo oxidation or other degradation reactions. It is possible that the elevated temperature affected the formation or stability of phenols in the reaction mixture, leading to a negative ferric chloride test.

Melting point: The slightly lower measured melting point of the dry product could be attributed to impurities or incomplete reaction.

The reaction might not have proceeded to completion, leading to the presence of impurities or unreacted starting materials in the final product. These impurities can lower the melting point range compared to pure aspirin.

Overall, the higher reaction temperature might have affected the formation of phenols and potentially led to incomplete or degraded products.

The negative ferric chloride test suggests the absence of phenols, while the slightly lower melting point could indicate the presence of impurities or unreacted starting materials.

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Answer:

The answer would be 4.5 moles of O2

Answer:A

Explanation: Since the boiling point is 212. As salt keeps getting added the boiling temperature keeps going up. Meaning it will boil at a high temp.

Answer:

80,000km/h

Explanation:

Answer: 12.5 hope this is right.

Explanation:

It is not possible to calculate the molarity of oxygen in water based on the given information.

To calculate the molarity of a solute in a solution, we need to know the number of moles of the solute and the volume of the solution.The problem statement provides the volume of oxygen gas (1.75 L) but does not provide information on the number of moles of oxygen gas or the volume of water.

Additionally, we would need to know if any oxygen gas has actually dissolved in the water to form a solution.Therefore, we cannot calculate the molarity of oxygen in water based on the given information.

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Answer:

ionic bond

Explanation:

Answer:

diffusion

Explanation:

Diffusion can be defined as the net movement of particles from a high concentration to a low concentration. This sounds like the most plausible word in this case.

Answer:

1

Explanation:

M r ( NaCl ) = A r ( Na ) +  A r ( Cl )  =  23 + 35,5  =  58,5

 So, 1 mol of NaCl has a mass of 58,5 g.

Moles of NaCl  =  58,5 g NaCl

times (x)

1 mol NaCl  = 58,5 g NaCl  =  1,00 mol NaCl

According to the mole concept, there are 0.140 moles in teaspoon of salt that contains 5 g.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.Number of moles is calculated as, mass/molar mass.

In this case number of moles is calculated as, 5/35.5=0.140 moles.

Thus, there are 0.140 moles in 5 g teaspoon of salt.

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Answer:

no the rock was formed before the layers that we life on today

Explanation:

Answer:

.....false

Explanation:

the particles in the air are packed apart whereas the particles in steel are closely packed and sound travel faster in solids than in gasses..

Answer:

False

Explanation:

The speed of sound is quickest in mediums that have their molecules close apart.  The speed of sounds is quickest in solids, followed by liquids, and slowest in gasses.  The close the molecules are together, the quicker sound travels.  The sound would travel faster in the steel than in the air.

This is due to the fact that sound waves are compression waves.  This means that they rely on the way molecules collide with one another and act sort of like a spring.  

Fun fact: In the old days, people used to put their ears to the train tracks to see if a train is coming.  Sound moves so fast in metal that they can sense the vibrations miles before the train arrived.

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Answer:

10

Explanation:

Atomic number = No. of protons

Therefore, the number of protons of an element with an atomic number of 10, is also 10.

The electropositive ion that is least likely to get reduced is Zn²⁺ (option B).

Electropositivity in chemistry is tendency of an element to release electrons to form a chemical bond or positively charged cations.

Electropositivity is primarily exhibited by metallic elements, especially the alkali metals and the alkaline earth metals.

Electropositivity is the opposite of electronegativity, which is a measure of the tendency of an atom to gain electrons and form negatively charged anions. Therefore, highly electropositive elements have very low electronegativities and vice versa.

Based on the cations given in this question, zinc (Zn²⁺) is the most electropositive, hence, has the least tendency to be reduced i.e. gain electrons.

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Answer: The given statement is True.

Explanation:

The heat will move from hotter object to the cooler object in search of thermal equilibrium. Heat transfer will only stop when both the bodies are at the same temperature.

Heat transfer can be done using conduction , convection or radiation.

The statement that Heat transfer is the movement of heat from a hotter object to a cooler object is True.

Answer:

It is A, A solution with as much dissolved solute as it can hold at a given temperature.

Explanation:

A saturated solution may be characterized as a solution with as much dissolved solute as it can hold at a given temperature. Thus, the correct option for this question is A.

The characteristics of the saturated solution are as follows:

According to the context of this question, a solution that holds less dissolved solute than is possible at a given temperature represents the properties of an unsaturated solution that does not form any kind of bubbles. For example, sodium chloride in water.

Therefore, a saturated solution may be characterized as a solution with as much dissolved solute as it can hold at a given temperature. Thus, the correct option for this question is A.

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