Why do thermistors increase in conductivity when heated? What happens in normal metals? Explain on the atomic level.

Molecular substances tend to be gases because the intermolecular forces of attraction are comparatively weak. You don't have to break any covalent bonds in order to melt or boil a molecular substance.

The longest intermolecular separation and hence the strongest intermolecular pressure of attraction can be found in the gaseous state of matter.

Although solids' intermolecular interactions were sufficient to maintain themselves in locked places, gases often have weak intermolecular forces that cause them to remain considerably separated. The gases possess greater intermolecular space than solids as a result of these weak forces.

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To balance a redox reaction, the increase and decrease in oxidation numbers must be balanced.

A redox reaction also called an oxidation- reduction reaction is a chemical reaction in which there is simultaneous gain and loss of electrons.

So, to balance a redox reaction, the simultaneous gain and loss of electrons must be balanced.

Thus, to balance a redox reaction, the increase and decrease in oxidation numbers must be balanced.

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Answer: The growth of the plant decides on the presence of plant hormone, auxin which develops in the roots and shoots. Auxins change the rate of elongation in plant cells, controlling how long they become. So, if the tips are removed, there is no auxin made and growth of the plant stops.

Answer: Well 0-7 is acid, and 0-3 is a strong acid. 4-7 is a weak acid. 8-11 is strong base. 12-14 is weak base!

Explanation:

Answer:

When ionic compounds dissolve in water they go through a process called dissociation, splitting into the ions that make them up. However, when you place covalent compounds in water, they typically do not dissolve but form a layer on top of the water.

Answer:

Dinitrogen pentoxide also known as Nitrogen pentoxide or nitric anhydride (these are all the same thing just different names people call them)

Answer:

The correct answer choice is A. A chemical change has occurred because new compounds have been produced.

Explanation:

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.Example: Melting of ice A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.Example: photosynthesis

Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.

Thus the true statement is a chemical change has occurred because new compounds have been produced.

The rate constant for the decomposition of ethanol on an alumina surface is 24.00 × 10²⁵ M.

The rate law is: rate = 24.00 × 10²⁵ M/s

The integrated rate law is: [C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t

If the initial concentration of C₂H₅OH was 1.25 × 10²² M, the half-life is 2.60 × 10⁻⁵ s.

The time required for all the 1.25 × 10²² M C₂H₅OH to decompose is 5.21 × 10⁻⁵ s.

Let's consider the decomposition of ethanol on an alumina surface.

C₂H₅OH(g) ⇒ C₂H₄(g) + H₂O(g)

The plot of [A] vs time (t) resulted in a straight line, which indicates that the reaction follows zero-order kinetics.

The slope, 24.00 × 10²⁵ M/s, represents the rate constant, k.

It is a chemical reaction in which the rate of reaction is constant and independent of the concentration of the reacting substances

The rate law for zero-order kinetics is:

rate = 24.00 × 10²⁵ M/s

The integrated rate law for zero-order kinetics is:

[C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t

Is the time for the amount of substance to decrease by half.

If the initial concentration of C₂H₅OH was 1.25 × 10²² M, we can calculate the half-life [t(1/2)] using the following formula.

t(1/2) = [C₂H₅OH]₀ / 2 × k

t(1/2) = (1.25 × 10²² M) / 2 × (24.00 × 10²⁵ M/s) = 2.60 × 10⁻⁵ s

We can calculate the time required for all the 1.25 × 10²² M C₂H₅OH to decompose using the integrated rate law.

[C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t

0 M = 1.25 × 10²² M - 24.00 × 10²⁵ M/s × t

t = 5.21 × 10⁻⁵ s

The rate constant for the decomposition of ethanol on an alumina surface is 24.00 × 10²⁵ M.

The rate law is: rate = 24.00 × 10²⁵ M/s

The integrated rate law is: [C₂H₅OH]t = [C₂H₅OH]₀ - 24.00 × 10²⁵ M/s × t

If the initial concentration of C₂H₅OH was 1.25 × 10²² M, the half-life is 2.60 × 10⁻⁵ s.

The time required for all the 1.25 × 10²² M C₂H₅OH to decompose is 5.21 × 10⁻⁵ s.

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The molarity of the NaOH solution required for the reaction is 0.186 M

We'll begin by writing the balanced equation for the reaction

H₂C₂O₄ +2NaOH —> Na₂C₂O₄ + 2H₂O

From the balanced equation above,

The mole ratio of the acid, H₂C₂O₄ (nA) = 1

The mole ratio of the base, NaOH (nB) = 2

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

Volume of the acid, H₂C₂O₄ (Va) = 22.14 mL

Molarity of the acid, H₂C₂O₄ (Ma) = 0.105 M

Volume of the base, NaOH (Vb) = 25 mL

MaVa / MbVb = nA/nB

(0.105 × 22.14) / (Mb × 25) = 1/2

2.3247 / (Mb × 25) = 1/2

Cross multiply

Mb × 25 = 2.3247 × 2

Mb × 25 = 4.6494

Divide both side by 25

Mb = 4.6494 / 25

Therefore, the molarity of the base, NaOH solution is 0.186 M

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Answer:

Answer E.

For a collision to be completely elastic, there must be NO LOSS in kinetic energy.

We can go through each answer choice:

A. Since the ball rebounds at half the initial speed, there is a loss in kinetic energy. This is NOT an elastic collision.

B. A collision involving sticking is an example of a perfectly INELASTIC collision. This is NOT an elastic collision.

C. A reduced speed indicates that there is a loss of kinetic energy. This is NOT elastic.

D. The balls traveling at half the speed after the collision indicates a loss of kinetic energy, making this collision NOT elastic.

E. This collision indicates an exchange of velocities, characteristic of an elastic collision. We can prove this:

Let:

m = mass of each ball

v = velocity

We have the initial kinetic energy as:

KE = \frac{1}{2}mv^2 + 0 = \frac{1}{2}mv^2KE=21mv2+0=21mv2

And the final as:

KE = 0 + \frac{1}{2}mv^2 = \frac{1}{2}mv^2KE=0+21mv2=21mv2

Answer:

E

Explanation:

hope this helps

Answer:

3.5154 g/mL

Explanation:

You will need to use the equation Density = Mass/Volume. You are given mm(can be used to find volume) of a cube and kg(mass). Since your answer is in g and mL we should convert it to those sizes. First we want cm so we will divide the 127.58 mm to cm getting 12.758 cm. We want to cube it since we are finding the whole area of a cube( 12.758*12.758*12.758) which will equal 2076.58 cm^3. We know that 1 mL is equal to 1 cm^3, so we can take our 2076.58 cm^3 and label them as mL(which is what we want). Then we know that there are 1000g in 1 kg, so if we multiply the 7.3 kg, we get 7300g. Finally use the equation Density = Mass/Volume to get your answer. 7300g/2076.58mL = 3.5154 g/mL.

Hope this helps!

Answer:

1. How many moles of oxygen will occupy a volume of 2.5 liters at 1.2 atm and 25° C? PV = V (1.2 n. 0821) (298) = 123 mols 2.

2.0 moles of oxygen gas will occupy a volume of 6.67 L at the same temperature and pressure.

Moles is a unit of measurement used in chemistry to express the amount of a substance. It is a counting unit that represents the number of particles, such as atoms, molecules, or ions, in a given sample.

One mole of a substance is defined as the amount of that substance that contains Avogadro's number of particles, which is approximately 6.022 x 10²³. This number is based on the concept that atoms, molecules, and ions are extremely small and difficult to count individually, so using moles allows for a more practical and convenient representation of quantities.

Given:

Moles of oxygen gas (initial) = 0.45 mol

Volume of oxygen gas (initial) = 1.5 L

Moles of oxygen gas (final) = 2.0 mol

Volume of oxygen gas (final) = ?

Using the principle of molar volume, we can set up the following ratio:

(0.45 mol / 1.5 L) = (2.0 mol / V)

V = (1.5 L × 2.0 mol) / 0.45 mol

V = 6.67 L

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The balance chemical equation and the type of reaction of AgNO₃ and the other compounds can be represented as follows;

2AgNO₃ + Cu → Cu(NO₃)₂ + 2Ag (single displacement )

2AgNO₃ → 2Ag + O₂ + 2NO₂ (decomposition reaction)

AgNO₃ + KCI → AgCI + KNO₃(double displacement reaction)

2Ag + I₂ → 2AgI (synthesis reaction)

AgNO₃ + Cu → Cu(NO₃)₂+ Ag

The balance equation is as follows:

This is a single displacement (substitution)  reaction. The Copper substance displaced silver from it compound.  

AgNO₃ → Ag + O₂ + NO₂

The balance equation is represented as follows:

The reaction is a decomposition reaction. Silver nitrate was decompose to it individual constituent.

AgNO₃ + KCI → AgCI + KNO₃

The balance equation is represented as follows:

The reaction is a double displacement reaction. The  anions and cations of two different compound switch places, forming two entirely different compounds.

Ag + I₂ → AgI

The balance equation is as follows:

The reaction is a synthesis reaction. The individual elements combined to form a compound.

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Answer:

Radioactive material

Explanation:

Answer:

to break down sugar in the presence of oxygen to release energy in the form of ATP

Explanation: i just finished this chapter of the class

Answer:

clouds and precipitation that minimize temperature changes throughout the day

Explanation:

Answer:

It have 31 electrons

It have 31 electrons

Answer:

D

Explanation:

D is the correct answer due to the fact that they way they are connected has 2 purple atoms and 1 orange one. thus would create a 1:2 ratio with 1 orange atom and 2 purple atoms.

A would create a 2:3 ratio, B wouldn't create a ratio comparable to the others, and C creates a 1:1 ratio with a few purple atoms floating around them, making all of the answers except D invalid.

In the given figures, the name of the model representing a compound with a 1:2 is figure D.

Molar ration of any compound gives idea about the ratio of the concentration of given constituents present in that compound.

In the figure A molar ratio is 2:3, in figure B molar ratio of given constituents is not given because each molecule is composed of same types of atoms, in figure C molar ratio of given constitutes particles is 1:1 and in the figure D molar ratio of constituents is 1:2. Because in figure D, two atoms of one element and 1 atom of another element is present.

Hence, figure D is correct option.

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Answer:

At standard temperature and pressure, 44.8

Explanation:

Answer:

Hexenes + Dioxygen = Carbon Dioxide + Water

The reaction type is combustion.

Its reactants are Hexenes - C6H12 and Dioxygen - O2

its products are Carbon Dioxide - CO2 and Water - H2O

Explanation: This was my yesterdays class

Answer:

In oxidation reduction reactions, one species gets reduced by taking on electron(s) and another species gets oxidized by losing electrons. They also flow by a wire

Explanation:

Answer:

Just as the Moon orbits the Earth because of the pull of Earth's gravity, the Earth orbits the Sun because of the pull of the Sun's gravity. ... This happens because the Earth has a velocity in the direction perpendicular to the force of the Sun's pull.

Explanation:

Answer:

Explanation:

Since the moles of gas and temperature are held constant the new volume can be found by using the formula for Boyle's law

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question

P1 = 1 atm

P2 = 2.25 atm

V1 = 250 mL

We have

[tex]V_2 = \frac{250 \times 1}{2.25} = \frac{250}{2.25} \\ = 111.1111111...[/tex]

We have the final answer as

Hope this helps you