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

How do you break down an element?

Answers

Answer:

elements cannot be break down

Plzzzzz helpppppp meeeee I am dooo confused

Answers

Answer:

I think the person is not move

Explanation:

b/c the net force is zero............. 100 w + 100 E

............... 100+(-100 = 0

Please help.

Why does the temperature change when a powder is dissolved in water?

Answers

Answer:

In order for the powder to dissolve, each powder molecule must separate from the other powder molecules and be surrounded by water molecules. This shift in arrangement either absorbs or releases energy depending on the situation. It is due to the exchange of energy that the temperature of the solution fluctuates.

Explanation:

:)

Someone help me with this asap for 5p points and BRAINLIEST THANK YOU

Answers

Answer:

High trainability allows the owner to train the dog to handle certain things--some dog can be trained as police dogs and can be taught various jobs, so high trainability is very important

When a dog is Viscous, the dog will keep people away from your house, they will be able to keep danger away and because they are viscous they will be able to handle danger.

Loud bark- A loud bark from a dog can help alert other people when there is a intruder, it makes alot of noise so they can attract attention easily.

Quiet Bark- Ideal for pet owners who do not like noise, they bark quietly so they are not a bother to work or anyone doing something.

how do i set up an electron configuration

Answers

Answer:

Electron configuration can be carried out in two steps which can be:

Sublevel notation

Shell notations.

In the sublevel notation, the sequence of filling electrons into the orbitals of the sublevels are guided by some principles:

the maximum number of electrons in the orbital of sublevels are two for s-sublevel, six for p-sublevel, ten for d-sublevel and fourteen for f-sublevel. This indicates that the maximum number of electrons in an orbital is two.

Aufbau's prinicple states that sublevel with lower energies are filled up before those with higher energies.

Pauli exclusion principle states that no two electrons in an atom can have the same set of the four quantum numbers.

Hund's rule states that electrons go into degenerate orbitals singly first before pairing occurs.

Using the shell notation, numbers are used to denote the sum of electrons in all orbitals each energy level.

For an atom of Be:

Sublevel notation for the 4 electrons 1s²2s²

Shell notation 2,2

Other representation is using the electron dot structure.

Is this a male cat or female?

Answers

Explanation:

Lift the kitten's tail. The opening just under the tail is the anus. Below the anus is the genital opening which is round in males and is a vertical slit in females. In kittens of similar size, the distance between the anus and the genital opening is greater in the male than the female.

TW: use of inapropate words*

Answer:

not enough information to tell

Explanation:

One way you can tell this difference is the distance between the cat's genitals (organs seen on the outside of the body) and the anus.  A male will have a much greater distance between the genitals and anus than females, 1/2 inch apart on a male kitten and over 1 inch apart on a male adult cat.  However, if the two are almost adjacent on a kitten or less than 1/2 inch apart on an adult, it’s a female.

I WILL GIVE BRAINLIEST TO THE RIGHT ANSWER

Which of the following substances would have the strongest
intermolecular forces of attraction present? *

A) HF (Hydrogen Fluoride)
B) HCI (Hydrogen Chloride)
C) HBr (Hydrogen Bromide)
D) HI (Hidrogen lodide)

Answers

Answer:

A) HF (Hydrofluoric acid)

Explanation:

dw I gotchu. So first off there are three types of intermolecular forces of attraction: 1) London-Dispersion, 2) Dipole-Dipole, 3) Hydrogen-Bonding Attraction Forces. That is also ranked in increasing strength, with Hydrogen-Bonding Attraction Forces being the strongest. Every molecule has London-Dispersion forces present and all the diatomic molecules listed have dipole moments of a certain debye (or Coloumb-meter) value. Both are irrelevant here so dw about that. Lets look at the strongest attraction: the hydrogen-bonding one. Now, don't get confused bc all of these acids are bonded to H bc hydrogen-bonding attraction forces only occur when H is bonded to N, O, or F. So Process of Elimination, hydrofluoric acid (HF) has the strongest intermolecular forces of attraction.

Note: If you don't know what inter/intra molecular forces of attraction are, ill give u a quick summary. Intermolecular refers to electrostatic attractions between molecules while intramolecular refers to the actual bonds, single, double, or triple, binding the atoms together. Well there you have it, have a great day. :)

silver has an atomic mass of 107.868 amu. silver has two common isotopes. one of the isotopes has a mass of 106.906 amu and a relative abundace of 51.881%. a. what is the % abundance of the other isotope. b. what is the mass if the other isotope.​

Answers

A. The abundance of the 2nd isotope is 48.119%

B. The mass of the 2nd isotope is 108.905 amu

Let the 1st isotope be A

Let the 2nd isotope be B

A. Determination of the abundance of the 2nd isotope

Abundance of isotope A = 51.881%.

Abundance of isotope B =?

Abundance of B = 100 – A

Abundance of B = 100 – 51.881

Abundance of B = 48.119%

B. Determination of the mass of the 2nd isotope

Atomic mass of silver = 107.868 amu.

Mass of 1st isotope (A) = 106.906 amu

Abundance of isotope A (A%) = 51.881%.

Abundance of isotope B (B%) = 48.119%

Mass of 2nd isotope (B) =?

[tex]atomic \: mass = \frac{mass \: of \:A \times \:A\%}{100} + \frac{mass \: of \:B \times \:B\%}{100} \\ \\ 107.868 = \frac{106.906\times \ \: 51.881}{100} + \frac{mass \: of \:B \times \:48.119}{100} \\ \\ 107.868 = \: 55.464 + 0.48119 \times mass \: of \:B \\ \\ collect \: like \: terms \\ \\ 0.48119 \times mass \: of \:B = 107.868 - 55.464 \\ \\ divide \: both \: side \: by \: 0.48119 \\ \\ mass \: of \:B = \frac{107.868 - 55.464 }{0.48119} \\ \\ mass \: of \:B =108.905 \: amu \\ \\ [/tex]

Therefore, the mass of the 2nd isotope is 108.905 amu

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What is a control group?

A group that changes the variable
The group that applies the variable
The group that tests the variable
A test group where the variable is not changed or applied Which of the following objects is transforming electrical energy into energy of motion?

Answers

Answer:

The group that tests the variable.

Explanation:

The group that tests the variable is a control group.

Answer:

C when testing the group put the varible in control

50 POINTS!!!! PLEASE HELP I AM BEGGING!!!!!!
3CH4 and C3H12 have the same number and kind of elements. How are they different?

Answers

3CH4 refers to three molecules of a
compound and C3H12 refers to only one
molecule of a compound.
3CH4 and C3H12 are actually different
molecules though they contain the same
number and types of atoms. Recall that both
of them are hydrocarbons hence they
contain only hydrogen and carbon.
3CH4 refers to three molecules of methane
while C3H12 refers to one molecule of
diphenyl methane. Hence 3CH4 refers to
three molecules of a compound and C3H12
refers to only one molecule of a compound.

What happens to the atoms in food once animals eat them?

they are destroyed
they are used to make the animal grow
they are released as waste

Answers

Answer:

i think

they are used to male the animal grow

Once the animal eats the food, the atoms in food are  used to make the animal grow.

What is an atom?

An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.

The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.

Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.

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Zn + 2HCl —> ZnCl2 + H2
If you have 6.8 moles of zinc chloride produced, how many moles of zinc reacted?

Answers

Answer:

about 4 or 4.8

Explanation:

Write the chemical formulas and names for the following ionic compounds. Cobalt (III) and bromine

Answers

Answer:

CoBr2,CoBr2·6H2O,CoBr2·2H2O

Explanation:

In order for a chemical reaction to take place, a certain amount of _____ must be present.

Answers

Answer:

The answer is energy. Please give me Brainliest!

Explanation:

Raising the concentrations of reactants makes the reaction happen at a faster rate. For a chemical reaction to occur, there must be a certain number of molecules with energies equal to or greater than the activation energy.

A diprotic acid (H2X) titrated with a solution of NaOH for 25 ml of the acid 87.42 ml of a 1.95 M solution of NaOH was required to reach the equivalent point, the concentration of the diprotic acid equals

0.14
6.8
3.4
0.29

Answers

The concentration of the diprotic acid equals 3.4 M

We'll begin by writing the balanced equation for the reaction.

H₂X + 2NaOH —> Na₂X + 2H₂O

From the balanced equation above,

The mole ratio of the acid, H₂X (nA) = 1The mole ratio of the base, NaOH (nB) = 2

From the question given above, the following data were obtained:

Volume of acid, H₂X  (Va) = 25 mLVolume of base, NaOH (Vb) = 87.42 mLMolarity of base, Ca(OH)₂ (Mb) = 1.95 MMolarity of acid, H₂X (Ma) =?

MaVa / MbVb = nA/nB

(Ma × 25) / (1.95 × 87.42) = 1/2

(Ma × 25) / 170.469 = 1/2

Cross multiply

Ma × 25 × 2 = 170.469

Ma × 50 = 170.469

Divide both side by 50

Ma = 170.469 / 50

Ma = 3.4 M

Therefore, the concentration of the acid, H₂X is 3.4 M

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What does an atom's period tell us?
Select one:
a. Number of protons

b. Number of shells

c. Number of valence
electrons

d. Number of electron

Answers

Question;What does an atom's period tell us? Answer:

•A Number of protons

What is the molarity of a solution of 3.0 mol of KCl in 4.0L of water?

Answers

The number of moles of a solute per liter of solution is measured using the unit of concentration known as molarity.

Thus, The approach for resolving molarity issues is quite straightforward. This describes an easy way to figure out how molarity of a solution.

Remembering the units of molarity (M): moles per liter, is the key to calculating molarity. Calculate how many moles of the solute are dissolved in a solution's liter volume to determine its molarity.

The molarity of a solution made by combining 23.7 grams of KMnO4 with 750 mL's worth of water. You must first determine the amount of moles of the solute because this example lacks the liters or moles required to determine molarity.

Thus, The number of moles of a solute per liter of solution is measured using the unit of concentration known as molarity.

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which statement describes how vapor pressure occurs? (1 point)

a) Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert
pressure on the substance.

b) Some molecules of a substance have low enough kinetic energy to melt. These molecules exert pressure on the substance

c) Some molecules of a substance have low enough kinetic energy to vaporize. These molecules exert
pressure on the substance.

d) Some molecules of a substance have high enough kinetic energy to melt. These molecules exert pressure on the substance

Answers

Some molecules in a substance have a high kinetic energy hence they are able to convert into vapor. These molecules exert pressure on the liquid surface.

We know that the molecules that compose matter are in constant random motion. The kinetic energy of all the molecules in the liquid are not the same. The molecules at the surface of the liquid posses more kinetic energy than the molecules below.

Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert  pressure on the substance.

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Answer:

Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert pressure on the substance.

Explanation:

what are three physical properties with constant value​

Answers

Answer: Certain physical constants (e.g., melting point, boiling point, density, refractivity, solubility) can be found in the literature for many compounds, whereas others (e.g., specific rotation) are characteristic of different groups of compounds and are known for almost all of them.

Explanation:

What is the atomic mass, in amu, of this atom?

Answers

Answer:

1) H - hydrogen - 1.100797

2) HE - helium - 4.00260

3) LI - lithum -6.941

Explanation:

On the periodic table the mass of carbon is reported as 12.01 amu. This is the average atomic mass of carbon. No single carbon atom has a mass of 12.01 amu, but in a handful of C atoms the average mass of the carbon atoms is 12.01 amu.

Round off your answer to one decimal place.

Answers

Answer: 10.4

Explanation:

ph is just as follows:

[tex]pH = -log[H_{3}O^{+}][/tex]

So plugging in our concentration we get:

[tex]-log(4.45*10^{-11})=10.35163999...[/tex]

Then rounding to one decimal place takes us to pH = 10.4

4. Initially, 1 mol of oxygen (assumed to be an ideal gas) has temperature 310 K and volume 12 L. We will allow it to expand to volume 19 L. (a) What would be the final temperature if the gas expands adiabatically

Answers

Answer:

490.83 oK

Explanation:

First of all, we better agree on the meaning of the word adiabatically. It means without the loss or gain of heat. So nothing is given up to or taken from the environment.

This also assumes that no change has occurred in the pressure.

T1 = 310 oK

T2 = ?

V1 = 12 L

V2 = 19 L

T1/V1 = T2/V2

310 / 12 = x/19            Multiply both sides by 19

310*19 / 12 = T2         Multiply 310 * 19 on the left.

5890 / 12   = T2         Divide by 12

490.83 = T2

Which statements best describe the functions of nucleic acids and proteins?.

Answers

The statement describing nucleic acid has been that nucleic acid provides the blueprint for the formation of proteins.

Nucleic acid has been the genomic material in the body that performs the function of storage of information. DNA and RNA are nucleic acids.

The proteins are the biomolecules that are composed of amino acid units bound by the polypeptide bond. The information for the correct sequence of binding of protein has resulted from the mRNA codes.

The correct sequence and folding results in the operational protein, that has been able to perform varying functions. The codes for the binding of protein have resulted from the blueprint consisting of nucleic acid.

Thus, nucleic acid performs the function of acting as a blueprint for the formation of proteins.

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Which of the following is a binary compound?

Answers

Answer: A. CaO

Took the test already.

A chemist dilutes a 1. 0 mL sample of 2. 0 M KNO3 by adding water to it. If the concentration of the solution that is obtained is 0. 0080 M, what is its volume? Use M subscript i V subscript i equals M subscript f V subscript f. 125 mL 250 mL 500 mL 2,000 mL.

Answers

Answer:

We know the initial volume of the potassium nitrate solution is 1.0 mL and the initial concentration is 2.0 M, we also know that an unknown volume of water was added to the solution, which diluted our concentration down to a final value of 0.008 M. We are trying to find the final volume.

Here we can use this formula since the initial and final solutions are proportional. Before that let's define our variables.

[tex]M_1 = 2.0 M\\V_1 = \frac{1.0 mL}{1000} = 0.001 L\\M_2 = 0.008 M\\V_2 = \ ?[/tex]

[tex]M_{1}V_{1} =M_2 V_2\\[/tex]

[tex](2.0)(0.001) = (0.008)V_2\\\\\frac{(2.0)(0.001)}{0.008} = V_2\\\\V_2 = 0.25 L \ or \ (0.25 \ * \ 1000) = 250 \ mL[/tex]

Therefore you would have 0.25 L or 250 mL of your final solution.

Which of the following is a correctly balanced equation? A. NaClO3 → NaCl 3O2 B. 2HgO → 2Hg O2 C. 2ZnS O2 → 2ZnO 2SO2 D. 4CO Fe3O4 → 4CO2 Fe E. 2Fe 2Cl2 → 2FeCl3.

Answers

Answer:

yes is the anser

Explanation:

i donyt know how to be wrong

The correctly balanced equation among the options is 2HgO → 2Hg + O2.

BALANCING CHEMICAL EQUATION:

Balancing a chemical equation means ensuring that the number of atoms of each element on both sides of the equation are the same in accordance to the law of conservation of mass.

To balance a chemical equation, we make use of coefficients, which are numbers placed in front of the element or compound in the reaction.

According to this question, the following equation: 2HgO → 2Hg + O2, is correctly balanced because the number of atoms of Hg (2) and O (2) are the same on both sides.

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PC13 ionic or covalent

Answers

Answer:

The bond between Phosphorus and Chlorine in PCl3 is covalent as chlorine needs one electron and phosphorus has metallic character and easily donate electron

NEED HELP ASAP PLZZZ

Answers

Answer:

Im pretty sure the answer is A. An electron moves from the FIFTH energy level down to the SECOND energy level.

Explanation:

explain the concept of thekinetic molecular theory

Answers

Answer:

Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions. Kinetic Molecular Theory can be used to explain both Charles' and Boyle's Laws. The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

Explanation:

hope this helps! goodluck & enjoy the rest of ur day or night.

How do covalent compounds differ from ionic compounds?

Answers

Answer:

1. Ionic bonds result from transfer of electrons, but covalent bonds are formed by sharing.

2. Ions are arranged in a three-dimensional array (like crystals). Covalently bonded substances exist as discrete molecular units.

3. Ionic compounds often dissociate into ions in solution, but covalently bonded molecules retain their molecular identity in solution.

Hope this helps :)

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