What are the most important topics for revision in chemistry?​

Answers

Answer 1

Answer:

structure of atom

states of matter

classification of elements and periodicity in properties

thermody namic

Equilibrium

Redox reacation


Related Questions

Between what two elements does hydrogen bonding occur?

Answers

Answer:

it can occur between hydrogen and 3 other elements

Explanation:

These elements are:

Nitrogen

Oxygen

Flourine

The angle formed by the nuclei of two surrounding atoms with the nucleus of the central atom in a structure is called a(n) ________angle. The value predicted for such an angle using the VSEPR theory would be 180 degrees, based upon geometry alone. This is referred to as the___________ bond angle. In practice, this value often deviates from the predicted value for various reasons.

Answers

The bond angle obtained based on the geometry of the molecule alone is known as the predicted bond angle.

When a compound is formed, the less electronegative atom in the compound is called the central atom in the molecule. The angle formed by the nuclei of two surrounding atoms with the nucleus of the central atom in a structure is called a bond angle.

The bond angle is usually based on the geometry of the molecule. The expected geometry can be deviated for certain reasons such as the presence of lone pairs on the central atom in the molecule. The bond angle obtained based on the geometry of the molecule alone is known as the predicted bond angle.

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Someone please help, I will give brainliest, I am desperate. NO LINKS!!!

Answers

Answer: A. 8.8%

Explanation:

Percent Error Formula: approximate error - actual value divided by actual value (Approximate-Actual/Actual). After those steps are completed, multiply by 100 to make it a percentage form.

0.365 - 0.400 = -0.035

-0.035 / 0.400 = 0.0875

0.0875 * 100 = 8.75%

8.75% rounded to the nearest tenth is 8.8%

A student wants to test for the concentration of food dye FD&C Yellow #5 (Tartrazine) in a yellow Starburst candy. First, the student must prepare standard solutions for the calibration curve. The student has a stock solution of FD&C Yellow #5; the concentration is 0.1140 M. The student takes 6.50mL of the stock solution and dispenses it into a 50.0mL volumetric flask. The flask is then diluted to volume with water. What is the concentration of this standard solution?

Answers

The molarity of the diluted standard solution is obtained by calculation to be 0.015 M.

Recall the dilution formula;

C1V1 = C2V2

C1 = Initial concentration = 0.1140 M

V1 = initial volume =  6.50mL

C2 = Final concentration = ?

V2 = Final volume = 50.0mL

Making C2 the subject of the formula and substituting values;

C2 = C1V1/V2

C2 = 0.1140 M ×  6.50mL/50.0mL

C2 = 0.015 M

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What is the total amount of work done when Danny lifted 25 pounds of weight over 5 meters and applying 30- Newtons of Force? ​

Answers

Answer:

Definition and Mathematics of Work

Calculating the Amount of Work Done by Forces

Potential Energy

Kinetic Energy

Mechanical Energy

BEBE
It is believed the major reason for the decline in amphibian species is
a. death through disease
b. changing reproductive habits
mutation
d. climate change
C.
Please select the best answer from the choices provided


Answers

Answer:

Climate change is the answer

Explanation:

They have to adapt and if the climate changes they no longer can

Answer:

climate change

Explanation:

edge 2022

What is the frequency of the above wave?

Answers

Answer: is a measurement of how often a recurring event such as a wave occurs in a measured amount of time

Explanation:

Which description of salt is a physical property?

Answers

Answer:

White being the color and coming in small grains.

Explanation:

Physical properties are something you can clearly see about the object.

Answer:

Hey mate......

Explanation:

This is ur answer....

It was in the lesson, the answer is it is solid and does not conduct electricity.

 

Physical Properties                                 Chemical Properties

White cubic crystals                                 Do not undergo combustion

Odorless, salty taste                                 Make ionic bonds easily

As solids, they do not conduct electricity  The product of mixing acids and bases.

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Nylon is a synthetic material that has many uses. It is used in the production of machine parts, cookware, and fabric. Nylon is made from petroleum and natural gas. Suppose that there were a shortage of petroleum and natural gas. What would companies that produce nylon likely need to do? A. identify a different natural resource that nylon could be made from B. search for nylon in many different parts of the earth C. convert existing nylon back into petroleum and natural gas D. find a way to make nylon without using natural resources

Answers

In case of a shortage in petroleum and natural gas, a company should find a way to make nylon without using natural resources.

Nylon is a very important material used in numerous applications. As a result of this, the demand for nylon as a raw material has genuinely been on the high side ever since.

However, nylon production depends on petroleum and natural gas. It is possible that there could be a shortage of these resources since they are obtained from the environment. In such cases, a company should  find a way to make nylon without using natural resources.

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Answer:

identify a different natural resource that nylon could be made from

Explanation:

I just did this question

Why are polyatomic called radicals

Answers

that’s because when a charged chemical species composes of two or more atoms (covalently bonded), they act as a single unit. the term radicals refers to free radicals that are with an unpaired electron and because not all of its electrons are found in pairs

The percent of attacks on the dark-colored mouse models is how many times greater than the percent of attacks on light-colored models

Answers

The number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse is four (4) times.

Let the percent of attacks on the dark-colored mouse be D.Let the percent of attacks on light-colored mouse be L.

Given the following data:

Light-colored mouse models = 20 percentDark-colored mouse models = 80 percent

To determine the number of times the percentage of attacks on the dark-colored mouse is greater than the percentage of attacks on light-colored mouse.

Therefore, we would simply divide the percentage for the dark-colored mouse by the percentage for the light-colored mouse as follows:

[tex]Number \;of\;times = \frac{D}{L}[/tex]

Substituting the given parameters into the formula, we have;

[tex]Number \;of\;times = \frac{80}{20}[/tex]

Number of times = 4 times.

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Liquid water can be separated into hydrogen gas and oxygen gas through electrolysis. 1 mole of hydrogen gas and 0.5 moles of oxygen gas is produced from 1 mole of liquid water collected in separate 10 L containers at 1 atm. Will the temperatures of the gases be equal? In one to two sentences, use the ideal gas law to explain your answer. (20 points)

Answers

Answer:

The ideal gas law specifies the mechanical behavior of ideal gases. It is capable of calculating the volume of gases produced or consumed.

In chemical equations, these equations are widely used to convert between volumes and molar quantities.

Use ideal gas law

Therefore

is the same for both So, = same for both.

When n increases, T decreases, so, n is 1 for and 0.5 for , implying that is hotter.

The temperatures of the gases will not be equal.

The ideal gas law specifies the mechanical behavior of ideal gases. It is capable of calculating the volume of gases produced or consumed. In chemical equations, this equation is widely used to convert between volumes and molar quantities. The ideal gas law states that the pressure, temperature, and volume of gas are related to each other

[tex]PV=nRT[/tex]

∵V is the same for both

∴T= same for both.

When n increases, T decreases, so, n is 1 for hydrogen gas and 0.5 for  oxygen gas ,implying that oxygen gas will have more temperature than hydrogen gas since its number of moles are lower than hydrogen gas.

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Under what conditions do you expect hydrogen gas to deviate from ideal gas behavior? Explain your answer.

Answers

Hydrogen is a non-polar gas with very weak intermolecular forces of attraction. Hydrogen will deviate from the ideal gas behavior at high pressure.

is seafloor spreading is beneficial or harmful for the earth

Answers

Answer:

Yes

Explanation

I learned it in science class

wsphorus-SL 3. In the isotope B-11, what does the 11 represent?​

Answers

Answer:

Here boron-11 means the name of the element is boron and the mass number is 11

Explanation:

4. Pb + FeSO4 → PbSO4 + Fe
what type of reaction?​

Answers

Oxidation- Reduction reaction

Which gas makes your voice deeper or has the opposite effect on you than helium when you inhale it.

Answers

The correct answer is Sulfur Hexafluoride
it’s an inert gas that is known to be six times heavier than the air we breathe. While Helium being lighter makes our voice higher, SF6 makes our voice deeper. The sound travels slower in denser gases which is why our voice will come out deeper and rather slow.

Answer:

Sulfur hexafluoride

Explanation:

It is heavier than air that we breathe so it has an opposite effect.

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Order the following elements according to the valence numbers from lowest to highest


1. Boron

2. Sodium

3. Chlorine

4. Beryllium

Answers

Sodium I hope this helps

has anyone done 4.3.4 Practice: Mixtures of Matter...I need help :/

Answers

The types of mixtures are homogeneous and heterogeneous, you can identify these based on their features.

A mixture occurs when two or more materials are mixed or combined. For example, if you combine two or more liquids. Moreover, this can lead to two types of mixtures:

Homogenous mixtures.Heterogeneous mixture.

Each of these has defined features that affect the characteristics and properties of a mixture:

Homogenous mixtures:

Once the mixture is done its components cannot be easily identified.The composition is uniform.Some examples include lemonade, smoothy, and concrete.

Heterogeneous mixture:

The components can be easily identified and even separated after the mixture.The composition is not uniform.Some examples include salad, pizza and oil mixed with water.

Note: This question is incomplete because of this, I answered based on general knowledge.

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Enter the correct ground-state (or lowest energy) configuration based on the number of electrons: 1s^4 2s^4 2p^12.
Express your answer in complete form in the order of orbital filling as a string without blank space between orbitals.

Answers

Answer:

The ground state configuration is the lowest energy, most stable arrangement. An excited state configuration is a higher energy arrangement (it requires energy input to create an excited state). Valence electrons are the electrons utilised for bonding.

or the

FIGURE 5.9 The arrow shows a second way of remembering the order in which sublevels fill. Table 5.2 shows the electron configurations of the elements with atomic numbers 1 through 18.

Element Atomic number Electron configuration

sulfur 16 1s22s22p63s23p4

chlorine 17 1s22s22p63s23p5

argon 18 1s22s22p63s23p6

or the

Two electrons

Two electrons fill the 1s orbital, and the third electron then fills the 2s orbital. Its electron configuration is 1s22s1.

Explanation:

Choose your answer

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Please help
How do we read chemical formulas?

Answers

Answer:

Download Science All formulas

Explanation:

Hope it helps

What happens during
conduction?
A. The warmer object's particles slows
down the cooler object's particles.
B. The warmer object's particles stops the
cooler object's particles.
C. The warmer object's particles speed up
the cooler object's particles.

Answers

Answer:  the answer is C. The warmer object's particles speed up

the cooler object's particles.

Explanation:    Conduction occurs when a substance is heated, particles will gain more energy, and vibrate more. These molecules then bump into nearby particles and transfer some of their energy to them. This then continues and passes the energy from the hot end down to the colder end of the substance.

Which of the following methods will usually cause a reaction to speed up?



Group of answer choices

Removing the catalyst.

Combining the reactants at a lower temperature.

Grinding one of the reactants into a powder.

Reducing the concentration of reactants.

Answers

reducing the concentration of reactants

the method that will usually cause a reaction to speed up from the list given is: Reducing the concentration of reactants.

Meaning of Reaction

Reaction can be defined as the combination of substances or a process where substances acts on each other, where substances changes into different substances.

A reaction can be said to be the event that causes a restructuring or rearrangement of atoms of a substance when it is in contact with another substance.

In conclusion, the method that will usually cause a reaction to speed up from the list given is Reducing the concentration of reactants.

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Sodium carbonate (Na2CO3) reacts with acetic acid (CH3COOH) to form sodium acetate (NaCH3COO), carbon dioxide (CO2), and water (H2O). A chemist carries out this reaction in a bomb calorimeter. The reaction causes the temperature of a bomb calorimeter to decrease by 0. 985 K. The calorimeter has a mass of 1. 500 kg and a specific heat of 2. 52 J/g•K. What is the heat of reaction for this system? kJ.

Answers

Explanation:

Mass of bomb calorimeter, m = 1.5 kg = 1500 g

Temperature change of calorimeter, ΔT = - 0.985 K

Specific heat of calorimeter, c = 2.52 J/g K

To Find:

The heat of reaction for this system

Calculation:

The heat of reaction can be calculated by the given formula:

Q = mcΔT

⇒ Q = 1500 × 2.52 × (- 0.985)

⇒ Q = - 3723.3 J       (-ve sign shows heat is given by calorimeter)

- So the heat of reaction is -3723.3 J or -3.7233 kJ

Taking into account the definition of calorimetry, the heat of reaction for the system is  -3,723.3 J or -3.7233 kJ.

In first place, calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

In this way, between heat and temperature there is a direct proportional relationship.

The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat by the mass of the body.

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Q= ? c= 2.52 [tex]\frac{J}{gK}[/tex] m= 1.500 Kg= 1500 g ΔT= -0.985 K is negative because the temperature decreases.

Replacing in the expression to calculate heat exchanges:

Q= 2.52[tex]\frac{J}{gK}[/tex]× 1500 g× (-0.985 K)

Solving:

Q= -3,723.3 J= -3.7233 kJ

Negative sign shows heat is given by calorimeter.

In summary, the heat of reaction for the system is  -3,723.3 J or -3.7233 kJ.

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Which of the following is true for a nuclear reaction?
O Electrons are lost
Electrons are gained
O Identity of element changes
Oldentity of element remains same

Answers

Identity of element changes.

True statement for a nuclear reactions is that it changes the identity of the element.

What are nuclear reactions?

Nuclear reactions are those reactions in which changes in the nucleus of atoms take place in the form of fission and fussion.

As it is said that changes are taking place in nucleus so the electrons are not gained or lost in this reactions.Identity of the element changes as atomic number of element changes due to change in the number of protons.

Hence identity of element changes.

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how do you find a mole (i need an example) i hate chem pls help

Answers

Answer:

I'm pretty sure its just the mass of the sample divided by the molar mass

for example if I had like 7g of carbon and wanted to find the moles, I would divide the mass I have (7g) by the molar mass (the atomic mass value on your periodic table, in this case for carbon it would be 14g)

moles = [tex]\frac{mass}{molarmass} = \frac{7}{14} = 0.5\ moles[/tex]

Hope this helped

Question 24 of 25
How can one tell if a reaction is a redox reaction?
O A. Elements change phases.
O B. A precipitate is formed.
O C. Spectator ions are present.
O D. Electrons are gained and lost.

Answers

Answer:

D. Electrons are gained and lost

Explanation:

When electrons are gain and lost, redox reaction takes place. In redox reaction, reduction and oxidation tales place simultaneously. Therefore, option D is correct.

What is redox reaction ?

Redox reactions include a change in the oxidation state of the substrate. When electrons are lost or the oxidation state increases, it is called oxidation; when they are gained or the oxidation state decreases, it is called reduction.

Redox reactions are those in which there is a change in the oxidation number, with both an increase and a drop in number. The reaction called non-redox if this does not take place.

Oxidation and reduction always occur jointly because any loss of electrons by one substance must be followed by a gain of electrons by another. Therefore, oxidation-reduction processes or simply redox reactions are other names for electron-transfer events.

Thus, option D is correct.

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Based on seismometer data what kind of information can seismologists calculate?


location, quantity, and time of damage created by earthquake


track movements of magma in the Earth's mantle and find out when volcanos will erupt


the distance of the earthquake's epicenter, the location of the epicenter, and when tsunamis will strike coastal areas


time of earthquake, magnitude and velocity, and type of seismic waves

Answers

Answer:

Time of earthquake, magnitude and velocity, and type of seismic waves

Explanation:

Seismometers allow us to detect and measure earthquakes by converting vibrations due to seismic waves into electrical signals, which we can then display as seismograms on a computer screen. Seismologists study earthquakes and can use this data to determine where and how big a particular earthquake is.

What is the mass of 1.25 x [tex]10^{24}[/tex] atoms of nitrogen?

Answers

Answer:

i dont know

Explanation:

trolololololololololololololololol

Is this statement true or false?


A compound is a substance made of two or more elements joined in a chemical reaction.



true


false

Answers

The correct answer is False.

This is false I hope this helps goodbye
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in which court case did the supreme court rule that flag burning was symbolic speech and protected by the first amendment? directions:write the noun made from the word in the paranthesis , then use the noun in a sentence 1.(pave)____________________________2.(ship)_____________________________3.(argue)____________________________4.(archieve)_________________________5.(arrange)________________________6.(entertain)__________________________ Almost half of the US states have enacted so-called Right to Work laws. Explain what these laws are. Use your text and web sources to get a clear understanding of these laws, and whether they are fair to unions and union members. Look at the issue from both the union's point of view and from the point of view of employees who don't want union representation. Make your answer complete for full credit. Katie is writing a print statement but nothing is printing. Which of the following should she check for?A. Make sure the print statement is surrounded by parentheses.B. Make sure the word print is in all capital letters.C. Make sure there is a colon after the print statement.D. Make sure the next line after the print statement is indented. The plan of Santa Costanza stems from it being a(n) __________ before it was a church. Instead of a nave, it has a walkway along the outer edge, known as an ambulatory. whats The definition of rant help needed! conjugate the verbs into present progressive form (-ing) PLS ANS FAST. Name the process of wind erosion in which the loose particles of sand act as a sand paper. Help me solve these questions ? HWDue Tuesday, December 7, 20211. Tracy's is having a 25% off sale. Dana wants to buy a coat that hasan original price of $83. What is the sale price? A sports store donates basketballs and soccer balls to the boys and girls club. The ratio of basket balls to soccer balls is 7:6. The store donates 24 soccer balls. How many basketballs do they donate x^2-2x+3k=0 find k with D>0sorry for the bad example. holding an average-sized dip or chew in the mouth for 30 minutes delivers as much nicotine as smoking how many cigarettes? Which materials are used to make concrete select all that apply They allow us. On our choice of the elective subjects in school and your hobbies. Write a story that ends with the statement:then I realized it was too late to cry Why cant a virus reproduce on its own? Confucius developed a philosophy for life and government based on what two things?HELP PLEASEEEEE what does the tragedy of the commons refer to? What is NOT promised by democracy?