Why is the melting of ice not a chemical change?

Answer:

I  can answer some of these.

Explanation:

Q 36.  B. Is false.

Q. 37  C. is false.

Q. 28.

All the  numbers are 1.

Answer:1465k

Explanation:Find explanation in the attachment

Answer:

The correct answer is 1465K

Explanation:

The formula to be used here is that of Charles' law.

Charles' law states that the volume of an ideal gas is directly proportional to its absolute temperature (in kelvin), provided that pressure remains constant. From the law above we can deduce the formula below

V₁/T₁ = V₂/T₂

where V₁ is the initial volume (2.0 L)

T₁ is the initial temperature (293K)

V₂ is the final temperature (10.0L)

T₂ is the final temperature (unknown)

From the formula, it can be deduced that

T₂ = (T₁ × V₂) ÷ V₁

T₂ = (293 × 10) ÷ 2

T₂ = 1465K

The final temperature of the balloon after heating will be 1465K

These are two questions and two answers

Question 1.

Answer:

Explanation:

1) Data:

a) m = 9.11 × 10⁻³¹ kg

b) λ =  3.31 × 10⁻¹⁰ m

c) c = 3.00 10⁸ m/s

d) s = ?

2) Formula:

The wavelength (λ), the speed (s), and the mass (m) of the particles are reltated by the Einstein-Planck's equation:

3) Solution:

Solve for s:

Substitute:

To express the speed relative to the speed of light, divide by c =  3.00 10⁸ m/s

Answer: s = 7.33 × 10 ⁻³ c

Question 2.

Answer:

Explanation:

1) Data:

a) m = 45.9 g (0.0459 kg)

b) s = 70.0 m/s

b) λ =  ?

2) Formula:

Macroscopic matter follows the same Einstein-Planck's equation, but the wavelength is so small that cannot be detected:

3) Solution:

Substitute:

As you see, that is tiny number and explains why the wave nature of the golf ball is undetectable.

Answer: 2.06 × 10 ⁻³⁴ m.  

Answer:

b. cellulose

Explanation:

It is important fro the smooth function of the digestive tract.

Cellulose is an important indigestible carbohydrate in the diet. Option b is correct.

It is a complex polysaccharide composed of repeating units of glucose molecules linked together by β-1,4-glycosidic bonds. Cellulose is the main structural component of the cell walls of plants and is found in abundance in fruits, vegetables, grains, and other plant-based foods.

Unlike other carbohydrates like amylose (a type of starch) or glycogen (a storage form of glucose in animals), cellulose cannot be broken down by the digestive enzymes produced by humans and most animals. This is because mammals lack the necessary enzyme, cellulase, required to hydrolyze the β-1,4-glycosidic bonds in cellulose.

Although cellulose is indigestible by humans, it plays a crucial role in the diet. It provides dietary fiber, which is essential for maintaining a healthy digestive system. Dietary fiber adds bulk to the stool, helps regulate bowel movements, and promotes the growth of beneficial gut bacteria. Additionally, consuming foods rich in cellulose can aid in satiety and weight management since it takes longer to chew and provides a feeling of fullness.

In summary, cellulose is an important indigestible carbohydrate in the diet, providing valuable dietary fiber and promoting digestive health. While humans cannot digest cellulose directly, its presence in plant-based foods is essential for maintaining a balanced and healthy diet.

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a strong acid fully dissociates in water to form H+ ions in water while a weak acid only partially dissociates to form H+ ions in water

The principal difference between a strong and weak acid is that strong acids fully dissociate into the water and weak acids partially dissociate into water.

Acids are those substances that give protons when dissociate in water. Acids are substances whose pH is less than 7, and they are sour in taste.

Acids are of two types. Strong acids and weak acids. Weak acids have more pH than strong acids. They are partially ionized in an aqueous solution.

Examples of weak acids are formic acid, acetic acid, oxalic acids. Examples of strong acids are hydrochloric acid, hydrobromic acids, and nitric acid.

Thus, strong acids totally dissociate into the water, whereas weak acids only partially do. This is the main distinction between strong and weak acids.

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Answer:

32) A. 1

33) E. 2

34) C. 12

35) D. Sb₄O₆

Explanation:

32. N₂O₅ + __H₂O → 2HNO₃

left side: 2 H , 2 N, 6 O

right side: 2 H, 2 N, 6 O

Nothing needs to change, so put a 1

33. P₂O₅ + 3H₂O → __H₃PO₄

left side: 6 H, 2 P, 8 O

right side: 3 H, 1 P, 4 O

everything on the right needs to double, so put a 2

34. Sb₄O₆ + __HCl → 4SbCl₃ + 6H₂O

left side: 4 Sb, 6 O, 1 H, 1 Cl

right side: 4 Sb, 6 O, 12 H, 12 Cl

the H and Cl on the left both need to be multiplied by 12, so put a 12

35. ____ + 4NaOH → 4NaSbO₂ + 2H₂O

left side: 4 Na, 4 O, 4 H

right side: 4 Na, 10 O, 4 H, 4 Sb

the left side needs 6 more O and 4 Sb, so add Sb₄O₆

Answer:

The water is the solvent and the Carbon Dioxide is the Solute

Explanation:

The Carbon Dioxide is being dissolved into the Water. Solute is what is being dissolved, Solvent is what is doing the dissolving

Answer:

Explanation:

The dual behavior of subatomic particles as waves and particles is known as the wave - particle duality.

And this principle is the basis of the quantum theory.

Such principle is widely applied to the electrons; i.e., the electrons posses wave and particle propeties, which must be understodd as that some of their properties may be explained as if they were particles and others as if they were waves.

For example, from the particle point of view electrons have mass. You can find in internet that the mass of one electron is about 9.1093837015×10⁻³¹ kg or about 1/1836 times the mass of one proton.)

Since, the point of view of the wave characteristics, electrons have wavelength, Louis de Broglie deduced the equation that relates the wavelength and the mass, through this realtion:

         λ = h / mv

Answer:

Its atomic mass is 14 ( = 6 protons + 8 neutrons). In chemistry, the number of protons in an atom is more important than the number of neutrons. Scientists call the number of protons the "atomic number"

Explanation:

Answer:

Explanation:

ppm is a unit of concentration that means parts per million. In grams that is grams of solute per one million (10⁶) grams of solution.

Then, 15 ppm of benzene means that there are 15 grams of benzen in 1,000,000 grams of solution.

That leads to:

Multiplying numerator and denominator by 10⁻⁶ you find:

Simplifying:

Which is read as 1.0 g of the solution contains 15 × 10⁻⁶ g of benzene, i.e. the second answer choice.

Answer:

1.0 g of the solution contains 15 * 10^-6 g of benzene

Explanation:

ppm by definition is parts per million. In this context, that means there are 15 g of benzene in 1,000,000 mL of solution.

We are given a solution with a density of 1.00 g/mL meaning there is just 1 mL

So, because there is only 1 mL instead of 1,000,000 mL, we will have 15 x 10^-6 g of benzene present in 1 g of the solution.

Answer:

Explanation:

n refers to the principal quantum number, and l refers to the angular momentum or Azimuthal quantum number.

Principal quantum number (n) is used to indicate the main energy level of the electron. It may take whole numbers: 1, 2, 3, 4, 5, 6, 7, ...

Angular momentum or Azimuthal quantum number refers to the kind (shape) of the orbital. It can take numbers from 0 to n - 1.

So, if n = 1, l can only be 0; if n = 2, l can be either 0 or 1; if n = 2, l can be either 0, 1 or 2.

On the other hand, the shape of the orbitals is also representd by a letter. then there is a unique relation between the letter that represents the orbital and the angular quantum number which is:

letter       l number

s               0

p               1

d               2

f                3

The previous information is summarized in the next table:

n    possible l numbers          

1          0                                          

2         0, 1                                        

3         0, 1, 2                                    

4         0, 1, 2, 3                              

5        0, 1, 2, 3, 4

6        0, 1, 2, 3, 4, 5

7        0, 1, 2, 3, 4, 5, 6

As per the choices given in the question you have:

(a) 1 p is not possible because when n = 1 the only l number is 0 and it is an s orbital, but p ⇒ l = 1. Thus, this is a correct choice.

(b) 4s is possible since n = 4 permits l to be 0, 1, 2, and 3.

(c) 5f is possible since n = 5 permits l to be 0, 1, 2, 3, and 4.

(d) 2d is impossible since n = 2 permits l to be 0, and 1, but d ⇒ l = 2. Thus, this is other right choice.

The impossible combinations of n and I are 1p and 2d.

Quantum numbers describe the position of an electron in an atom. Four sets of quantum numbers are important when discussing electrons in atoms. These quantum numbers are;

Given the conditions, combinations of n and I where n = l are not allowed. Recall that s p d f corresponds to 0 1 2 3. As such, 1p and 2d are not allowed.

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Answer:Boron

Explanation:

it is element 5 represented by the letter B

Answer:

Boron.

Explanation:

Boron is fifth in the periodic table, and carbon is sixth. It goes: hydrogen, helium, lithium, beryllium, boron, carbon...

Answer:

B) 271 g.

Explanation:

k = ln(2)/(t1/2) = 0.693/(t1/2).

Where, k is the rate constant of the reaction.

t1/2 is the half-life of the reaction.

∴ k =0.693/(t1/2) = 0.693/(26.0 hours) = 0.02665 hour⁻¹.

kt = ln([A₀]/[A]),

where, k is the rate constant of the reaction (k = 0.02665 hour⁻¹).

t is the time of the reaction (t = 538 min = 8.97 hour).

[A₀] is the initial concentration of (As-76) ([A₀] = 344 g).

[A] is the remaining concentration of (As-76) ([A] = ??? g).

∴ (0.02665 hour⁻¹)(8.97 hour) = ln((344 g)/[A])

∴ 0.239 = ln((344 g)/[A]).

∴ 1.27 = ((344 g)/[A]).

∴ [A] = (344 g)/(1.27) = 270.88 g ≅ 271 g.

Answer:

3065.63 J = 3.066 kJ.

Explanation:

Q = m.c.ΔT,

where, Q is the amount of heat needed to warm Fe (Q = ??? J).

m is the mass of Fe (m = 125.0 g).

c is the specific heat capacity of Fe (c = 0.45 J/g.°C).  

ΔT is the difference in T (ΔT = final temperature - initial temperature = 78.0°C - 23.5°C = 54.5°C).

∴ Q = m.c.ΔT = (125.0 g)(0.45 J/g.°C)(54.5°C) = 3065.63 J = 3.066 kJ.

Answer:

B

Explanation:

This is due to the differences in the concentrations of the radioactive isotopes in the two containers of the same volume. In container A, with a higher density of atoms, there is a higher chance of a neutron released in the decay of one atom, hitting another atom and splitting it. This is in comparison to container B that has fewer atoms that are widely dispersed due to the lower density. Atoms in cointainer A will therefore decay faster (shorter half-life) than atoms in container B.

Answer:

b

Explanation:

Answer:

Explanation:

The pressure exerted by a liquid is equal to the pressure inside the liquid. This pressure is called hydrostatic pressure.

The equation to calculate the pressure inside a liquid (a fluid in general) is found by applying balance of forces inside a portion of liquid.

The equilibrium condition (net force = 0) and the definition of pressure (P = F/A) leads to:

Where, P is the pressure exerted by the liquid, p⁰ is the atmospheric pressure, ΔP is the difference in the pressure, ρ is the density of the liquid, g is the acceleration of gravity, and Δh is the change with depth.

Hence, the pressure exerted by a liquid varies jointly with the density of the liquid and the depth, meaning that it is proportional to the product of them both.

Therefore, the choice that represents this conditon is the second one: the pressure exerted by a liquid changes proportional to the depth and proportional to the density changes.

The pressure exerted by a liquid is proportional to the depth of the liquid and also proportional to the density of the liquid.

The pressure exerted by a liquid changes with depth and density in a predictable way. As you go deeper into a liquid, the pressure increases because there is more liquid above you exerting force due to gravity. This relationship is proportional to depth; specifically, pressure due to the weight of a liquid of constant density is given by the formula p = ρ gh, where p is the pressure, h is the depth of the liquid, ρ (rho) is the density of the liquid, and g is the acceleration due to gravity.

Similarly, the pressure exerted by a liquid also changes as the density of the liquid changes. If the density of the liquid increases, the pressure at a particular depth also increases. Thus, this relationship is proportional to density. Traveling up into the atmosphere demonstrates the effect density has on pressure because the density of the air begins to decrease with height, unlike in liquids where the density is often constant.

In summary, the pressure exerted by a liquid is proportional to both the depth and the density of the liquid. Therefore, the correct description of how pressure changes in a liquid is: proportional to depth; proportional to density.

Answer:

It is Promethium

Explanation:

Because they are chemical elements with atomic numbers 57 through 71

Answer:

The answer is B) Promethium

Explanation:

The Promethium is a chemical element of the periodic table whose symbol is Pm and its atomic number is 61 and is part of the group of lanthanide elements.

Lanthanides are a group of elements that are part of period 6 of the periodic table of the elements whose name comes from the chemical element lanthanum, which is included within this group, giving a total of 15 elements, from the element of atomic number 57 (lanthanum) to 71 (lutetium)

Answer:

=2.016 g/ mol

Explanation:

1 atom of hydrogen has an atomic mass of 1.008 g. Hydrogen molecule is made up of two atoms of hydrogen therefore, it has a mass of:

1.008 g × 2=2.016 g

1 mole of hydrogen gas contains the Avogadro's number of molecules.

Thus M =(L × 2.016g) =2.016g/mol

Answer:

Element: Hydrogen

Symbol: H2

Molecular weight: 2.016 g

Mass of one mole: 2.016 g/mol

Explanation:

Hello! The answers you are looking for are stated above, taken directly from the periodic table, with avogadro's rule applied. Thank you, hope this comes to your help!

Final answer:

The energy required to produce 1 mole of He+ ions is 567.07 kcal/mol and for He++ ions is 1255.07 kcal/mol. The total energy to produce He++ ions from neutral He atoms is 1822.14 kcal/mol.

Explanation:

To calculate the energy in calories required to produce 1 mole of He+ ions and He++ ions from neutral helium (He) atoms, we employ Bohr's equations which relate the energy levels of electrons in hydrogen-like atoms. The first ionization energy (I1) is the energy needed to remove one electron, resulting in a He+ ion, and the second ionization energy (I2) is the energy required to remove a second electron, creating a He++ ion. The given first ionization energy for He is 24.59 eV and the second is 54.42 eV. Since 1 eV is equivalent to 23.06 kcal/mol, we can convert these ionization energies into calories per mole. Thus,

Adding these two amounts gives us the total energy to produce 1 mole of He++ ions from neutral He:

Total energy = 567.07 kcal/mol + 1255.07 kcal/mol = 1822.14 kcal/mol

Remember, this calculation assumes that all atoms are initially at ground state and that we are dealing with a single mole of atoms.

Answer:

d  liquid

Explanation:

Bromine occurs in the liquid state at room temperature.

Bromine is the only nonmetallic element that occurs in the liquid state at room temperature.

Answer:

Explanation:

Ground-state is the configuration of the electrons when every electron of the atom occupies the lowest possible energy level.

The rank of energy of the orbitals may be remembered using Aufbau rules, and it is:

1s² < 2s² < 2p⁶ < 3s² < 3p⁶ < 4s² < 3d¹⁰ < 4p⁶ < 5s² < 4d¹⁰ < 5p⁶ < 6s² < 4f¹⁴ < 5d¹⁰ < 6p⁶ < 7s² < 5f¹⁴ < 6d¹⁰ < 7p⁶

Then, to find whether an electron configuration corresponds to a ground-state one, you must check that the previous order is preserved.

Option A). 1s² 1p⁶ 2d²

The orbital 1p does not exist. So this one is discarded.

Option B) 1s² 2s⁴ 2p⁶

The maximum number of electrons in an s orbital is 2, so 2s⁴ is impossible, and this option is discarded.

Option C) 1s² 2s² 2p⁵

This is correct because the orbitals are filled in the correct increasing energy order, without jumping any one.

Option D) 1s² 2s² 2d⁶

Orbital 2d does not exist, so this option is also discarded.

Answer:

Is one unified atomic mass unit (u)

Explanation:

It is NOT an atomic mass unit (amu). That unit is obsolete. It was based on oxygen and was replaced in 1961.

Answer:

Ph= 3

Explanation:

-Log(0.0010)=3

Answer:

i think 35 degrees Celsius

Explanation:

cause its the same temperature

Answer:

The answer is: A. 45 degrees Celsius

Explanation:

Answer:

In order to solve this problem, you need to know that an exothermic reaction is a chemical reaction that releases energy through light or heat to the environment, in the other hand, an endothermic reaction is a chemical reaction that absorbs heat from its environment.

In the problem says that an exothermic reaction is performed at a temperature of 35 degrees Celsius.

Now, keeping in mind that a exothermic reaction release heat, we can affirm that the temperature of the sistem will by increased after the reaction occurs.

Finally, the only possible answer is A, because is the only temperature which is superior to the initial temperature (35 degrees Celsius)

Answer:

The speed of an electron is 0.01908 m/s.

Explanation:

De-Broglie wavelength is given by:

[tex]\lambda=\frac{h}{mv}[/tex]

where,  [tex]\lambda[/tex] = wavelength of a particle

h = Planck's constant = [tex]6.626\times 10^{-34}Js[/tex]

m = mass of particle

v = velocity of the particle

Velocity of an electron = v

Mass of an electron = [tex]9.1\times 10^{-31}kg[/tex]

Wavelength of electron is twice the displacement in seconds which is velocity of an electron.

Then.wavelength of an electron = [tex]\lambda =2v[/tex]

[tex]\lambda =2v=\frac{6.626\times 10^{-34}Js}{9.1\times 10^{-31}kg\times v}[/tex]

v = 0.01908 m/s

The speed of an electron is 0.01908 m/s.

In quantum physics, the de Broglie wavelength exhibits the wave-particle duality of matter, presenting that particles like electrons have wave characteristics. If an electron's de Broglie wavelength is twice its displacement per second, it suggests the electron's velocity equals the de Broglie wavelength divided by twice the time.

The subject of the question pertains to de Broglie wavelength which is a fundamental concept in quantum physics. The de Broglie wavelength is named after Louis de Broglie and it describes the wave-particle duality of matter, suggesting that particles such as electrons have characteristics of both particles and waves.

If the de Broglie wavelength of an electron is twice its displacement in one second, this implies that the electron's velocity, is equal to the de Broglie wavelength of the electron divided by double the time (which is 1 second in this case).

It is important to understand that the de Broglie wavelength is not a physical wavelength but rather a mathematical construct that helps us understand the behavior of particles in a more intuitive way than through purely using the equations of quantum mechanics.

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Answer:

A higher concentration of a catalyst will speed up the reaction rate.

Answer:

increases reaction

Explanation:

the concentration of reactants generally increases the rate of reaction because more of the reacting molecules or ions are present to form the reaction products.

Answer:

b. re-absorption

Explanation:

Most of the water and other substances dissolved in the plasma returns to circulation during the process of re-absorption.

Re-absorption refers to the mechanism by which solutes and water moves out of the glomerular filtrate and back into the bloodstream.

Answer:

When the metal can exist in more than one oxidation state

Explanation:

The Metals of Tansição are hard and have high melting point and boiling. Because they are metals, they conduct heat and electricity well. They may form alloys, have varying oxidation states (oxidation states wider than elements of other groups) and usually indicate the oxidation state in their name.