Define symbole and valeny.​

Answers

Answer 1

Answer:

Chemical symbol

This is used to identify an element without having to write the full name and as such is a designation for the element. It is used in chemical reactions and is usually either one or two letters. Some symbols are, Iron - Fe, Hydrogen - H and Oxygen - O.

Valency

This refers to the capacity of an element to combine with another to form a compound. It is measured by the number of electrons that an atom of an element gains, looses or shares when a chemical reaction involving it takes place.


Related Questions


14. Which of the following involves a chemical change?
A.mixing
b. melting
grinding
d. decomposing

Answers

Answer:

D. decomposing

General Formulas and Concepts:

Chemistry

Chemical vs Physical Changes

Explanation:

A would be incorrect because mixing 2 things together doesn't necessarily create a chemical change. Take oil and water for example. You can mix the 2 and it would not have a chemical change.

B would be incorrect because you are simplify changing the state of matter of the object. Iron in solid form is still iron in liquid form; there is no chemical change.

C would be incorrect for similar reasons as B. You are simply changing the state of matter.

D would be the remaining and correct answer. Decomposing changes one object into a different one by chemically changing.

Rank the electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest

Answers

Answer:

Potassium < lithium <  Selenium < Oxygen

Explanation:

Oxygen has the highest electronegativity value from the given choices.

Electronegativity of an element is a property that combines the ability of its atom to lose and gain electrons.

It is a measure of the relative tendency with which atoms of the element attracts valence electrons in a chemical bond.

Down a group, electronegativity reduces and across the period from left to right, it increases

Potassium and lithium are in group 1 , selenium and oxygen are group 7;

 So group 1 elements will have lower electronegativity value.

Potassium is below lithium in group 1 and its electronegativity value will be lower.

Selenium is below oxygen and also, its electronegativity value is lesser.

The electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest is potassium, lithium, selenium and oxygen.  

The electronegativity of an element is a measure of the tendency of an atom of element to attract bonding pair of electrons. Electronegative elements have the ability to attract shared electrons of covalent bonds to itself.

The most electronegative element is fluorine. Electronegativity increases across the period in the periodic table .

Electronegativity decreases down the group in the periodic table. Generally metallic elements are have lower electronegativity. This is because they mostly give out there electrons.

Therefore,  the electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest is potassium, lithium, selenium and oxygen.  

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What mass of zinc will completely react with 18.9 L of oxygen gas at 15°C and 1.50 atm pressure to produce zinc oxide. Remember to write a balanced. equation and fill in what is needed to answer this question on the BCA table.

Answers

Answer:

Mass of zinc react with oxygen = 156.91 g

Explanation:

Given data:

Volume of oxygen = 18.9 L

Temperature = 15°C

Pressure = 1.50 atm

Mass of zinc react with oxygen = ?

Solution:

Chemical equation:

2Zn + O₂     →       2ZnO

Number of moles of oxygen:

PV = nRT

1.50atm ×18.9 L = n× 0.0821 atm.L / mol.K × 288 K

28.35 atm.L =  n× 23.64atm.L / mol

n = 28.35 atm.L  / 23.64atm.L / mol

n = 1.2 mol

Now we will compare the moles of oxygen and Zn.

             O₂          :           Zn

               1            :            2

              1.2          :        2/1×1.2 = 2.4 mol

Mass of zinc required:

Mass = number of moles × molar mass

Mass = 2.4 mol × 65.38 g/mol

Mass = 156.91 g

(04.03 LC)
Which of the following is used up during cellular respiration?
O Carbon dioxide
O Mitochondria
O Oxygen
O Water

Answers

Answer:

Oxygen

Explanation:

Cellular respiration is the metabolic process that involves the breakdown of glucose molecule in order to synthesize energy in form of ATP. However, this cellular respiration can either be aerobic or anaerobic depending on whether oxygen is used or not.

Aerobic cellular respiration is the respiration that involves the use of OXYGEN. It occurs in the mitochondria of the cell, where oxygen is used as the final electron acceptor. Hence, according to the question, OXYGEN is used up during cellular respiration.

Answer:

Oxygen

Explanation:

got it on the test(:

What would you see if you were standing on the Earth's surface in the penumbra and you were looking up at the sky?

Answers

Answer:

clouds?

Explanation:

im sorry i just wanted the 23 points

3. Write the equation for the reaction of metal with oxygen and non metal with oxygen and then
predict the nature of the substance formed when the oxide of metal and oxide of non metal is
dissolved in water.​

Answers

Answer:

Acidic Oxides: Acidic oxide are oxides that react with water to form an acid. Acidic oxides are formed by reaction of non metals with oxygen .

[tex]S+O_2\rightarrow SO_2[/tex]

[tex]SO_2+H_2O\rightarrow H_2SO_4[/tex]

Basic Oxides: Basic oxides are oxides that react with water to form bases. Basic oxides are formed by reaction of metals with oxygen.

[tex]2Mg+O_2\rightarrow 2MgO[/tex]

[tex]MgO+H_2O\rightarrow Mg(OH)_2[/tex]

What is the molecular formula of a substance whose molar mass is 166.8 grams and its empirical formula is C2H4N2?

Answers

Answer:

C4H2O6

Explanation:

HELP
1) A 400g sample of alcohol (c = 2.43 J/g°C) at 16°C is mixed with 400g
of water (c = 4.19 J/g°C) at 85°C. What is the final temperature of the
mixture?

Answers

Answer:

Explanation:

Given data:

Mass of alcohol = 400 g

Specific heat capacity of alcohol = 2.43 J/g°C

Initial temperature of alcohol = 16°C

Mass of water = 400 g

Specific heat capacity of water = 4.19 J/g°C

Initial temperature of water = 85°C

Final temperature of mixture = ?

Solution:

Equation:

m₁c₁ (T₂-T₁ ) = m₂c₂(T₂-T₁)

by putting values,

400 × 4.19  × (T₂ -  85°C) = 400 × 2.43  × (T₂ - 16°C)

1676  × (T₂ -  85°C) = 972 × (T₂ - 16°C)

How many atoms are in a sample containing 7 moles of phosphorus?

Answers

1. d.4.125 x 10²⁴ atoms

2. c. 487.73 g

Further explanation  

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

1. 7 moles of phosphorus, so n=7, then number of atoms :

[tex]\tt N=7\times 6.02\times 10^{23}\\\\N=4.215\times 10^{24}[/tex]

2. 2.5 moles of Pt, so n=2.5, the mass of Pt(MW=195,084 g/mol) :

[tex]\tt mass=mol\times MW\\\\mass=2.5\times 195,084\\\\mass=487.73~g[/tex]

The function of a specific enzyme is mostly determined by its

Answers

Answer:

What does the shape of an enzyme determine? The shape of the enzyme determines which chemical reaction it will speed up. -The region on an enzyme that the substrate fits into. ... The active site of an enzyme only fits one type of substrate molecule.

Explanation:

The pressure on a 200-milliliter sample of CO2(g) at constant temperature is increased from 60 kPa to 120 kPa. What is the new volume of the gas?

Answers

Answer:

100 milliliter

Explanation:

Initial Pressure P1 = 60 kPa

Final Pressure P2 =   120 kPa

Initial Volume V1 = 200mL

Final Volume V2 = ?

These parameters are related by the following boyle's law which is mathematically given as;

V1P1 = V2P2

Making V2 subject of interest;

V2 = V1P1  / P2

inserting the values;

V2 = 200 * 60  /  120

V2 = 100ml

How many moles of sulfur trioxide are formed from 3 moles of oxygen using the given
balanced equation?
2 SO. +0,- 2 so.

Answers

Answer:

6 moles of SO₃ formed.

Explanation:

Given data:

Number of moles of SO₃ formed = ?

Number of moles of oxygen react = 3 mol

Solution:

Chemical equation;

2SO₂+ O₂      →   2SO₃

now we will compare the moles of oxygen and sulfur trioxide.

                             O₂            :            SO₃

                               1             :             2

                               3            :           2/1×3 = 6 moles

Thus, six moles of SO₃ will formed.

guys please help me i really need help! pls and thank you!​

Answers

Answer:

Hydrogen

Explanation:

2. Which of the following is a greenhouse gas?​

Answers

Water vapor, carbon dioxide, methane, nitrous oxide, ozone

What's the balanced equation for Iron and copper (II) sulfate solution.

Answers

Answer:

 2Fe +  3CuSO₄  →  Fe₂(SO₄)₃   +  3Cu

Explanation:

The reactants are:

   Iron  = Fe

  Copper (II) sulfate solution = CuSO₄

The reaction is given as:

            Fe +  CuSO₄  →  Fe₂(SO₄)₃   +  Cu

This is a single displacement reaction;

  Now let us balance the equation;

             aFe +  bCuSO₄  →  cFe₂(SO₄)₃   +  dCu

Conserving Fe;

                       a  = 2c

  Conserving  Cu;

                      b  = d

  Conserving S;

                      b  = 3c

  Conserving O;

                    4b  = 12c  

let b  = 1;

    c = [tex]\frac{1}{3}[/tex]  

     d  = 1

     a  = [tex]\frac{2}{3}[/tex]

Multiply through by 3 to get whole numbers;

  a  = 2, b = 3, c  = 1 and d  = 3

           2Fe +  3CuSO₄  →  Fe₂(SO₄)₃   +  3Cu

           

The formation of an ionic compound involves the transfer of electrons. The removal of one or more electrons from a metal is a process that _____ energy, whereas the addition of one or more electrons to a nonmetal _____ energy.

Answers

Answer:

Absorbs, Releases

Explanation:

The formation of an ionic compound involves the transfer of electrons. The removal of one or more electrons from a metal is a process that absorbs energy, whereas the addition of one or more electrons to a nonmetal releases energy.

Answer:

Absorbs

Release

Explanation:

The formation of ionic compounds occurs between two kinds of atoms having a large electronegativity difference (Δx ≥ 0.7) e.g metals (like those in group IA and IIA) and non-metals(like those in groups VIA and VIIA). The formation of an ionic bond involves the transfer of electron(s) from the less electronegative atom (metal) to the more electronegative atom (non-metal) such that the two kinds of atoms now have a completely filled outer shell like the noble gas.

Can someone help me on this? (The second one has the same options as the first one)

Answers

Answer:

EASY ITS BUILT DIFERENT

Explanation:

If the half-life of substance A is 1.5 years, how long would it take an 8.0 gram sample of stances A to decay such that only 1.0 gram remained?

Answers

Answer: 4.5 Years

Explanation:

8 -> 4 -> 2 -> 1

Substance goes through 3 Half-Lives

3 Half-Lives x 1.5 Years = 4.5 Years

Answer:

4.5 i think

Explanation:

Which square (A, B, C, or D) represents the repeating subunit of the polymer shown?

Answers

Where is the picture?

Answer:

c is the answer

Explanation: just answerd it and got it correct

HELP pleaseee its due soon

Answers

Om sister

6 C

7 A

8 C

9 D

10 B

Please help me answer this first question.

Answers

Answer:

I think it would be 9 moles.

Na2S2O3 + AgBr NaBr + Na3ſAg(S203)2] What is
the mass of NaBr that will be produced from 42.7 g of AgBr?

Answers

Answer:

Mass of NaBr produced  = 23.67 g

Explanation:

Given data:

Mass of AgBr = 42.7 g

Mass of NaBr produced = ?

Solution:

Chemical equation:

2Na₂S₂O₃ + AgBr    →    NaBr + Na₃(Ag(S₂O₃)₂

Number of moles of AgBr:

Number of moles = mass/molar mass

Number of moles = 42.7 g/ 187.7 g/mol

Number of moles = 0.23 mol

now we will compare the moles of AgBr with NaBr.

             AgBr        :         NaBr

                1            :           1

              0.23       :         0.23

Mass of NaBr:

Mass = number of moles × molar mass

Mass = 0.23 mol × 102.89 g/mol

Mass = 23.67 g

Which type of reaction occurs in the core of a nuclear reactor in a nuclear power plant? Upper H upper C l plus upper N a upper O upper H right arrow upper H subscript 2 upper O plus upper n a upper C l. Superscript 235 subscript 92 upper U plus superscript 1 subscript 0 n right arrow superscript 90 subscript 38 upper S r plus superscript 143 subscript 54 upper X e plus 3 superscript 1 subscript 0 n. Superscript 90 subscript 38 upper S r plus superscript 143 subscript 54 upper X e plus 3 superscript 1 subscript 0 n right arrow superscript 235 subscript 92 upper U plus superscript 1 subscript 0 n. Upper C subscript 10 upper h subscript 8 plus 12 upper O subscript 2 right arrow 10 upper C upper O subscript 2 plus 4 upper H subscript 2 upper O.

Answers

Answer:

Superscript 235 subscript 92 upper U plus superscript 1 subscript 0 n right arrow superscript 90 subscript 38 upper S r plus superscript 143 subscript 54 upper X e plus 3 superscript 1 subscript 0 n.

Explanation:

B

Answer:

b

Explanation:

got it right on test

what is the name of this molecule?
a. Ethanal
b. Ethylamine
c. Ethanoic acid
d. Ethanol

Answers

The answer would be B Ethylamine

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the correct option is option B that is Ethylamine.

What is chemical Compound?

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. The name of given molecule is Ethylamine. The functional group that is present in the given molecule is ammine.

Therefore, the correct option is option B that is Ethylamine.

To learn more about chemical compound, here:

brainly.com/question/26487468

#SPJ2

Is the following compound an alcohol, aldehyde, or organic acid?
C-C=0

Answers

Answer:

Explain both aldehydes and ketones, the geometry around the carbon atom in the carbonyl group is trigon planar; the carbon atom exhibits sp2 hybridization. Two of the sp2 orbitals on the carbon atom in the carbonyl group are used to form σ bonds to the other carbon or hydrogen atoms in a molecule. The remaining sp2 hybrid orbital forms a σ bond to the oxygen atom. The hybridized p orbital on the carbon atom in the carbonyl group overlaps a p orbital on the oxygen atom to form the π bond in the double bond.ation .

Calculate normality and tire of KOH solution , if CN H2 C2 O4 solution , that is nessesary for titration is 0.1050 mol/1 and the Volume is 5.0 ml ; the volume of KOH - solution is 4.5 ml

Answers

Answer:

Normality of KOH = 0.1062 N

Note: The given question is not clearly stated. A related question below is answered and explained;

What is the NORMALITY of a solution of KOH if 45.18 mL are required to neutralize 0.3g of pure oxalic acid H2C2O4 . 2H2O?

Explanation:

Equation of the reaction: 2KOH + H₂C₂O₄.2H₂O --> K₂C₂O₄ + 4H₂O

molar mass 0f KOH = 56 g/mol; molar mass of H₂C₂O₄.2H₂O = 126 g/mol

Number of moles of in 0.3 g of H₂C₂O₄.2H₂O = mass/molar mass

number of moles = 0.3 g / 126 g/mol = 0.0024 moles

From the equation of reaction, 2 moles of KOH are required to neutralize 1 mole of H₂C₂O₄.2H₂O

Number of moles of KOH required to neutralize 0.0024 moles of H₂C₂O₄.2H₂O = 2 * 0.0024 = 0.0048 moles

Molar concentration of 45.18 mL solution of KOH containing 0.0048 moles of  KOH = number of moles/volume (L)

molarity of KOH solution = (0.0048/45.18 mL) * (1000 mL/1 L) = 0.1062 mol/L

Normality = n * molarity

where is the number of moles of OH⁻ ions produces from  mole of KOH = 1

Normality of KOH = 1 * 0.1062

Normality of KOH = 0.1062 N

Name the following molecules:



P4S5______________________________________________



CH4______________________________________________



NF3 ______________________________________________



N2O______________________________________________

Answers

not sure about P4S5, but CH4 is Methane, NF3 is Nitrogen trifluoride, and N2O is Nitrous oxide.

Answer in two or three sentences

Why do you believe knowing how elements and compounds react together is essential in everyday matters?

Answers

Answer:

Knowing how elements and compounds react together is essential in everyday life is essential to people like a scientist and someday you might become a scientist no matter what you become you will have to learn all that you can.

UwU Hope I helped

Answer:

it is very important to know how elements and compounds react together because everything that surrounds us is made out of elements and compounds. Therefore, understanding how these work can allow us to have a better understanding of the world that surrounds us. Moreover, it can avoid accidents when we deal with dangerous compounds, such as when we cook or clean

Explanation:

please help out correct answers only

Answers

Answer:

Molecular formula = SF₆

Empirical formula is SF₆

Explanation:

Percentage of sulfur = 21.95%

Percentage of fluorine = 78.03%

Molar mass of compound = 146.1 g/mol

Empirical formula = ?

Molecular formula = ?

Solution:

Number of gram atoms of S = 21.95 / 32= 0.69

Number of gram atoms of F = 78.03 / 19 =  4.107

Atomic ratio:

                                  S                  :         F

                                0.69/0.69      :       4.107/0.69

                                     1                :         6

S : F =  1:6

Empirical formula is SF₆

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

Empirical formula mass :

32 + 19×6 = 146

n = 146.1 / 146

n = 1

Molecular formula = n (empirical formula)

Molecular formula = 1 (SF₆)

Molecular formula = SF₆

The climate in the temperate deciduous forest biome has four changing seasons with rain.
True
False

Answers

The answer is false.
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