On the periodic table, the period number can identify the number of energy levels an element will contain.


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Answer:

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Explanation:

Muy bien. Antes de responder lo que piden en el problema, vamos a calcular la concentración inicial de la solución A:

1) Concentración de la solución A:

En este caso, se sabe que se usaron 3,5 g de la sal, se puede calcular los moles usando el peso molecular y la masa:

n = m/PM  (1)

Aplicando tenemos:

n = 3,5 / 98 = 0,0357 moles

Conociendo los moles, podemos calcular la concentración:

M = n/V (2)

Aplicando la formula tenemos:

M = 0.0357 / 0.200 = 0.1785 M

Esta es la concentración del ácido etiquetado como "Solución A".

Ahora podemos ver la concentración de la solución B, para luego calcular las concentraciones molares de los iones en solución y sus respectivos pH.

2) Concentración del ácido en la solución B:

Con la concentración de "A", se puede determinar la concentración de la solución B. Aqui podemos esperar que sea un valor mas bajo, puesto que es una dilución la que estamos haciendo. Por lo tanto.

Si se toma 5.5 mL de la solución A, entonces:

n = 0.1785 * 0.0055 = 0.00098 moles

Con esto, se calcula la nueva concentración:

M = 0.00098 / 0.070 = 0.014 M

Esta es la concentración de la solución B. Ahora para calcular pH y concentraciones de los iones en equilibrio, hay que plantear la reacción acido base en equilibrio. Como es el mismo compuesto, usaremos la misma ecuación.

3) pH de las soluciones A y B:

Planteamos la reacción de equilibrio:

CH₃COO⁻ + H₂O <------> CH₃COOH + OH⁻     Kb

Calculando el Kb, sería asi:

Kb = Kw/Ka

Kb = 1x10⁻¹⁴ / 1.8x10⁻⁵ = 5.56x10⁻¹⁰

Ahora reescribimos la ecuación y hacemos una tabla de equilibrio:

       CH₃COO⁻ + H₂O <------> CH₃COOH + OH⁻     Kb = 5.56x10⁻¹⁰

i)        0.1785                                    x              x

eq)    0.1785-x                                  x              x

Kb = [OH⁻] [CH₃COOH] / [CH₃COO⁻]

Reemplazando nos queda:

5.56 * 10⁻¹⁰ = x² / (0.1785-x)      

Y como Kb es muy pequeño, se asume que el valor de x será también pequeño, asi que podemos redondear la resta a simplemente 0.1785, quedando tan solo:

5.56 * 10⁻¹⁰ = x² / (0.1785)

x² = 5.56*10⁻¹⁰ * 0.1785

x = √9.9246*10⁻¹¹

x = 9.96*10⁻⁶ M

Esta es la concentración de [OH⁻] y [CH₃COO⁻] en la solución A.

Aplicando lo mismo para la solución B (Cambiando solo el dato de concentración) nos queda:

x = √5.56*10⁻¹⁰ * 0.014

Finalmente, para calcular pH, se calcula primero el pOH y luego el pH:

pH = 14 - pOH

pOH = -log[OH⁻]

Para la solución A:

pOH = -log(9.96*10⁻⁶) = 5

pH = 14 - 5

En el caso de la solución B:

pOH = -log(2.79*10⁻⁶) = 5.55

pH = 14 - 5.55

Espero te ayude

Answer:

Explanation:

The percentage error of a certain measurement can be found by using the formula

[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]

From the question we have

actual number = 0.95 g/mL

error = 0.95 - 0.56 = 0.39

We have

[tex]p(\%) = \frac{0.39}{0.95} \times 100 \\ = 41.0526315...[/tex]

We have the final answer as

Hope this helps you

Answer:

5

Explanation:

4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)

The law of conservation of energy can be applied to heat changes, ie the heat received/absorbed is the same as the heat released  

Q in = Q out  

Heat can be calculated using the formula:  

Q = mc∆T  

A calorimeter is a device used to measure the specific heat of material  

A metal is put into a calorimeter that contains water and there will be heat transfer:  

[tex]\tt \displaystyle m_mc_m (T_m-T)=m_wc_w(T-Tw)[/tex]

m = metal  

w = water  

T = the final temperature of the mixture  

mass of metal =(Nickel) = 4.94 g

mass of calorimeter = 12.5 g

mass of water = 123.13 g (135.63 - 12.5)

The equation

Q released (metal) = Q absorbed(calorimeter+water)

The equation :

4.94 x c . (Tm-23.6)=C.(23-6-21.9)+123.13 x c. (23.6-21.9)

Answer:

5

Explanation:

5

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 768 g

volume = 24 cm³

We have

[tex]density = \frac{768}{24} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

The density of wood is 32 g/cm³.

Explanation:

Given data:

Mass of wood = 768 g

Volume of wood = 24 cm³

Density of wood = ?

Solution:

Density is equal to the mass divided by its volume.

Formula:

d = m/v

d = density

m = mass

v = volume

d = 768 g/ 24 cm³

d = 32 g/cm³

The density of wood is  32 g/cm³.

Answer:

Disagree, the total mass is 245 grams.

Explanation:

We need to keep in mind the Law of Conservation of Mass. Each gram added to the lemonade (a system) will remain there unless it is somehow removed. The added mass of both sugar and lemon count for the total mass (210+20+15), even if the sugar was dissolved.

Answer:

1. Is fortnite travis scott burger

2. Beetlejuice the second

3. The measurement is 69420

Explanation:

my mom told me

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question

mass = 20 g

density = 5 g/cm³

So we have

[tex]volume = \frac{20}{5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer: In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other.

Explanation:  He called this movement continental drift.

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{4.5 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 7.47508...[/tex]

We have the final answer as

Hope this helps you

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. An element  cannot be broken down into simpler substances by a chemical change. The correct option is option A.

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

Element is the basic unit of any compound and molecule which can not be broken further. Mixture, solution and compound are composed of two or more than two elements which can be further broken down easily.

Therefore, an element  cannot be broken down into simpler substances by a chemical change. The correct option is option A.

To know more about element, here:

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The ground state configuration : 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹

Electrons can move the shell up or down by releasing energy or absorbing energy  

It can be concluded that there are 2 conditions:  

Ground-state is the state of electrons filling the shell with the lowest energy levels.  

Excited-state is the state of electrons which occupies a higher energy level  

The state of excited electrons can be seen from the presence of electrons which do not fill the shell completely but fill the shell afterward  

Gallium (Ga) is a metal located in group 13, p-block and  period 4

Atomic number : 31

If we look at the options:

options 1,2 and 3 do not conform to Aufbau principle(Electrons occupy orbitals of the lowest energy level  ), because 3d orbitals do not exist and the number of electrons is also not 31

So that the most appropriate electron configuration is:

1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹ = 31 electrons

or we can write : [Ar] 4s² 3d¹⁰ 4p¹

Answer:

C: amount of mass in a certain volume

Explanation:

Just took the quiz and got 100%

Answer:

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question

density = 2 g/ml

volume = final volume of water - initial volume of water

volume = 508 - 500 = 8 mL

We have

mass = 2 × 8

We have the final answer as

Hope this helps you

Answer:

The rock on the right is foliated

Explanation:

I took the test

Answer:

Iodine

Explanation:

I hope this answer will help you

Answer:

silicon. ?

Explanation:

lmk if its right.

Answer

Calculating the mass number for an atom requires that we know the atomic number and the number of protons in the atom’s nucleus. The mass number then gives us the average weight of atoms of a given element. However, as long as the number of protons equals the number of neutrons, the values balance out and we always obtain a whole number for the mass number.

Explanation:

those 3

Answer:

it is 75 degrees

Explanation:

Volume is 138.7 mL.

The equation for calculation of volume is as follows:-

[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]

STP:-

Temperature=273 K

Pressure=1 atm

[tex]\frac{1 atm\times250mL}{273 K} =\frac{2 atm\times V_2}{303\ K}\\V_2=138.7\ mL[/tex]

Hence, the volume is 138.7 mL.

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Answer: Two hydrogen atoms

Explanation:

A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.

Answer:

The statement which describes an intensive property of matter is - :

it is the same for every sample of a single substance.

Explanation:

Hence , the correct option is A (it is the same for every sample of a single substance).

Answer: With a positively charged nucleus.

Explanation:

Answer:

Chlorofluorocarbons and hydrochlorofluorocarbons are fully or partly halogenated paraffin hydrocarbons that contain only carbon, hydrogen, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon.

Explanation:

Answer:

Explanation: Chlorofluorocarbons and hydrochlorofluorocarbons are fully or partly halogenated paraffin hydrocarbons that contain only carbon, hydrogen, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon

Answer:

Mass of Cr= 78 g

Explanation:

Given data:

Specific heat of Cr = 0.448 j/g.°C

Initial  temperature of Cr lump = 89.5°C

Mass of water = 75.2 mL or 75.2 g

Initial temperature of water = 20.5°C

Final temperature of water = 27.4°C

Mass of Cr = ?

Solution:

when we placed the lump of Cr metal into water heat lost by limp is equal to the heat gain by water.

Specific heat capacity of water is 4.184 j/g.°C

Q = mcΔT

Q = 75.2 g× 4.184 j/g.°C × (27.4°C - 20.5°C)

Q = 2171 J

Heat lost by Cr lump is -2171 J. Now we will calculate the mass of Cr.

Q = mcΔT

-2171 J = m ×0.448 j/g.°C × ( 27.4°C- 89.5°C)

-2171 J = m × -27.821 j/g

m = -2171 J/-27.821 j/g

m = 78 g

Answer:

Radio is used primarily for communications including voice, data and entertainment media.

Answer:

Mass of CsXeF₇  = 99.3 g

Explanation:

Given data:

Mass of CsF = 37.8 g

Mass of CsXeF₇ produced = ?

Solution:

Balance chemical equation:

CsF + XeF₆   →    CsXeF₇

Number of moles of CsF:

Number of moles = mass/molar mass

Number of moles = 37.8 g/ 152 g/mol

Number of moles = 0.25 mol

Now we will compare the moles of CsF with CsXeF₇  from balance chemical equation:      

                   CsF             :         CsXeF₇

                    1                 :             1

                 0.25             :           0.25

Mass of CsXeF₇ :

Mass = number of moles × molar mass

Number of moles = 0.25 mol × 397.2 g/mol

Mass = 99.3 g

Answer:

98.84

Explanation:

Answer: Here are some examples

Explanation:

1. In the southern spring, ozone is destroyed above Antarctica, mainly by manufactured compounds called chlorofluorocarbons (CFCs )

2. It is now generally accepted that the loss of stratospheric ozone is caused by chemical reactions initiated by chlorofluorocarbons.

3. Your refrigerator and other home appliances emit Chlorofluorocarbons, or CFCs, as do aerosol spray cans.

Hope this hlps!

Explanation:

To be able to put the chemical term chlorofluorocarbons in a sentence, you must first understand what the chemical species denotes.

We know chlorofluorocarbons are a group of compounds that consists of atoms of chlorine, flourine, and carbon.

Now, here are some sample sentences;