Calculate the empirical formula of a compound with the following
percentage composition: 31,8% K; 29,0% C1; 39,2% O
The empirical formula of ethane is CH. Its molar mass is 30 g.mol-

Answer:

GOOD DAY ON YOUR QUIZ

Explanation:

Answer:

The correct answer is 116.3 g/mol

Explanation:

When a solute is added to a solvent, the freezing point decreases. That is called freezeing point depression and is given by the following expression:

ΔTf= Kf x m

Where ΔTf is the decrease in freezing point (final temperature - initial temperature), Kf is the freezeing point constant, m is the molality of the solution.

We have the following data:

Kf= 5.12ºC/m

ΔTf= 5.48ºC - 3.77ºC = 1.71ºC

We can calculate the molality of the solution from the mathematical expression for freezeing point as follows:

m = ΔTf/Kf = 1.71ºC/(5.12º C/m)= 0.334 m

The molality is the number of moles of solute in 1 kg of solvent. The solute was added to 500 g of solvent (benzene), so we can multiply the molality by the grams of solvent (500 g = 0.5 kg) to obtain the number of moles:

0.334 mol/kg x 0.5 kg = 0.172 moles

We know that the molar mass is equal to the mass of compound per mole, so we divide the mass into the moles to obtain the molar mass as follows:

MM = mass/moles= 20.0 g/0.172 moles = 116.3 g/mol

Answer:

The molecular solids would have the lowest boiling point because of WEAK INTERMOLECULAR FORCES.

Explanation:

Answer: One with induced dipole attractions

Answer:

198.8mL

Explanation:

Step 1:

Data obtained from the question:

Molarity of base (Mb) = 3.5M

Volume of base (Vb) =..?

Molarity of acid (Va) = 2.75M

Volume of acid (Va) = 253mL

Step 2:

The balanced equation for the reaction.

HF + LiOH —> LiF + H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 1

The mole ratio of the base (nB) = 1

Step 3:

Determination of the volume of the base, LiOH needed for the reaction.

The volume of the base needed for the reaction can be obtained as follow:

MaVa /MbVb = nA/nB

2.75 x 253 / 3.5 x Vb = 1

Cross multiply

3.5 x Vb = 2.75 x 253

Divide both side by 3.5

Vb = 2.75 x 253 / 3.5

Vb = 198.8mL

Therefore, the volume of the base needed for the reaction is 198.8mL

Answer:

botany because a maple tree is a plant

Explanation:

Answer:

melting

Explanation:

Answer:

65450 in^3

Explanation:

Someone deleted my old answer

Answer:

Mass of precipitate (PbSO₄) formed = 0.696 g

Explanation:

The reaction of Lead II Nitrate and Sodium Sulfate is given as

Pb(NO₃)₂ (aq) + Na₂SO₄ (aq) → 2NaNO₃ (aq) + PbSO₄ (s)

The precipitate from this reaction is the PbSO₄

0.76 g of Pb(NO₃)₂ is available for reaction, we convert to number of moles

Number of moles = (Mass)/(Molar Mass)

Mass = 0.76 g

Molar mass of Pb(NO₃)₂ = 331.2 g/mol

Number of moles of Pb(NO₃)₂ = (0.76/331.2) = 0.002294686 moles = 0.002295 moles

25.00 ml of 0.2010M sodium sulfate is available for the reaction, we also conert to number of moles.

Number of moles = (Concentration in mol/L) × (Volume in L)

Concentration of Na₂SO₄ in mol/L = 0.201 M

Volume of Na₂SO₄ in L = (25/1000) = 0.025 L

Number of moles of Na₂SO₄ = 0.201 × 0.025 = 0.005025 moles

From the stoichiometric balance of the reaction, 1 mole of Pb(NO₃)₂ reacts with 1 mole of Na₂SO₄

Hence, this indicates that Pb(NO₃)₂ is the limiting reagent as it is in short supply and it will therefore dictate the amount of precipitate (PbSO₄) formed.

1 mole of Pb(NO₃)₂ gives 1 mole of the precipitate (PbSO₄)

0.002295 mole of Pb(NO₃)₂ will give 0.002295 mole of the precipitate (PbSO₄)

Mass = (Number of moles) × (Molar mass)

Number of moles of precipitate (PbSO₄) formed = 0.002295 mole

Molar mass of PbSO₄ = 303.26 g/mol

Mass of precipitate (PbSO₄) formed = 0.002295 × 303.26 = 0.6958864734 = 0.696 g

Hope this Helps!!!

Answer:

We need blood cholesterol because our body uses it to build your structure of cell membranes, make hormones like oestrogen, and testosterone, and to help your metabolism work well.

Answer:

our cells need some cholesterol but too much cuz it can cause problems. HDL carries cholesterol to your liver, where it can be removed from the body.so it  helps protect your heart from atherosclerosis

Explanation:

The given question incomplete, the complete question is:

In the Hall-Heroult process, a large electric current is passed through a solution of aluminum oxide (Al,03) dissolved in molten cryolite (Na, Alts).re in the reduction of the Al, o, to pure aluminum. Suppose a current of 1800. A is passed through a Hall-Heroult cell for 37.0 seconds. Calculate the mass of pure aluminum produced Be sure your answer has a unit symbol and the correct number of significant digits.

Answer:

The correct answer is 6.2114 grams.

Explanation:

Based on the given question, the value of current or I have given is 1800 amperes, the time given is 37 seconds, and there is a need to find the mass of the pure aluminum generated in the process. Mass or weight can be determined by using Faraday's first law equation, that is, w = MIt/nF.  

Here, M is the atomic mass, w is the weight of the substance deposited, t is time, I is current, n is the number of moles of the electron, and F is the Faraday's constant, which is 96500 C. In the process mentioned in the question, aluminum oxide is reduced to give rise to pure aluminum, and in the process 3 electrons are gained. So, the value of n will be 3. The M or the atomic mass of Al is 27 gm per mole. Now putting the values in the equation we get,  

w = 27*1800*37 / 3*96500

w = 1798200 / 289500

w = 6.2114 grams

Hence, pure aluminum produced in the process is 6.2114 grams.  

Answer:

0.188 moles

Explanation:

moles=mass/molar mass

moles= 19.2/ (32+32+38)

moles= 0.188

Answer:

0.188 moles.

Explanation:

Molar mass of SO2F2

=  32 + 2*16 + 2 * 19

= 102 g.

So 19.2g = 19.2 / 102

= 0.188 moles.

Answer:

D

Explanation:

Your supervisor is in charge of you so therefore you must always tell your supervisor first.

Answer:

C.

Explanation:

Because you might get hurt, could be dangerous.

Answer:

23.3mL of 0.150M sodium thiosulfate

Explanation:

The  net reaction of sodium hypochlorite (NaClO) with sodium thiosulfate (Na₂S₂O₃) is:

NaClO + 2 Na₂S₂O₃ + 2H₃O⁺ → NaCl + 3 H₂O  +  Na₂S₄O₆ + 2 Na⁺

2.0mL of the sample of bleach are:

2.0mL ₓ (1.084g / mL) ₓ (6 / 100) ₓ (1 mol / 74.44g) = 1.75x10⁻³ moles of NaClO

As 1 mole of NaClO reacts with 2 moles of thiosulfate:

1.75x10⁻³ moles of NaClO ₓ (2 mol Na₂S₂O₃ / 1 mol NaClO) =

3.50x10⁻³ moles of Na₂S₂O₃

If you have a 0.150M solution of thiosulfate, mL of this solution you need to reach the end point of the titration are:

3.50x10⁻³ moles of Na₂S₂O₃ ₓ (1L / 0.150mol) = 0.0233L =

Answer:

1.25 g

Explanation:

Now we have to use the formula;

N/No = (1/2)^t/t1/2

N= mass of cesium-137 left after a time t (the unknown)

No= mass of cesium-137 present at the beginning = 5.0 g

t= time taken for 5.0 g of cesium-137 to decay =60 years

t1/2= half life of cesium-137= 30 years

Substituting values;

N/5= (1/2)^60/30

N/5= (1/2)^2

N/5= 1/4

4N= 5

N= 5/4

N= 1.25 g

Therefore, 1.25 g of cesium-137 will remain after 60 years.

Answer:

c

Explanation:

1 [tex]cm^{3}[/tex] = 1 mL

20,6 mL = 20,6 [tex]cm^{3}[/tex]

Answer:

C-20.6 cm^3

Explanation:

Cubic centimeters directly correspond to mL. Thus the answer would be the same as the mL

Answer:

[Cl⁻] = 0.016M

Explanation:

First of all, we determine the reaction:

Pb(NO₃)₂ (aq) + MgCl₂ (aq) → PbCl₂ (s) ↓  +  Mg(NO₃)₂(aq)

This is a solubility equilibrium, where you have a precipitate formed, lead(II) chloride. This salt can be dissociated as:

           PbCl₂(s)  ⇄  Pb²⁺ (aq)  +  2Cl⁻ (aq)     Kps

Initial        x

React       s

Eq          x - s              s                  2s

As this is an equilibrium, the Kps works as the constant (Solubility product):

Kps = s . (2s)²

Kps = 4s³ = 1.7ₓ10⁻⁵

4s³ = 1.7ₓ10⁻⁵

s =  ∛(1.7ₓ10⁻⁵ . 1/4)

s = 0.016 M

Answer:

See attachment.

Explanation:

Mono-substituted cyclohexanes are more stable with their substituents in an equatorial position. However, with poly-substituted cyclohexanes, the situation is more complex since the steric effects of all substituents have to be taken into account. In this case, you can see that the interconversion is shifted towards the conformation in the bottom because there is less tension between the substituents.

Answer:  The property is called Luster

Explanation:

Luster is a term used to describe the appearance of  light from the surface of the mineral when it reflects light. The two types of classification of Luster is Mettalic or Non Mettalic.

some examples of minerals with mettalic lustre are --- Galena, graphite, Gold, Silver, Copper etc

Some examples of minerals with non mettalic lustre are--- Barite, Serpentine, Fluorite etc.

Answer:

Lustrous property

Explanation:

Materials like metals that have lustre usually glow or display sheen when light comes in contact with the surface of the material.

It is derived from the Latin word "lux" meaning "light", which is indicative of radiance or gloss.

Lustre is a common property of metals, including sonourousity, malleability and ductility amongst others.

Answer:

Explanation:

Hello,

We are required to write the chemical formula of the following compounds

1. Calcium nitride = Ca₃N₂

2. Magnesium Phosphide = Mg₃P₂

3. Rubidium Chromate = Rb₂CrO₄

4. Aluminium nitrate = Al(NO₃)₃

5. Ammonium Arsenide = (NH₄)₃As

6. Nickel(ii) nitrite = Ni(NO₂)₂

7. Copper(i)sulfate = Cu₂SO₄

8. Iron(iii)nitrate = Fe(NO₃)₃

9. Manganese(ii)nitrate = Mn(NO₃)₂

The left hand side are the common names when the right hand side are the chemical formula.

1. Octagon (8 sides)

2. Hexagon (6 sides)

3. Pentagon (5 sides)

4. Square/Rectangle (4 sides)

5. Triangle (3 sides)

Hope this helps :)

Answer:

9.36g of H2O.

Explanation:

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

2Na + 2H2O —> 2NaOH + H2

Next, we shall determine the mass of Na and H2O that reacted from the balanced equation.

This is illustrated below:

Molar mass of Na = 23g/mol

Mass of Na from the balanced equation = 2 x 23 = 46g

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H2O from the balanced equation = 2 x 18 = 36g

From the balanced equation above,

46g of Na reacted with 36g of H2O.

Now, we can determine the mass of H2O involved in reaction as follow:

From the balanced equation above,

46g of Na reacted with 36g of H2O.

Therefore, 11.96g of Na will react with = (11.96 x 36)/46 = 9.36g of H2O.

Therefore, 9.36g of H2O were used for the reaction.

Answer:

27.6mL of LiOH 0.250M

Explanation:

The reaction of lithium hydroxide (LiOH) with chlorous acid (HClO₂) is:

LiOH + HClO₂ → LiClO₂ + H₂O

That means, 1 mole of hydroxide reacts per mole of acid

Moles of  20.0 mL = 0.0200L of 0.345M chlorous acid are:

0.0200L ₓ (0.345mol / L) = 6.90x10⁻³ moles of HClO₂

To neutralize this acid, you need to add the same number of moles of LiOH, that is 6.90x10⁻³ moles. As the LiOH contains 0.250 moles / L:

6.90x10⁻³ moles ₓ (1L / 0.250mol) = 0.0276L of LiOH =

Answer:

Erosion.

Explanation:

Erosion is the act of loose soil crumbling under itself and causes it to slide down a hill.

Answer:

erosion

Explanation:

Answer:

1) Option A is correct.

The covalent bond is the chemical bond that is established by pooling of electrons.

2) Option B is correct.

The covalent bond is established between two non-metals.

3) Option B is correct.

A covalent bond is established between nitrogen and hydrogen.

4) Option B is correct.

Covalent bonds are of two types; polar covalent bonds and non-polar covalent bonds.

5) Option B is correct.

Select the substances in the molecules of which the atoms are united by ionic bond.

potassium chloride KCl

1) Opțiunea A este corectă.

Legătura covalentă este legătura chimică care se stabilește prin punerea în comun a electronilor.

2) Opțiunea B este corectă.

Legătura covalentă este stabilită între două nemetale.

3) Opțiunea B este corectă.

Se stabilește o legătură covalentă între azot și hidrogen.

4) Opțiunea B este corectă.

Legăturile covalente sunt de două tipuri; legături covalente polare și legături covalente nepolare.

5) Opțiunea B este corectă.

Selectați substanțele din moleculele cărora atomii sunt uniți prin legătură ionică. clorură de potasiu KCl

Explanation:

English Translation

1) The covalent bond is the chemical bond that is established: a) by pooling electrons; b) by electron transfer; c) by pooling or electron transfer.

2) The covalent bond is established between: a) two metals; b) two non-metals; c) a metal and a non-metal.

3) A covalent bond is established: a) between hydrogen and sodium; b) between nitrogen and hydrogen; c) between aluminum and oxygen.

4) Covalent bonds are of two types: a) single covalent bonds and double covalent bonds; b) polar covalent bonds and non-polar covalent bonds; c) no answer is correct.

5) Select the substances in the molecules of which the atoms are united by ionic bond: a) phosphorus oxide P2O5; b) potassium chloride KCl; c) H2O water

Solution

Covalent bonds are bonds that result from the sharing/pooling of electrons by two non-metallic atoms. When the electronegativity difference between the two atoms in a cobalent bond is substantial, a polar covalent bond results (in which the shared electrons are closer to the more electronegative atom of the pair). If the electronegativity difference isn't significant, a non-polar covalent bond ensues, in which the shared electrons are approximately equidistant from both atoms.

1) The covalent bond is the chemical bond that is established by pooling of electrons.

Already explained above.

2) The covalent bond is established between two non-metals.

Already explained too.

3) A covalent bond is established between nitrogen and hydrogen.

Of the three options, only option B contains two elements, nitrogen and hydrogen, which are both non-metals amd this satisfy the condition for the formation of a covalent bond.

4) Covalent bonds are of two types; polar covalent bonds and non-polar covalent bonds.

Already explained above.

5) Select the substances in the molecules of which the atoms are united by ionic bond.

potassium chloride KCl

Ionic bonds result from the transfer of electrons from metals (electropositive elements) to non-metals (electronegative elements). Of the 3 options provided, only potassium chloride is a coming together of a metal and a non metal.

In Romanian/In limba romana

Legăturile covalente sunt legături care rezultă din împărțirea / îmbinarea electronilor de către doi atomi nemetalici. Când diferența de electronegativitate între cei doi atomi dintr-o legătură cobalentă este substanțială, rezultă o legătură covalentă polară (în care electronii partajați sunt mai apropiați de atomul mai electronegativ al perechii). Dacă diferența de electronegativitate nu este semnificativă, apare o legătură covalentă non-polară, în care electronii partajați sunt aproximativ echidistanți de la ambii atomi.

Legăturile ionice rezultă din transferul electronilor de la metale (elemente electropozitive) la nemetalele (elemente electronegative).

Hope this Helps!!!

Sper că acest lucru vă ajută!!!!

Answer:

Second law of thermodynamics.

Explanation:

Second law of thermodynamics states the entropy or order in an isolated system always increases. The isolated system evolve spontaneously toward thermal thermal equilibrium.

For example if a room is untidy and dirty,it will become messy over time and disorder. So when the room is cleaned, there won't be disorderliness and entropy will decrease.

Answer:

The reaction is a double displacement reaction

Explanation:

Let us consider the reaction equation of the reaction between ammonium oxalate and lithium acetate.

(NH4)2C2O4(aq) +2 CH3COOLi(aq) -------> 2NH4CH3CO2(aq) + Li2C2O4(s)

This is a displacement reaction. A double displacement reaction is a type of reaction in which two reactants exchange their ions to form two new compounds. Double displacement reactions usually lead to the formation of a solid product which is also called a precipitate.

The general form of a Double displacement reaction is of the format:

AB + CD → AD + CB

Where A,B,C and D represents different ions respectively.

A double displacement reaction can also be referred to as salt metathesis reaction, double replacement reaction, exchange reaction, or a double decomposition reaction, although the latter term is more strictly used when one or more of the reactants does not dissolve in the solvent.

Answer:

The pressure at equilibrium of Br₂ is 0.10048 atm

Explanation:

Based on the reaction:

Br₂(g) + 3 F₂(g) ⇄ 2 BrF₃(g)

Kp is defined as:

[tex]Kp = \frac{P_{BrF_3}^2}{P_{Br_2}P_{F_2}^3}[/tex] = 5.4x10⁸

If initial pressures of Br₂ and F₂ are 0.30atm and 0.60atm respectively, the pressures in equilibrium are:

Br₂ = 0.30atm - X

F₂ = 0.60atm - 3X

BrF₃ = 2X

Replacing in Kp formula:

5.4x10⁸ =  [2X]² / [0.30atm - X] [0.60atm - 3X]³

5.4x10⁸ = 4X² / [0.30 - X] [0.216 - 3.24 X + 16.2 X² - 27 X³]

5.4x10⁸ = 4X² / 0.0648 - 1.188 X + 8.1 X² - 24.3 X³ + 27 X⁴

Solving for X:

X = 0.3000 → False answer because produce negative concentrations.

X = 0.19952. Replacing in equation of Br₂:

Br₂ = 0.30atm - 0.19952atm = 0.10048 atm

Answer:

139.98 g to nearest hundredth.

Explanation:

Using Avogadro's Number:

One mole (167.26 g) of Erbium  equates to  6.022141 * 10^23 atoms.

So 5.04 * 10^23 = 167.26 * 5.04/6.022141

= 139,98 g.

Answer:

A. Its temperature is uniform.

Explanation:

Cosmic Microwave Background radiation is a remnant of the Big Bang talks about the universe being very hot thereby causing its expansion with a corresponding cooling of the gases within it. The Cosmic Microwave Background radiation being what is left of the radiation after the Big Bang occurrence.

The temperature was uniform with very little fluctuations which makes the A the right choice.

Answer:

a

Explanation:

Answer:

Explanation:I don't say u must have to mark my ans as brainliest but if it has really helped u plz don't forget to thnk me...