For a first-order reaction, A → B, the rate coefficient was found to be 3.4 × 10-4 s-1 at 23 °C. After 5.0 h, the concentration of A was found to be 0.00018 mol L-1. What was the original concentration of A?

Answers

Answer 1

Answer:

the original concentration of A = 0.0817092  M

Explanation:

A reaction is considered to be of first order it it strictly obeys the graphical equation method.

[tex]k_1 = \dfrac{2.303}{t}log \dfrac{a}{a-x}[/tex]

where;

k = the specific rate coefficient  = 3.4 × 10⁻⁴ s⁻¹

t = time   = 5.0 h = 5.0 × 3600 = 18000 seconds

a = initial concentration = ???

a - x = remaining concentration of initial concentration at time t = 0.00018 mol L⁻¹

[tex]3.4 \times 10^{-4}= \dfrac{2.303}{18000}log \dfrac{a}{0.00018}[/tex]

[tex]3.4 \times 10^{-4}= 1.27944 \times 10^{-4} \times log \dfrac{a}{0.00018}[/tex]

[tex]\dfrac{3.4 \times 10^{-4}}{1.27944 \times 10^{-4}}= log \dfrac{a}{0.00018}[/tex]

[tex]2.657= log \dfrac{a}{0.00018}[/tex]

[tex]10^{2.657}= \dfrac{a}{0.00018}[/tex]

[tex]453.94 = \dfrac{a}{0.00018}[/tex]

[tex]a =453.94 \times 0.00018[/tex]

a = 0.0817092  M

Thus , the original concentration of A = 0.0817092  M


Related Questions

using equation of reaction mention 4 methods of preparation of hydrogen​

Answers

Explanation:

1. Displacement of hydrogen from water by using metal

2. Electrolysis of water using the apparatus known as the HOFMAN VOLTAMETER

3. Cracking of petroleum

4. Action of steam on hot coke

The graph compares the kinetic energies of the molecules in four gas samples. Each graph shows a normal distribution, so the average is the center. Which sample is likely to have the lowest temperature? (1 point) A B C D

Answers

Answer:

d

Explanation:

i got it right

Gas A is likely to have the lowest temperature.  Hence, option A is correct.

What are molecules?

The smallest particle of a substance has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.

In a gas, the kinetic energy is directly proportional to the temperature under constant pressure and volume.

As you can see in the problem, the average of A has low kinetic energy. But the average is increasing between B, C and D.

As gas A has the lowest average kinetic energy:

Gas A is likely to have the lowest temperature

Hence, option A is correct.

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Triangle DEF is congruent to TriangleD'EF' by the SSS theorem. Which single rigid transformation is required to map TriangleDEF onto TriangleD'EF'? dilation reflection rotation translation

Answers

Answer:

B. reflection

Explanation:

Rigid transformations are methods involved in changing the dimensions or orientation of a given figure. The methods are; dilation, rotation, translation and reflection.

Reflection is the process in which a given figure is turned or flipped with respect to a point or line of reference.

In the given question,

ΔDEF ≅ ΔD'EF' (Side-Side-Side congruence property)

This implies that ΔDEF was reflected about point E to produce ΔD'EF'. Thus the required rigid transformation is reflection.

Answer:

Is C - Rotation

Explanation:

I have right on my test

)Assertion: Corrosion is a beneficial process for metals. Reason : Galvanising and electroplating of metals prevent corrosion.

Answers

The assertion is definitely wrong. Corrosion actually means decomposing or rusting of metals. So, corrosion is a harmful process for metals. But, your reason is correct. Galvanising, which means deposition of a layer of zinc on iron to prevent from rusting, is a very beneficial process to prevent metals from corrosion. In some cases, electroplating also helps to prevent from corrosion.

Hope it helps
Please mark my answer as BRAINLIEST

This law relates a planet's orbital period and its average distance to the Sun.
The orbits of planets are ellipses with the Sun at one focus.
The speed of a planet varies, such that a planet sweeps out an equal area in equal time frames.

Answers

Answer:

These are Kepler's Laws of Planetary Motion

Explanation:

Answer:

its Keplers third law,

then first law,

then second law

Explanation:

In which particle model are the red and blue particles MOST LIKELY to bump into each other? PLEASE HELP WILL MARK BRAINLIEST!!

Answers

Answer:

441

Explanation:

In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.

What is Particle Model of Matter?

The particle model of matter is a theory that explains how the particles that make up a substance are arranged, and how they move and interact with each other.

The particle model explains the properties of solids, liquids and gases. The particle model can explain changes of state.

Particles of matter have spaces between them. Atoms and molecules have spaces between them. In a gas, there are large spaces between them. In a a liquid they are closer together. In a solid, the particles are packed close enough together they can hardly move.

Therefore, In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.

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Which type of graph is best used to show how a measured quantity changes over time?

Box and whisker plot
Line graph
Circle graph
Histogram

Answers

Line graph; shows relationship between an independent and dependent variable. One example of an independent variable is time.

When N2gas is passed through water at 293k.how many moles of N2 dissolve in 1litre water

Answers

Answer: 7 milimoles of [tex]N_2[/tex] dissolve in 1 litre water.

Explanation:

Given:  [tex]N_2[/tex] gas is passed through water at 293K.

Assumption :[tex]N_2[/tex] exerts a partial pressure of 0.987 bar.

Take : Henry's constant [tex]p_N_2[/tex] = 76.8 Kbar

[tex]K_H=76800[/tex]

To find : Number of moles of  [tex]N_2[/tex] gas dissolve in 1 litre water.

According to Henry's law,

[tex]p_N_2=K_HX_{N_2}[/tex]

[tex]\Rightarrow\ 0.987=76800X_{N_2}[/tex]

[tex]\Rightarrow\ X_{N_2}=\dfrac{0.987}{76800}=0.0000128515625\approx1.29\times10^{-5}[/tex]

moles in 1 liter  of water = [tex]\dfrac{1000}{18}=55.56\ [\text{Molar mass of }H_2O=18\ g][/tex]

Let n= moles of nitrogen

Total moles = 55.56+n

So,

[tex]X_{N_2}=\dfrac{n}{55.56+n}=1.29\times10^{-5}\\\\\Rightarrow\ 55.56\times1.29\times10^{-5}+1.29\times10^5n=n\\\\\Rightarrow\ n- 1.29\times10^5n=0.000714033\\\\\Rightarrow\ 0.999987n=0.000714033\\\\\Rightarrow\ n\approx7\text{ milimoles}[/tex]

Hence, 7 milimoles of [tex]N_2[/tex] dissolve in 1 litre water.

A current is induced in a wire by moving the wire through a magnetic field. Which is one factor that affects the direction of the current?

Answers

Answer:

One factor that affects that affects the direction of the current is the direction of motion of the wire

Explanation:

According to Fleming's right hand rule when a conductive wire which is within a circuit is moved through a magnetic field, due to Faraday's law of electromagnetic induction an electric current is induced in the wire such that the direction of motion of the wire, the direction of the magnetic field and the direction of the electric current are perpendicular to each other such that if the right hand has the thumb middle finger and the index finger held perpendicular to each other

The motion of the wire being in the direction of the wire

The first or index finger points in the direction of the magnetic field

The middle finger points in the direction of the induced electric current

Therefore, the direction of the the current depends on the direction of motion of the wire.

What is a scientific question?
O A. One that everyone agrees on
OB. One that only scientists ask
O c. One that is answered through observation
O D. One that never changes

Answers

Answer:

O c. One that is answered through observation

I used process of elminations so

Explanation:

One that everyone agrees one doesnt mean it's accurate.

Only the one that scientists ask doesnt make sense

One that never changes and One that is answered through observation.... So C

Which is described as the force holding two atoms together? Select one: a. cation b. chemical bond c. formula unit d. lattice

Answers

Answer:

The correct option is;

b.Chemical bond

Explanation:

Chemical bonds are the attractive forces holding the atoms within a compound together. The concept of chemical bonding is fundamental to the explanation of chemical phenomena including reaction mechanism and molecular behavior

There are different chemical bonds such as ionic bonds formed by the attraction of oppositely charged ions, covalent bonds, formed by the sharing of electrons and polar covalent bonds.

What is the change that turns paper into ashes ? Why ? give reasons​

Answers

Answer:

Chemical change

Explanation:

Burning  paper is a chemical change.

Burning (or combustion ) is a high temperature chemical reaction that takes place  between fuel and an oxidant(mostly  oxygen)

Research has proved has taught us that ;

When paper is burned , the  oxygen (from the air) combines with carbon and hydrogen in the paper turning some of it into carbon dioxide and water vapor, which waft away with carbon particulates in the smoke

I hope it helps :)

You arrive home from class to find your roommate complaining of a headache, dizziness, and nausea. Upon further investigation you believe they may have carbon monoxide poisoning. What should be the first step taken?

Answers

Answer:

tempature of the person, check carbon levels in the house or place where the person is.

Explanation:

To change from tens to hundreds, you multply by

Answers

Answer:

10

Explanation:

Example:

10 · 10 = 100

60 · 10 = 600

Answer:

you multiply by 10.

Explanation:

10 - the one is in the thenth place

10 * 10 = 100 - the one is in the hundreth place

20 - the two is in the thenth place

20 * 10 = 200 - the two is in the hundreth place

How do gases responsible for acid rain get into the atmosphere

Answers

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

in terms of bonds what would the molecule C6H12 be classified as

Answers

It has a double C=C bond so that means it's unsaturated, but it can also be a cyclic compound with only simple C-C bonds

Alkene

I did the test

A π bond could be formed from the overlap of which two orbitals? A) two sp² hybrid orbitals B) a 1s and a sp² hybrid orbital C) a sp and a sp² hybrid orbitals D) two unhybridized p orbitals

Answers

Answer:

D) two unhybridized p orbitals

Explanation:

In covalent bond, to form a bond, each of the two participating atoms would put down an  unpaired electron to be used in forming a shared pair of electrons between them.

There are two types of covalent bonds:

A sigma bond [tex]\sigma[/tex]

A pi bond [tex]\pi[/tex]

A sigma bond is formed when a hybrid orbital (sp,sp² and sp³) overlaps with another hybrid orbital or with s- or p- orbital.

A pi bond is formed when a p-orbital overlaps with another parallel p-orbital laterally. This implies that ,a  π bond could be formed from the overlap of two unhybridized p orbitals.

How would you measure the mass and weight of an object?

Answers

Answer:

Weight = mass × earth's gravitational acceleration

Explanation:

Follow the following steps to measure the mass and weight of an object:

Measure the mass of the object using an accurate measuring scale.Multiply the mass of that object with earth's gravitational  acceleration which is approximately 9.8 N/kg

unknown substance is heated from 10 celsius to 25 celsius, what happens at 17 Celsius

Answers

At 17 celsius ❤️

it will start to boil ❤️

#indian❤️

why can't we extract sodium from aqueous solution of sodium chloride ​

Answers

Answer:

As it is an aqueous solution the sodium is dissolved in the water, if you want to extract it use evaporation

Explanation:

In each of the following groups of substances, pick the one that has the given property. Justify your answer. a) highest boiling point: HBr, Kr, Cl2 b) highest freezing point: H2O, NaCl, Hf c) lowest vapor pressure at 25C: Cl2, Br2, I2 d) lowest freezing point: N2, CO, CO2 e) lowest boiling point: CH4, CH3CH3, CH3CH2CH3 f) highest boiling point: HF, HCl, HBr Could someone help me understand fully how to do this?

Answers

Answer:

A) HBr

b) NaCl

c) I2

d) N2

e) CH4

f) HF

Explanation:

a) HBr has the highest boiling point because its molecules are held by intermolecular hydrogen bonding unlike other compounds listed.

b) the freezing point of a substance is the same as its melting point. Ionic substances have the highest melting points. Hence NaCl has a melting (freezing) point of about 801°C

c) vapour pressure depends on molecular mass. The higher the molecular mass the lower the vapour pressure. I2 has the highest relative molecular mass and hence the lowest vapour pressure.

d) The molecule with the lowest molecular mass is expected to have the lowest intermolecular dispersion forces and hence the lowest freezing point.

e) Degree of dispersion forces and boiling point increases with increase in molecular mass. Since CH4 has the lowest molecular mass, it will also possess the lowest boiling point.

e) The magnitude of electro negativity decreases down the group. Hence, fluorine is the most electronegative element among the halogens. Hydrogen bonding results when hydrogen is covalently bonded to an electronegative element. The strength of the hydrogen bonding depends on the electro negativity of the electronegative element.

For hydrogen halides, HF has the highest boiling point since F is the most electronegative halogen and HF possess the greatest degree of hydrogen bonding among the hydrogen halides. Hydrogen bonding leads to increase in boiling point of substances.

The intermolecular forces in the compound have been responsible for the various properties of the compounds.

(a) Highest boiling point:

The hydrogen bonding has resulted from the electrostatic interaction of the H with the more electronegative atom. The strong interaction results in a higher boiling point.

HBr has consisted of the hydrogen bond, thus having the highest boiling point.

(b) Highest freezing point:

The higher hydrogen bonding in the structure results in a high freezing point. The ionic compounds with electrostatic interactions result in a high freezing point.

NaCl has been an ionic compound, thus has been consisted of the highest freezing point.

(c) Lowe vapor pressure:

Vapor pressure has been inversely proportional to the molecular mass. The higher the molecular weight, the lower has been the vapor pressure.

Iodine has the highest molecular weight, thereby has the lowest vapor pressure.

(d) Lowest freezing point:

Based on the molecular weight, the lower the molecular weight, the lower has been the freezing point of the molecule.

The [tex]\rm \bold{CH_4}[/tex] has the lowest molecular weight, thus the lowest freezing point.

(e) Highest boiling point:

The more electronegative atom in the hydrogen bonding, the higher has been the stability and the higher the boiling point.

HF has the highest boiling point as it has H bonded with the most electronegative element.

For more information about the boiling and freezing point, refer to the link:

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In nuclear fusion, small fragments, like atomic nuclei, neutrons, and other particles, form when energy is released. TRUE FALSE

Answers

Answer:

TRUE

Explanation:

It is true because along with energy, nuclear fusion releases other particles as well. This can include neutrons or atomic nuclei. An example of this is when hydrogen isotopes (D + T) fuse together to create helium it also releases a neutron. Thus D+T --> He + n + energy.

Therefore the answer is TRUE.

Julie finds a snail on the sidewalk and wants to know whether or not the snail moves throughout the day. She places a
single mark on the sidewalk next to the snail.
What will Julie use the mark for initially?
determining how fast the snail moves
acting as a standard unit of measure
determining the displacement of the snail
O acting as a reference point for detecting motion

Answers

Acting as a reference point for detecting motion

The single mark placed on the sidewalk by Julie has been acting as the reference point for detecting the motion of the snail. Thus, option D is correct.

The snail has been the shelled animal that has been mostly residing in the resting condition with limited movement. To evaluate the movement of the snail, there has been the consideration of a point that was the starting point from the movement.

The line that has been set across the sidewalk has been acting as the reference, and the distance traveled has been calculated from that point. Thus, option D is correct.

For more information about the reference point, refer to the link:

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what is the scientific name for the layer of gas that surrounds the earth A. hydrosphere B. biosphere C. atmosphere D. lithosphere

Answers

Answer:

hydro

Explanation: hydrogen

Answer:

C. Atmosphere

Explanation:

First, let’s define each answer choice.

Hydrosphere: all of the water on Earth

Biosphere: the global ecosystem where organisms live

Atmosphere: the envelope of gases around the planet

Lithosphere: the outermost part of the Earth( the crust and upper mantle)

The question asks us to find the scientific name for the layer of gas that surrounds the Earth. The best choice is C. Atmosphere.

Which sequence represents the relationship between temperature and volume as explained by the kinetic-molecular
theory?
higher temperature - more kinetic energy - more space between particles - higher volume
higher temperature-less kinetic energy less space between particles - higher volume
higher temperature → more kinetic energy less space between particles > lower volume
higher temperature-less kinetic energy → more space between particles lower volume
3
and wit

Answers

Answer:

A.

Explanation:

Higher temperature - more kinetic energy - more space between particles - higher volume.

Consider the half reaction below.

Which statement best describes what is taking place?

Chlorine is losing electrons and being oxidized. Chlorine is losing electrons and being reduced. Chlorine is gaining electrons and being oxidized. Chlorine is gaining electrons and being reduced.

Answers

Answer:

balancing of charges of both sides

Answer:

A

Explanation:

A...............................

(b) (i)
What is an ion?

(c)
Name two types of ions and state how they are formed
Types of ions:​

Answers

Answer:

an atom or molecule with a net electric charge due to the loss or gain of one or more electrons

Design a voltaic cell using magnesium as one of the electrodes. Magnesium can be represented as either Metal A or Metal B in the above drawing. Use metal chlorides as the solutions in the two chambers. For example, magnesium chloride, (MgCl2) will be in solution in the chamber with the magnesium electrode. Use NaNO3 in the salt bridge. Select another element for the other electrode. Explain why you selected this element. Include information about the activity of the metal you select and the need for a spontaneous reaction. Metal A: Metal B: In the drawing, 1. Label the oxidation compartment: 2. Label the reduction compartment. 3. Label the direction of the flow of electrons. 4. Label the flow of the magnesium ions. 5. Label the flow of your selected element's ions. 6. What is leaving the salt bridge in the anode compartment? 7. What is leaving the salt bridge in the cathode compartment? 8. Write the oxidation and reduction half-reactions. 9. Calculate the chemical potential of your cell. Show all of your work.

Answers

Answer:

Here's what I get  

Explanation:

You haven't shown your drawing, so I will assume that Metal A is the anode and Metal B is the cathode.

I will make a galvanic cell using Mg and Zn as the metals.

I selected Zn because it is common and readily available in the lab.

Zn is lower than Mg in the activity series, so Mg should be able to displace Zn from its salts

The standard reduction potentials are:

                                         E°/V

Zn²⁺ (aq) + 2e⁻ ⇌ Zn(s);  -0.76

Mg²⁺(aq) + 2e⁻ ⇌ Mg(s); -2.38

The Mg half-reaction has the more negative potential, so it will be the oxidation half-reaction.

8 and 9. Oxidation and reduction half-reactions and cell potential

                                                                                   E°/V

Oxidation:  Mg(s) ⇌ Mg²⁺(aq) + 2e⁻ ;                      +2.38

Reduction: Zn²⁺ (aq) + 2e⁻ ⇌ Zn(s);                         -0.76

                   Mg(s) + Zn²⁺ (aq)  ⇌ Mg²⁺(aq) + Zn(s);  +1.62

The cell potential is positive, so the reaction will be spontaneous.

Mg is the anode, so it is Metal A.

Zn is the cathode, so it is Metal B.

1. The Mg|Mg²⁺ half-cell is the oxidation compartment.

2. The Zn²⁺|Zn half-cell is the reduction compartment.

3. The electrons flow from anode to cathode in the external circuit.

4. The Mg²⁺ ions flow from the Mg through the solution to the salt bridge.

5. The Zn²⁺ ions flow from the solution to the Zn.

6. NO₃⁻ ions flow from the salt bridge into the anode compartment to balance the charge of the developing Zn²⁺ ions.

7. Na⁺ ions flow from the salt bridge into the cathode compartment to replace the charge of the depleted Zn²⁺ ions.

 

Given 16.2 grams of substance Y, if the substance absorbs 2722 joules of energy and the specific heat of the substance is 9.22 J/g·°C, what is the final temperature of the substance if the initial was 26 degrees Celsius?

Answers

Answer:

Final temperature (T) = 44.22°C (Approx)

Explanation:

Given:

Mass of Y (m) = 16.2 gram

Energy required (q) = 2722 J

Specific heat of the substance(c) = 9.22 J/g·°C

Change in temperature ΔT = T - 26°C

Find:

Final temperature (T)

Computation:

q = mcΔT

2722 = (16.2)(9.22)(T - 26°C)

18.224 = T - 26°C

T = 26 + 18.224

T = 44.224°C

Final temperature (T) = 44.22°C (Approx)

Which element would have properties most similar to those of
cesium (Cs)?
O A. Rb
B. Ca
C. Sr
D. Ba.

Answers

Answer:

Rb

Explanation:

This is because they are in the same group which means they share similar properties.

The correct answer is rubidium (Rb).

What do rubidium and cesium have in common?

This family consists of the elements lithium, sodium, potassium, rubidium, cesium, and francium (Li, Na, K, Rb, Cs, and Fr, respectively). Group one elements share common characteristics.

What are the physical and chemical properties of caesium?

It is silvery gold, soft, and ductile. It is the most electropositive and most alkaline element.

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