Thanks for the help :) Question attached below:

Answer:

4.748 seconds

Explanation:

second-order is one in which the rate is proportional to the square of the concentration of one reactant. This can be expressed below;

2A----->P

Where

A is the reactant.

P is the product.

The rate can be expressed as

Rate= k[A]^2

Half-life reffers to time required to reduce the concentration of reactant to half of its initial value.

The half life of reaction can be calculated using below formula

Half-life =. 1/(K*I)

Where,

K = Rate constant = 0.54 1/ms

I = Initial concentration = 0.39 m

If we substitute these values we have

Half-life t(1/2) =1/(0.54×0.39)

=4.748 seconds

Therefore, the half life is 4.748 seconds

Answer:

Ksp= 7.98 × 10^-13

Explanation:

According to the question, we are to calculate the solubility constant (Ksp) of Zinc carbonate (ZnCO3) in a dissolved solution.

The equilibrium of the reaction is:

ZnCO3 (aq) ⇌ Zn2+ (aq) + CO32- (aq)

According to this; 1 mole of Zinc carbonate (ZnCO3) dissolves to give 1 mole of Zinc ion (Zn2+) and 1 mole of carbonate ion (CO32-).

This illustrates that:

(Zn2+) = 1.12 x 10-4 g/L

(CO32-) = 1.12 x 10-4 g/L

However, 1.12 x 10-4 g/L is the solubility in mass concentration of ZnCO3, we need to convert it to molar concentration in mol/L by dividing by the relative molar mass of ZnCO3.

To calculate the molar mass of ZnCO3, we say:

Zn (65.4) + C (12) + 03 (16×3)

= 65.4+12+48

= 125.4g/mol.

Hence, molar concentration= 1.12 x 10-4 g/L / 125.4 g/mol

= 8.93 × 10^-7 mol/L.

Therefore;

Zn2+) = 8.93 x 10-7 mol/L

(CO32-) = 8.93 x 10-7 mol/L

Ksp = [Zn2+] [CO32-]

Ksp = (8.93 x 10-7) × (8.93 x 10-7)

Ksp = 7.98 × 10^-13

Answer:

yes, this is an acceptable practice in research.

Explanation:

Note that, having a different result in one's research does not imply it is automatically invalid. However, because there may have been some errors or limitations in the previous work by the male researcher, it is possible that the later results are more accurate, even though she used the same procedures. She may have been more careful when calculating her results.

Answer:

Since the results did not match, she should repeat the investigation again. If the data still cannot be replicated, then the results are not valid. In that case, the next step is to restart the process of inquiry from the beginning. An improved design might produce valid, repeatable results.

Explanation:

Answer:

1200 J/K  

Explanation:

The formula for the entropy associated with a reversible phase change is

[tex]\Delta S= \dfrac{q_{\text{rev}}}{T}[/tex]

1. Calculate q

For a reversible phase change like melting,

[tex]q_{\text{rev}} = m\Delta_{\text{fus}}H = \text{1000 g} \times \dfrac{\text{334 J}}{\text{1 g}} = \text{334 000 J}[/tex]

2. Calculate ΔS

[tex]\Delta S = \dfrac{q_{\text{rev}}}{T} =\dfrac{\text{334 000 J}}{\text{273.15 K}} = \textbf{1200 J/K}[/tex]

Answer:

Krypton.

Explanation:

By Graham's Law:

Rate 1 / Rate 2 = sqrt M2 / sqrt M1

Molecular Mass for Neon  is 20.18

so we have:

38 / 77.5  =  sqrt 20.18 / sqrt x    where x is the unkown gas.

sqrt x = 9.162

x = 83.94.

This gas is Krypton.

A sample of neon effuses from a container in 38 s. The same amount of an unknown noble gas requires 77.5 s. The unknown gas is krypton.

The noble gases are a group of chemical elements that share several characteristics. They are all monatomic, odorless, and colorless gases with relatively little chemical reactivity under normal conditions. Helium, neon, argon, krypton, xenon, and radioactive radon are the six types of noble gases that are found in nature.

Due to their filled valence shells (octets), which render them incredibly nonreactive, the noble gases (Group 18), which are found in the far right of the periodic table, were formerly known as the "inert gases."

Due to their fully filled outer electron shells and lack of propensity to react with other elements, noble gases which are most frequently found as monatomic gases rarely form compounds with other elements.

By Graham's Law ;

Rate 1 ÷ Rate 2 = sqrt M2 ÷ sqrt M1

The Molecular Mass for Neon  is 20.18

Then,

38 ÷ 77.5  =  sqrt 20.18 / sqrt x    

where x is the unknown gas.

sqrt x = 9.162

x = 83.94.

This is Krypton gas.

Thus, The unknown gas is krypton which is noble gas.

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Explanation:

The Absorption of Light by Chlorine, Bromine and their Gaseous Mixtures

Answer:

C. H2O (l) --> H2O (g)

Explanation:

Hello,

In this case, we need to remember that processes absorbing energy are those that have positive heat, it means, process that obtain energy from a certain source. In such a way, processes that need energy, in terms of phase chance are fusion, sublimation and evaporation, which are the change from solid to liquid, solid to gas and liquid to gas respectively. Therefore, for the given options, we can see that C. H2O (l) --> H2O (g) accounts for an evaporation process which actually absorbs energy.

Best regards.

Answer:

A=0.173 Km

B=0.00256 km

C=56.7 m

D=5130 mm

Explanation:

first we need to know that

[tex]1km=1000m\\\\1dm=0.1m\\\\1000mm=1m[/tex]

so we can form the following

[tex]\frac{1km}{1000m}=1\\\\\frac{0.1m}{1dm} \\\\\frac{1000mm}{1m}[/tex]

so in A

[tex]17.3m\\\\=17.3m*1\\\\=17.3m(\frac{1km}{1000m} )\\\\=0.0173km[/tex]

in B

[tex]2.56m\\\\=2.56m*1\\\\=2.56m(\frac{1km}{1000m} )\\\\=0.00256km[/tex]

in C

[tex]567dm\\\\=567dm*1\\\\=567dm(\frac{0.1m}{1dm} )\\\\=56.7m[/tex]

in D

[tex]5.13m\\\\=5.13m*1\\\\=5.13m(\frac{1000mm}{1m} )\\\\=5130mm[/tex]

Answer:

The probability  of spinning red with the spinner or rolling an odd number with the  die is [tex]\dfrac{1}{8}[/tex]

Explanation:

Given that,

Total color in spinner = 4

Let the area of four parts is equal in the spinner.

We need to calculate the probability of spinning red

Using formula of probability

[tex]P(A) = \dfrac{Number\ of\ red\ color\ outcome}{Total\ number\ of\ colors\ in\ the\ spinner}[/tex]

Put the value into the formula

[tex]P(A)=\dfrac{1}{4}[/tex]

We need to calculate the probability of odd number of the die

Using formula of probability

[tex]P(B) = \dfrac{Number\ of\ odd\ digits\ outcome}{Total\ number\ of\ digits\ in\ the\ die}[/tex]

Put the value into the formula

[tex]P(B)=\dfrac{3}{6}[/tex]

[tex]P(B)=\dfrac{1}{2}[/tex]

We need to calculate the probability  of spinning red with the spinner or rolling an odd number with the  die

Using formula of probability of two events which is independent

[tex]P(A\ and\ B)=P(A)\times P(B)[/tex]

Put the value into the formula

[tex]P(A\ and\ B)=\dfrac{1}{4}\times\dfrac{1}{2}[/tex]

[tex]P(A\ and\ B)=\dfrac{1}{8}[/tex]

Hence, The probability  of spinning red with the spinner or rolling an odd number with the  die is [tex]\dfrac{1}{8}[/tex]

Answer: C

Explanation:

Spaghetti and meatballs are Heterogeneous mixture. A heterogeneous mixture is a mixture that is not uniform in composition throughout the mixture.

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Answer:

E. the procedure

Explanation:

In scientific experiments, several steps are taken in order to achieve a significant result. However, the steps involved when performing the experiment should be taken note of and written down in a very comprehensible manner. The written step by step process involved in an experiment is called the PROCEDURE.

A procedure should be a guide to performing the experiment by a new experimenter. It should include everything done during the experiment. In this case, Mrs. Integer is telling Mrs. Apex to write down all she is doing during the experiment in a step by step manner. In essence, the principal is simply asking her to write a PROCEDURE.

Explanation:

ATOMIC THEORY

Lesson 1 - Page 5

J.J. Thomson

In 1897, English physicist J. J. Thomson (1856–1940) disproved Dalton’s idea that atoms are indivisible. When elements were excited by an electrical current, atoms break down into two parts. One of those parts is a negative tiny particle, which Thomson called a corpuscle in 1881. The term electron was introduced in 1891 by G. Johnstone Stoney (1826-1911) as a way to describe a “natural unit of electricity.” Thomson envisioned these negative charges embedded into positive charges, like an English plum pudding. The plums were the electrons and the pudding was the positive matter.

Thomson's idea of an atom did not survive very long. English physicist Ernest Rutherford (1871–1937) studied the effects of bombarding thin gold foil with alpha particles. Alpha particles are helium atoms that have lost their electrons and are positive. Rutherford’s model had a nucleus, which occupied a very small area toward the middle, and was positive. He used the term proton for the positive particles. However, his electrons were moving on the outside of the nucleus in no definable manner in his model.

A is Dalton's Model; B is Thomson;

and C is Ruthford's model of an atom

Answer:

crude oil

Explanation:

The substance X would be crude oil.

Crude oil is a non-renewable natural resource that is black and thick in appearance. It is a mixture of several products and these are often separated by a process known as fractional distillation.

Some of the products from the fractional distillation of crude oil include the premium motor spirit (petrol), automotive gas oil (diesel), kerosene, etc., and derivatives for the production of dyes, paints, perfumes, etc.

Answer:

c

Multiply 3,000 by 3.8 and divide the result obtained by 12

Answer:

B. [tex] 5 \times {10}^{ - 5}\: m [/tex]

Explanation:

[tex]0.00005 \: m= 5 \times {10}^{ - 5} \: m \\ [/tex]

Answer:

i think quantitative observation

Answer:

After three hours, concentration of C₂F₄ is 0.00208M

Explanation:

The rate constant of the reaction:

2 C2F4 → C4F8 is 0.0410M⁻¹s⁻¹

As the units are M⁻¹s⁻¹, this reaction is of second order. The integrated law of a second-order reaction is:

[tex]\frac{1}{[A]} =\frac{1}{[A]_0} +Kt[/tex]

Where [A] and [A]₀ represents initial and final concentrations of the reactant (C₂F₄), K is rate constant (0.0410M⁻¹s⁻¹) and t is time of the reaction (In seconds).

3.00 hours are in seconds:

3 hours ₓ (3600 seconds / 1 hour) = 10800 seconds

Initial concentration of C2F4 is:

0.105mol / 4.00L = 0.02625M

Replacing in the integrated law:

[tex]\frac{1}{[A]_0}= \frac{1}{0.02625} +0.0410M^{-1}s^{-1}*10800s\\\frac{1}{[A]_0}=480.9M^{-1}[/tex]

[A] = 0.00208M

Answer:

Average atomic mass = 63.3896

Explanation:

Step 1: Find how much Cu-65 we have

1 - Amount of Cu-63 = Amount of Cu-65

1 - 0.6915 = Amount of Cu-65

Amount of Cu-65 = 0.305

Step 2: Find the average atomic mass of Cu

(0.6915 x 63) + (0.305 x 65) = Average atomic mass

(43.5645) + (19.825) = Average atomic mass

63.3895 = Average atomic mass

Therefore the average atomic mass of Cu is 63.3895 atomic mass units

Answer:

Alchemy is a practice of making gold from other metals.

Explanation:

Alchemy is a method which is practiced by the ancient scientists of Europe, Africa and Asia trying to produced gold from other metals. This method was failed to produced gold from metals and all scientist suggested that metals can not be converted into gold. Greeks were the people who presented the theory of alchemy in the first few centuries of CE.

Answer:

the answer is Alchemy was scientific because it included observations and experiments

Explanation:

i took the test

Explanation:

First find the mass of 1 mole of water (Molecular mass)

[tex] H_{2} O = 2H + O [/tex]

[tex]

= 2(1) + 32 [/tex]

[tex]

= 34 \: grams

[/tex]

Hence 1 mole of water is 34 g

Compare

1 mole = 34 g

1.33 mole = x g

[tex] \frac{x}{34} = \frac{1.33}{1} [/tex]

[tex]

x = 1.33 \times 34 [/tex]

[tex]

\color{blue}{\boxed{x = 45.2}} \: \: \: \: to \: 3 \: s.f.

[/tex]

Therefore 1.33 moles of water is 45.2 grams

The mass of the substances can be given by the molar mass and the moles of the substances. The mass of 1.33 mole of water is expressed in grams as, 23.94 grams.

The mass has been defined as the product of the moles of the substance and the molar mass in grams per mole. The mass is given in grams and has a formula,

Moles = mass ÷ molar mass

Mass = molar mass × moles

Given,

Moles = 1.33 moles

Molar mass of water (H₂O) is calculated as = 2 (1) + 16= 18 grams per mole

Using the formula of mole, mass is calculated as:

Mass = molar mass × moles

mass = 1.33 × 18

= 23.94 grams

The mass of the substance can be calculated if the value of the molar mass and the moles of the substance has been known. The molar mass of the substance can be calculated by adding the mass of the individual masses of the element in a molecule.

Therefore, 1.33 mol of water contains 23.94 grams.

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Answer:

Todos os três cientistas classificaram os elementos de acordo com o peso atômico.

Explicação:

As características da Tabela Periódica da Tríade Dobereiner são as seguintes:

1. é uma das classificações mais antigas de elementos.

2. nesta classificação, o peso atômico de um átomo é igual à média dos outros dois pesos atômicos.

3. é baseado no peso atômico.

Características do parafuso telúrico de Chancourtois

1. É a primeira classificação baseada no peso atômico.

2. foi a primeira representação gráfica dos elementos da tabela periódica.

Características da Lei das Oitavas de Newlands

1. também organizou os elementos de acordo com o peso atômico.

2. Em uma linha há apenas sete elementos e o oitavo vem abaixo do primeiro elemento devido às mesmas propriedades físicas e químicas.

Answer:

it is A as both are always charged

Explanation:

Answer: A the particle is always charged

Explanation:

Answer:

Explanation:

You can do this by doing dimensional analysis.

The first step is to change grams to mg

1000 mg = 1 gram

So the fraction will look like this

1.03 g * 1000 mg/ 1 gram = 1030 mg (the grams cancel out)

Now move onto the volume. The volume is actually 1 cm^3. This becomes 1 cm^3 / 1000 mm^3

So the answer becomes

1030 mg / cm^3 * ( 1 cm^3/1000 mm^3) The cm^3 cancel out

1030 mg / 1000 mm^3

1.030 mg/ mm^3

Answer:the answer c

Explanation: because he believes that properties of elemets are periodic function of there atomic number

Answer:

No

Explanation:

No, as sometimes objects with large masses are very light since they aren't dense.

Answer:

9.5 inches = 24.1 cm

Explanation:

Given that,

1 inch = 2.54 cm

We need covert 9.5 inches to cm. For this we will use unitary method. To convert 9.5 inches to cm multiply 2.54 and 9.5. So,

9.5 inches = (2.54 × 9.5) cm

9.5 inches = 24.13 cm  

or

9.5 inches = 24.1 cm

Hence, this is the required solution.

Answer:

51096J/mol = Energía de activación para el proceso del canto

Explanation:

Podemos solucionar este problema usando una forma de la ecuación de Arrhenius:

[tex]Ln\frac{K_2}{K_1} = \frac{-Ea}{R} (\frac{1}{T_2} - \frac{1}{T_1} )[/tex]

Donde K representa la velocidad de reacción (En este caso, la velocidad a la que cantan los grillos), Ea es la energía de activación, R la constante de los gases (8.314J/molK) y T representa la temperatura absoluta de 1, el estado inicial y 2, el estado final.

Estado inicial: K1 = 2.0x10²; T1 = 27°C + 273.15 = 300.15K

Estado final: K2 = 39.6; t2 = 5°C + 273.15 = 278.15K

Reemplazando en la ecuación:

[tex]Ln\frac{39.6}{2.0x10^2} = \frac{-Ea}{8.314J/molK} (\frac{1}{278.15K} - \frac{1}{300.15K} )\\\\-1.6195 = \frac{-Ea}{8.314J/molK}*2.6351x10{-4}K{-1}[/tex]

Answer:

Generally, density is measured using he SI unit for measurement of density which is kg/m³ or the cgs units used to describe the density of a substance which is g/cm³

However, due to its nature (being composed of varying amount proportions of different compounds mixed together resulting in a variation of the density of naturally produced crude oil) of having different densities whereby the lighter oils are more easily processed than the heavier variety of oils, oil density is related to the quality of the oil and it is usually measures in API gravity as follows;

°API = (141.5/S.G.) - 131.5

Where;

API = American Petroleum Institute

S. G. = Specific gravity

As such the API gravity of fresh water with a S. G. of 1.0 has is 10 degrees

Explanation:

Answer:

Kinetic energy=1/2mv^2.

1/2×65×2.5^2.

1/2×6.5×6.25.

1/2×40.625.

=20.3125Joules.

The branch of science which deals with the chemicals bond is called chemistry.

The correct answer is 20.3125J

The energy formed by the motion of particles is called kinetic energy. The formula is half of the product of the mass and velocity.

[tex]Kinetic\ energy=\frac{1}{2}mv^2.[/tex]

After putting the value:-

[tex]\frac{1}{2}*65*2.5^2.[/tex]

After solving the equation, the kinetic energy is 20.3125Joules.

Hence, the correct answer is 20.3125Joules.

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