can someone answer that for me​

Answer:

B

Explanation:

Protons are located in the nucleus, which takes out c

Electrons are in specific shells, so b is the answer

The hydroxide ion concentration, [OH-] = 2.439 x 10⁻¹⁰

Equilibrium of water and the ions :

[tex]\tt 2H_2O(l)\rightarrow H_3O^+(aq)+OH^-(aq)[/tex]

[tex]\tt Kc=\dfrac{[H_3O^+][OH^-]}{H_2O}[/tex]

Kc[H₂O] is the ion equilibrium constant for water ⇒ Kw.

The product of the concentrations of these ions (H₃O⁺ and OH⁻)at equilibrium at 25°C is 1.0 x 10⁻¹⁴ M

[H₃O⁺] [OH⁻] = 1.0 x 10⁻¹⁴ M = Kw

The hydrogen ion concentration of  [H⁺]=4.1 x 10⁻⁵ M, so  the hydroxide ion concentration, [OH-] :

[tex]\tt 4.1\times 10^{-5}\times [OH^-]=1.10^{-14}\\\\(OH^-]=\dfrac{1.10^{-14}}{4.1\times 10^{-5}}\\\\(OH^-]=2.439\times 10^{-10}[/tex]

Answer:

2.07 × 10³ cal

Explanation:

Step 1: Given and required data

Step 2: Calculate the change in the temperature experienced by the aluminum piece

ΔT = 92.0 °C - 37.0 °C = 55.0 °C

Step 3: Calculate the heat required (Q)

We will use the following expression.

Q = c × m × ΔT

Q = 0.215 cal/g.°C × 175 g × 55.0 °C

Q = 2.07 × 10³ cal

Answer:

A. Lower than

Answer:

Both diseases affect the control of voluntary muscles.

Explanation:

Parkinson's disease is a progressive brain disease that affects movement. It affects the nerve cells that produce dopamine in the part of the brain called substantia nigra. The symptoms include shaking, stiffness, and difficulty with walking, balance, and coordination. Symptoms get worse with time, often leaving people with difficulty walking and talking.

ALS (amyotrophic lateral sclerosis) is a progressive nervous system disease that affects nerve cells in the brain and spinal cord. The first symptoms usually involve muscle weakness, and as the disease progresses, it results in the loss of muscle control.

Scientists don't know the exact cause of these diseases. As the cause is not known, there is no exact way to prevent them. There is no cure for them, either. The treatment is focused on the management of symptoms.

This is why the third option is the correct one.

The energy levels of an atom is the quantized amount of energy found at different levels n = 1,2, 3 etc. Thus option B is correct.

Electrons in an atom are revolving around the nucleus through circular paths of fixed energy. These circular paths are called orbits and the different energy levels in these paths are called orbitals.

The quantized energy levels are termed as n = 1, 2, 3 that is lowest level to higher levels of energy. Electrons are able to transit between these energy levels.

Thus, a level of n=1 is the ground level or first energy level n =2 is second energy level and so on. These energy level cannot be fractions and therefore, they are said to quantised. Hence, option B is correct.

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Answer: n = 1, 2, 3,

a quantized amount of energy found at the different levels

Explanation:

There is a law called conservation of energy which states that energy can neither be created nor be destroyed. It can be only transferred from one form to another form. Therefore, the correct option is option A.

Energy transfer is a phenomenon in which energy transfer from one matter to another matter. Energy can be transferred in two forms that are by doing work or by transferring heat.

Heat can be transferred by three ways conduction, convention and radiation. In conduction, when two object are in direct contact, transfer of molecules takes place. The energy gained by the water will equal the energy lost by the surroundings.

Therefore, the correct option is option A.

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Answer:

12.9 L Kr

General Formulas and Concepts:

Chemistry - Gas Laws

Explanation:

Step 1: Define

0.575 mol Kr

Step 2: Identify Conversions

1 mol= 22.4 L at STP

Step 3: Convert

[tex]0.575 \ mol \ Kr(\frac{22.4 \ L \ Kr}{1 \ mol \ Kr} )[/tex] = 12.88 L Kr

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

12.88 L Kr ≈ 12.9 L Kr

Answer:

I believe the answer is Reflecting Telescope

Explanation:

-leeknowishawt

first we find the mass of the final solution

we know that

density=mass/volume

we know the density and volume

1=m/100

m=100g

now we calculate the mass ofNa2CO3

2% of 100 is equal with 2g of Na2CO3

Answer:

i dunno

Explanation:

Answer:

Explanation:

Evidence for early forms of life comes from fossils. By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth. There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind.

Answer:

There are  

4.517

⋅

10

23

atoms of Zn in 0.750 mols of Zn.

Explanation:

Since we know that there are  

6.022

⋅

10

23

atoms in every mole of a substance (Avogadro's Number), there are  

6.022

E

23

⋅

0.750

atoms of Zn in 0.750 mols of Zn.

Answer:

There are  4.517 ⋅ 10  23 atoms of Zn in 0.750 mols of Zn. have a good day:)

Explanation:

Answer:

pH = 4

Explanation:

Step 1: Given data

Concentration of H⁺ ions in the solution ([H⁺]): 10⁻⁴ M

Step 2: Calculate the pH of the solution

We will use the definition of pH.

pH = -log [H⁺]

pH = -log 10⁻⁴ M

pH = 4

The pH of the solution is 4. Considering the pH scale, given the pH is lower than 7, the solution is acidic.

Answer:

0.2330 grams of solid KCl

Explanation:

In order to find KCl in grams, we need to convert from moles to moles to grams..

However, we are given the volume and the molarity, so first we will use that to convert to moles of AgNO3 (silver nitrate) and then use that to convert to moles of KCl and finally to grams of KCl..

-----------------------------------------------------------------------------------------------------------------

Step 1 -> We need to convert milliliters to liters

(25.0 ml)([tex]\frac{1 L}{1000 mL}[/tex]) = 0.025 L

Step 2 -> Convert from liters and molarity to just moles of AgNO3

(0.025 L)(0.125 [tex]\frac{moles AgNO_{3} }{1 ln soln}[/tex])  =  0.003125  moles [tex]AgNO_{3}[/tex]

**Liters cancel out, so just multiply across...

Step 3 -> Now that we have moles of AgNO3, we will convert to moles of KCl

We will do this using the balanced equation

We see that in the balanced equation, for every mol of AgNO3 that reacts, one mol of KCl will react too. So we will set the dimensional analysis up like the following:

(0.003125 moles AgNO3) * [tex]\frac{1 mol KCl}{1 mol AgNO3}= 0.00312 mol KCl[/tex]

Step 4-> So now that we have moles of KCl, we will just convert to grams

We will do this using the molar mass (atomic mass) of KCl to convert to grams

0.00312 mol KCl * [tex]\frac{74.5513 grams KCl}{1 mol KCl} = 0.2329728125 grams of KCl[/tex]

This can be rounded to 0.2330 grams of KCl

The enthalpy change accompanying the reaction of 0.95 g of S is -11.85 kJ

Given

ΔH° for the reaction is -790 kJ

Required

The enthalpy change

Solution

Reaction

2S (s) + 3O₂(g) = 2SO₃ (g)

mol of S(MW=32 g/mol) :

[tex]\tt mol=\dfrac{0.95}{32}=0.03[/tex]

For 2 mol S, the entalphy = -790kJ

The enthalpy change for 0.03 mol :

[tex]\tt \dfrac{0.03}{2}\times -790~kJ=-11.85~kJ[/tex]

The enthalpy change accompanying the reaction will be "-11.85 kJ".

Given:

Value of ΔH°,

According to the question,

→ [tex]2S(s) +3O_2(g) =2SO_3(g)[/tex]

Mol of S will be:

= [tex]\frac{0.95}{32}[/tex]

= [tex]0.03[/tex]

hence,

The enthalpy change for 0.03 mol will be:

= [tex]\frac{0.03}{2}\times -790[/tex]

= [tex]-11.85 \ kJ[/tex]

Thus the answer above is correct.

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Answer:

B.

Explanation:

The two reactions shown in the attached image depicts the processes of photosynthesis and cellular respiration. Photosynthesis is the process whereby autotrophic organisms use CO2 (carbon dioxide) and H2O (water) in the presence of sunlight to make glucose (C6H12O6). The equation is as follows:

6CO2 + 6H2O + sunlight → C6H12O6 + 6O2

On the contrary is the process of cellular respiration, which involves the breakdown of glucose (sugar) in order to release energy (ATP). The equation is as follows:

C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

According to this question, the option B which says that "Sugar is broken down to release energy" is CORRECT.

Answer:

1.3×10²³ formula unit

Explanation:

Given data:

Mass of CaCl₂ = 23.8 g

Number of formula unit = ?

Solution:

Number of moles = mass/molar mass

Number of moles = 23.8 g/110.98 g/mol

Number of moles = 0.21 mol

1 mole of any substance contain 6.022×10²³ formula unit

0.21 mol × 6.022×10²³ formula unit / 1mol

1.3×10²³ formula unit

Answer:

The negative charges of the surface will be attracted to the positive ends of the water molecule

Explanation:

A water molecule is a polar molecule. This means that the two ends of a water molecule are oppositely charged with one end being positive and the other end being negative.

When the positive end of a water molecule encounters a surface as shown in the attachment, where positive and negative charges are evenly distributed at rest, with the negative charges free to move, the negative charges will be attracted to the positive end of the water molecule due to the principle of electrostatics which states that unlike charges attract, while like charges repel. This means that negative and positive charges are attracted to each other while positive and positive or negative and negative charges are repelled from each other. Therefore, the water molecule will adhere to the surface because of the attraction between opposite charges.

The unlike charges will attract as expected based on the laws of electrostatics.

According to the laws of electrostatics, like charges repel while unlike charges attract. We are told in the question that water is a polar molecule with a positive and a negative end.

If the positive end of water dipole approaches the negative charges on the surface, the unlike charges will attract as expected based on the laws of electrostatics.

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Answer:

The answer is: 5co2

Answer:

40g

Explanation:

Given parameters:

Number of moles  = 1mol

unknown:

mass of Ca  = ?

Solution:

The number of moles of a substance is related to mass using the expression below;

    Mass = number of moles x molar mass

Molar mass of Ca = 40g/mol

     So;

          Mass of Ca = 1 mol  x 40g/mol  = 40g

Answer:

they must have same atomic number and different atomic mass

Answer:

C . Gravitational force

Explanation:

Answer:

Gravitational force

Explanation:

Gravitational force is commonly known as gravity or gravitation, which  is a force that exists between all the objects present in this universe. For any two objects or particles having non-zero mass, a force of gravity exists between the which tends to attract them towards each other.

Answer:

HNO3

Explanation:

HNO3 is nitric acid. Nitric acid as a compound contains Hydrogen, Nitrogen and Oxygen molecules, therefore its chemical formula is HNO3. Very useful for fertiliser and chemical making. This acid can be manufactured from ammonia and it is a very important chemical that is used for manufacturing fertilizers.

Nitric acid is useful for the manufacturing of ammonium nitrate and calcium ammonium nitrate which have uses as fertilizers.

Answer:

when the Moon moves into the Earth's shadow

when the Sun, Earth, and Moon are exactly or very closely aligned with the Earth between the other two, and only on the night of a full moon

Explanation:

CnHm is the general closed chemical formula of liquid hydrocarbons used as a fuel in the internal combustion engines. However, hydrocarbons consist of hydrogen and carbon and also small amounts of O2, H2, S, H2O, and some metals containing crude oil derivatives .

Answer:

7

Explanation: