What are the differences between an endothermic and exothermic reaction?

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 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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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:

B. Determine the amount of phosphorus in each sample.

D. Determine the number of different types of monomers in each sample.

Answer:

A and B

Explanation:

A and B are useful in correctly identifying the samples as the nitrogen content can be used to determine if the sample is a protein, and the phosphorus content can be used to determine if the sample is a nucleic acid. These two tests would allow the scientist to differentiate between the two types of biomolecules.

C5H12 + O2 → H2O + CO2 this reaction is complete combustion reaction. Because carbon dioxide and water are formed as a product.

The Combustion defined as a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, normally atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.

C5H12 + O2 → H2O + CO2 Pentane undergoes a complete combustion reaction with excess oxygen to give carbon dioxide and water.

Thus, this reaction is complete combustion reaction. Because carbon dioxide and water are formed as a product.

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The conversion factors are, a. 1 kilometer = 1000 meters, 1 meter = 0.001 kilometers b. 1 liter = 1,000,000 microliters, 1 microliter = 0.000001 liters c. 1 second = 1000 milliseconds, 1 millisecond = 0.001 seconds

Here are the conversion factors for each pair of units:

a. Meters and kilometers:

1 kilometer = 1000 meters

1 meter = 0.001 kilometers

b. Liters and microliters:

1 liter = 1,000,000 microliters

1 microliter = 0.000001 liters

c. Seconds and milliseconds:

1 second = 1000 milliseconds

1 millisecond = 0.001 seconds

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The molar mass of the unknown acid is 120.4 g/mol.

How to calculate the number of moles in potassium hydroxide solution?

We can use the volume and concentration of the potassium hydroxide solution to determine the number of moles of KOH that were added to the acid sample:

moles of KOH = volume of KOH solution (L) x concentration of KOH solution (mol/L)

moles of KOH = 29.69 mL x (1 L / 1000 mL) x 0.1453 mol/L

moles of KOH = 0.004307 moles

Since the acid is monoprotic, the number of moles of KOH added is equal to the number of moles of acid present in the sample. We can use this information to calculate the molar mass of the acid:

moles of acid = moles of KOH = 0.004307 moles

molar mass of acid = mass of acid (g) / moles of acid

We know that the mass of the acid sample is 0.5191 g, so we can substitute this value into the equation:

molar mass of acid = 0.5191 g / 0.004307 mol

molar mass of acid = 120.4 g/mol

Therefore, the molar mass of the unknown acid is 120.4 g/mol.

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The three ways to increase the rate of calcium carbinate and hydrochloric acid are decreasing pressure, increasing temperature and use of catalyst.

Pressure is defined as the force applied on an object perpendicular to it's surface per unit area over which it is distributed.Gauge pressure is a pressure which is related with the ambient pressure.

There are various units by which pressure is expressed most of which are derived units which are obtained from unit of force divided by unit of area . The SI unit of pressure is pascal .

It is a scalar quantity which is related to the vector area element with a normal force acting on it.It is distributed over solid boundaries and across arbitary sections of fluid normal to the boundaries at every point.

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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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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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Answer:

it will take 100 seconds for 17.2% of the reactant to remain.

Explanation:

This is a first-order reaction, which means the rate of the reaction is proportional to the concentration of the reactant. The half-life (T1/2) of a first-order reaction can be calculated as follows:

T1/2 = ln(2) / k

Where k is the rate constant.

So, the half-life of the reaction at 400 ∘C can be calculated as follows:

T1/2 = ln(2) / 0.0340 s−1 = 20.3 s

To find the time it takes for 17.2% of the reactant to remain, we can use the formula:

[A]t = [A]0 * e^(-kt)

Where [A]t is the concentration of the reactant at time t, [A]0 is the initial concentration of the reactant, k is the rate constant, and t is the time.

We want to find t such that [A]t = 0.172 * [A]0. Taking the natural logarithm of both sides:

ln([A]t / [A]0) = -kt

ln(0.172) = -k * t

t = -ln(0.172) / k = -ln(0.172) / 0.0340 s−1 = 100 s

So, it will take 100 seconds for 17.2% of the reactant to remain.

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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[tex]2H_2 + O_2\rightarrow 2H_2O[/tex]

From the balanced chemical equation, we know that 2 moles of H2 is required to react with 1 mole of O2:

⇒ [tex]\dfrac{n_{H_2}}{2}=\dfrac{n_{O_2}}{1}[/tex]

We're also given that we have 0.37 moles of O2:

⇒ [tex]\dfrac{n_{H_2}}{2}=\dfrac{0.37}{1}[/tex]

Solve for moles of H2:

⇒ [tex]n_{H_2}=\dfrac{0.37}{1}*2\\\\n_{H_2}=0.74[/tex]

0.74 moles of hydrogen react with 0.37 moles of oxygen.

Answer:

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

Explanation:

Chymotrypsin is an enzyme and, as such, it possesses the following characteristics:

A. Is a catalyst: Enzymes are biological catalysts that speed up chemical reactions without being consumed or altered in the process.

C. Speeds up a chemical reaction: Enzymes work by lowering the activation energy required for a reaction to occur. This means that the reaction can occur more quickly and efficiently in the presence of an enzyme.

D. Is found in cells of some living organisms: Enzymes are found in the cells of living organisms, where they play a crucial role in many biological processes, such as digestion, metabolism, and DNA replication.

These characteristics are common to all enzymes, including chymotrypsin, which is a type of protease enzyme that is involved in breaking down proteins in the digestive system.

B. Inhibits the binding of a substrate to an active site: This statement is incorrect. Enzymes actually increase the rate of reaction by facilitating the binding of the substrate to the active site, where the reaction takes place. Inhibitors, on the other hand, can interfere with this binding and slow down the reaction.

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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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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All of the following are common symptoms of all dissociative disorders except A. Wandering away from home.

Dissociative disorders are a group of mental health conditions characterized by a disruption in one's normal sense of identity, consciousness, and perception. Although there are various types of dissociative disorders, they share several common symptoms. One of the most prominent symptoms of dissociative disorders is the experience of mental health problems, such as anxiety, depression, and post-traumatic stress disorder (PTSD). Individuals with dissociative disorders may also experience feelings of detachment or disconnection from themselves, their environment, and their emotions. This detachment can manifest as a sense of being outside oneself or as a feeling of numbness or emotional blunting. Another hallmark symptom of dissociative disorders is a blurred sense of identity, which may present as confusion about one's personal identity or amnesia for important life events. Finally, it is important to note that not all individuals with dissociative disorders will experience every symptom, and the severity of symptoms can vary widely between individuals.

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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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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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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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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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The mathematical representation of Charles's Law is V1/T1 = V2/T2.

What do you mean by Charles's Law?

Charles's Law, also known as the Law of Volume-Temperature, states that the volume of a gas is directly proportional to its temperature when pressure is held constant. In other words, as the temperature of a gas increases, its volume will also increase. It was first established by physicist Jacques Charles in 1787.

The mathematical representation of Charles's Law states that the ratio of the initial volume (V1) to the initial temperature (T1) is equal to the ratio of the final volume (V2) to the final temperature (T2). This means that, as the temperature of a gas increases, its volume will increase proportionally.

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Answer:

Molar mass of Cu(NO₂)2 = 187.5 g/mol

The theoretical yield of NO2 would be 22.08 grams.

Mole of 20.0 grams HNO3 = mass/molar mass

                                             = 20/63.01 = 0.32 mol

Mole of 20.0 grams NO = 20/30.01 = 0.67 mol

From the equation of the reaction, the mole ratio of HNO3 and NO is 2:1, thus, HNO3 is the limiting reactant.

The mole ratio of HNO3 and NO2 is 2:3, thus, the equivalent mole of NO2 formed would be:

3/2 x 0.32 = 0.48 mol

Mass of 0.48 mol NO2 = 0.48 x 46 = 22.08 grams

In other words, the theoretical yield of NO2 from the reaction is 22.08 grams.

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The cube has a volume of 3.4 cm³. The volume of an object or substance is the amount of space it occupies.

The volume of an object or substance is the amount of space it occupies. It is typically measured in cubic length units, such as cubic meters (m³), cubic centimeters (cm³), or cubic feet (ft³). Depending on the shape of the object, it can be calculated by multiplying the object's length, width, and height.

Calculating quantities like the volume of a container, the amount of a substance in a given space, and the displacement of fluids by solid objects are all based on the concept of volume, which is an essential one in engineering, physics, and mathematics.

A cube's volume is determined by cubing its edge length, so a cube with an edge length of 1.5 cm has the volume:

                       V = (1.5 cm)³

                            = 3.375 cm³

Rounding this to one decimal place gives:

                            V ≈ 3.4 cm³

So the volume of the cube is  3.4 cm³.

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Answer:

86 moles of H2O.

Explanation:

In the reaction 2 moles of NH3 reacts with 3 moles of CuO to produce 3 moles of Cu, 1 mole of N2 and 3 moles of H2O.

So, when 57 moles of NH3 are consumed, the amount of H2O produced will be 3 * 57 moles / 2 moles = 86 moles of H2O.

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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