Q2: A compound consists of 40.00 % C, 6.67 % H and
rest is oxygen by mass. If RMM of X is 180, find the
molecular formula.​

Answer:

-0.398

Explanation:

pOH is a measure of hydroxide ion (OH-) concentration in a solution. A basic solution If a solution has pOH less than 7 then it is a basic solution and if  pOH is greater than 7 then it is an acidic solution. Neutral solutions have pOH equal to 7.

[tex]pOH=-\log \left [ OH^- \right ][/tex]

To find pOH of 2.5 M NaOH, solve [tex]pOH=-\log \left [ 2.5 \right ][/tex] = -0.398

Answer:

When a Magnesium Ribbon is burnt, a powdery substance called magnesium oxide is formed.

Explanation:

There has obviously been a chemical change because several chemical properties of the magnesium have been modified:  the color, the texture and the mass.

The increase in mass is due to the fact that oxygen from the air has combined with the magnesium to make magnesium oxide, MgO.

The chemical equation, Mg + O2  MgO shows this reaction but it needs to be balanced to make 2Mg + O2  2MgO.  

Using stoichiometry, we can convert this eqation into an equation with moles:  

2 mol Mg + 1 mol O2  2 mol MgO.  

Next, we convert to grams using atomic masses obtained from the periodic table:

48g Mg + 32g O2  80g MgO

Lastly, we determine the same thing in the proportions we used.  In other words, we used only 0.15g of Mg (not 48g) so everything needs to be divided by 320.  So 80 / 320 = 0.25 g.  If we burn 0.15 g of Mg, we obtain 0.25 g of MgO.

Hope this helps!!!

This is my first answer.

Answer:

1.20 L = 1200 mL

Explanation:

P1V1/T1 = P2V2/T2

V2 = P1*V1*T2/(T1*P2)

V1 = 700ml =0.700 L

P1 = 106.6 kPa

T1 = 7+273.15 = 280.15 K

T2 = 27 + 273.15 = 300.15 K

P2 = 66.6 kPa

V2 = 106.6*0.700*300.15/(280.15*66.6)= 1.20 L=1200 mL

Answer:

The answer is Diffusion.

Explanation:

Diffusion is a movement of molecules(substances) from a region of high concentration to a region of low concentration down a concentration gradient.

Answer:

Active

Explanation:

During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy.

Answer: 6 mol Li

Explanation:

The first step is to balance the equation.

2Li+Cl₂⇒2LiCl

We would need our conversions to find the amount of moles of Li needed to produces 6 mol LiCl.

[tex]6molLiCl*\frac{2molLi}{2molLiCl} =6molLi[/tex]

Answer:

1) A

2) D

3) A

4) B

5) D

6) C

7) B

8) A

9) C

10) C

Explanation:

Sublimation refers to the direct change of a substance from solid to gas without passing through a liquid stage. Hence if camphor changes directly from solid to gas, camphor is a sublime substance.

Gases have a higher rate of diffusion than liquids because liquids have greater intermolecular forces while the intermolecular forces in a gas is negligible.

When a substance is heated, a point comes in which heat is supplied but the temperature of the body does not change. This is the point of phase change and the heat supplied at this point may be referred to as latent heat of fusion or vaporization depending on the particular process going on.

While it is true that evaporation occurs at all temperatures and the kinetic energy of molecules is directly proportional to the temperature of a body but the later statement does not explain the former. Rather evaporation occurs because some particles at the surface of the liquid are more energetic and escape due to unbalanced attractive forces acting on them.

Due to decrease in temperature, it takes a longer time to cook food at high altitudes but a lesser time to boil water at higher altitudes.

Gases are easily compressible by applying pressure because gases occupy negligible volume compared to the volume of the container. There is a significant inter particle space between gas particles.

The solid state contains the strongest degree of intermolecular forces. However, the reason offered, though correct, is not the correct explanation of the assertion stated.

This is the Tyndall effect. Colloidal particles scatter light rays and the path of the light becomes visible in the colloidal solution.

Salt solution is homogeneous. A homogeneous solution contains only one phase throughout. If it has a different composition, the solution is heterogeneous. Hence the explanation is false.

A true solution will not exhibit Tyndall effect because the particles are less than colloidal size. A true solution cannot be a heterogenous mixture hence the reason is false.

Answer:

Hope it helps you!

Answer Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to produce energy. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy in order to build their structural components, survive, grow and reproduce.

Explanation:

The  source of chemical energy from wood can be renewed as wood can constantly obtain chemical energy from the sun as it is a renewable source of energy.

Energy which is stored in the chemical bonds of chemical compounds is called chemical energy.Chemical energy is released during the occurrence of chemical reaction.Reactions wherein energy is given out in the form of heat is called exothermic reactions.

Chemical energy can be converted to other forms of energy like electrical energy during the process of electrolysis and to thermal energy as in the case of thermal engines.

It can also be converted to kinetic energy during explosions . It is stored in batteries, coal, biomass, food, vehicle air bags,etc.Chemical energy of plants is utilizes during the process of photosynthesis.

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Answer:

487 moles of CO2 is needed

Explanation:

What we need to use here is the ideal gas equation.

Mathematically;

PV = nRT

Since we are calculating the number of moles, we can rewrite the equation to be;

n = PV/RT

from the question, we identify the following;

P is the pressure at 150 atm

V is the volume at 80L

T is the temperature which is 27+273 = 300K

R is the molar gas constant which is 0.0821 L atm K^-1 mol^-1

Substituting these values, we have;

n = (150 * 80)/(0.0821 * 300) = 487.2 which is approximately 487 moles

Answer: D

Explanation:

the atom of the metal loses one electron which becomes delocalised and is attragted by the positive nucleus leading to formation of metallic bond.

E. They form because electrons can move freely between atoms

Top guy is incorrect↑

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Answer:

THE pH OF THE SOLUTION IS 1.28

Explanation:

Step 1: Calculate the mass concentration of HCl

398 mg in 210 mL

1 L = 10^3 mL

1 g = 10^3 mg

398 *10^-3 g in 210 *10^-3 L

398 *10^-3 in 0.210 L

mass concentration = (0.398 * 1/ 0.210) g/dm3

= 1.895 g/dm3

Step 2: calculate the molar concentration

Molar mass of HCl = ( 1 + 35.5) = 36.5 g/mol

Molar concentration = mass concentration / RMM

Molar conc. = 1.895 / 36.5

Molar conc. = 0.0519 mol/dm3

So therefore, the molar concentartion of the solution is equal to the concentration of HCl.

In other words, [HCl] = 0.0519 mol/dm3

This shows that at 1 L of this solution contains 0.0519 moles of HCl

Step 3: write the dissiociation equation of HCl in water

HCl(aq) + H2O(l) --------> H30^+ (aq) + Cl- (aq)

Since HCl is a strong acid, it will dissociate completely in water forming the above products.

So we can say that:

[H3O+] = [HCl] = 0.0519 moles/ dm3

Step 4: calculate the pH

pH = -log[H3O+]

pH = -log (0.0519)

pH = 1.28(3 significant decimal place)

The pH of the solution is 1.28

Answer:

Forumula

XOH + HY = XY + H2O

Explanation:

Salt formed from: Salt Solution

Strong acid + Strong base Neutral

Strong acid + Weak base Acidic

Weak acid + Strong base Basic

Neutral solution example

NaCl = Sodium chloride

HCl = H+ and Cl-

NaOH = Na+ and OH-

OH- = Strong Base

H+ = Strong Acid

Sodium chloride, formed from neutralization of HCl by NaOH.

NaOH + HCl = NaCl + H2O

NaCl in water is not acidic or basic, since it's ions cannot hydrolyze.

So formula would be XOH + YH = XY + H2O

Answer:

0.74M

Explanation:

Step 1 :

Data obtained from the question.

Initial concentration (C1) = 3M

Initial volume (V2) = 185mL

Final volume (V2) = 750mL

Final concentration (C2) =..?

Step 2:

Determination of the new concentration of the solution.

The new concentration of the solution can be obtained by using the dilution formula as shown below:

C1V1 = C2V2

3 x 185 = C2 x 750

Divide both side by 750

C2 = 3 x 185 / 750

C2 = 0.74M

Therefore, the new concentration of the solution is 0.74M

Answer: 7.6 g of water are required to make 12.6 g of glucose

Explanation:

Moles is calculated by using the formula:

[tex]Moles=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

[tex]{\text {moles of glucose}}=\frac{12.6g}{180g/mol}=0.07moles[/tex]

The balanced chemical equation is:

[tex]6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2[/tex]

According to stoichiometry:

1 mole of glucose is produced by = 6 moles of water

Thus 0.07 moles of glucose is produced by =[tex]\frac{6}{1}\times 0.07=0.42[/tex] moles of water

Mass of water required =[tex]moles\times {\text {Molar mass}}=0.42mol\times 18g/mol=7.6g[/tex]

Thus 7.6 g of water are required to make 12.6 g of glucose

Answer:

Explanation:

Two possible changes are

Explanation:

Molarity = M = mol/1 liter

in sol 250 mL there are KNO3 2.02 mol

in sol 1000 mL there are KNO3 = 2.02/250 × 1000

= 8.08 mol/liter

Answer:

true

no explanation

Answer:

element and compound.

Explanation:

reason

an element is a pure substance that cannot be broken down into simpler substances by any ordinary physical or chemical process.

and compound is a pure substance that consists of two or more elements held together in fixed proportions by natural forces called chemical bonds.

homogeneos and heterogenous mixtures are considered impure substances because they dont have a definite composition.

In chemistry, pure substances have been defined by matter that has characteristic properties. An element and compound are pure substances. Thus, options 1, and 2 are correct.

Pure substances have been the matter that is characterized by the presence of a fixed chemical composition that cannot be physically separated by the processes like filtration, evaporation, etc.

Elements and compounds are pure substances as elements are not broken physically or chemically to form simple -small substances like zinc. Furthermore, compounds are formed by the combination of pure substances like water.

Homogeneous mixtures and heterogeneous mixtures are not pure substances as they lack fixed ratios and proportions that cannot be said to have definite composition.

Therefore, options 1 and 2. are elements and compounds are pure substances.

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Answer:

C4H8. butene

Explanation:

47.0g is the mass of ammonia

Answer:

Ve explicación abajo

Explanation:

Responderemos esta pregunta en dos partes.

PAra la primera parte, usaremos la expresión de gases ideales la cual es:

PV = nRT (1)

Donde:

P: Presión (atm)

V: Volumen (L)

n: moles

R: constante universal de gases (0.082 L atm/ mol K)

T: Temperatura (K)

En este caso, tenemos un recipiente que se llena completamente de oxígeno (O₂) hasta 3 L. Este sería su volumen. a la presión de 740 mmHg, esta es la presión y debemos convertirla a atmosfera, y la temperatura de 10 °C que debe ser convertida a Kelvin. Con esos datos se puede calcular primero los moles de oxigeno y luego los gramos.

Transformando las unidades de presión y temperatura tenemos:

P = 740 mmHg * 1 atm / 760 mmHg = 0.974 atm

T = 10 + 273 = 283 K

Con estos datos, usaremos la expresión (1) para calcular los moles:

n = PV / RT

n = 0.974 * 3 / 0.082 * 283

n = 0.1259 moles

Con estos moles, se pueden calcular los gramos usando el peso molecular del oxigeno que es 16 g/mol. (Como tenemos 2 atomos, serían 32 g/mol):

m = n * PM

m = 0.1259 * 32

m = 4.0288 g

Ahora que tenemos la masa se puede calcular la densidad con la siguiente expresión:

d = m/V

Usando el volumen en mililitros (3 * 1000 = 3000 mL) y la masa obtenida, calculamos entonces la densidad.

d = 4.0288 / 3000

d = 0.00134 g/mL

Para la segunda y ultima parte del ejercicio, usaremos la ley de boyle donde se mantiene el volumen constante (en este caso 3 L) y solo se altera presión y temperatura. De esta forma calcularemos la temperatura necesaria para que la presión se reduzca a la mitad:

P₁/T₁ = P₂/T₂

Y queremos saber es la temperatura para que la presión sea la mitad de la presión inicial, por tanto:

P₂ = 1/2P₁

Sabiendo que la temperatura es de 10 °C (283 K) tenemos entonces:

P₁/T₁ = P₁/2T₂     Se cancelan las presiones y nos queda

1/T₁ = 1/2T₂

2T₂ = T₁

T₂ = 1/2T₁

Reemplazando la temperatura:

T₂ = 283 / 2

T₂ = 141.5 K

the le answer to dis problem is neon. it has 10 protons

Answer:

Magnesium

Explanation:

Using the KLMN styled electronic configuration, the electronic configuration of sulphur with atomic number 16 is 2, 8,6

What this means is that it needs extra 2 electrons to fill into its M shell to attain the octet configuration.

Now let’s look at Magnesium, with atomic number 12, the electronic configuration it has is 2,8,2.

This means it has 2 extra electrons to give away so as to attain its own stability.

The sulphur atom will gladly accept the two electrons which the magnesium atom wants to give away. This makes it the perfect element to be reacted with sulphur to make it attain its octet configuration

Answer:

4 H2 + 1 O2 = 2 H2O

Answer:

Second graph is more reactive.

Explanation:

I just did the lesson myself, chose the first graph, and obviously got it wrong.

Therefore I can tell you with 100% certainty that the correct answer is graph #2 in this case.  Hope this helps.

Answer:

the scientist who studied the movement of pollen grains grains suspended in water through a microscope is Robert Hooke

Answer:

0.136 L = 136 mL

Explanation:

18.0M = 18.0 mol/L

2.45 mol /(18.0 mol/L) = 0.136 L = 136 mL

Answer:

C6H6

Explanation:

Just use the table method to find the ratio of C to H and then compare the RMM with that of the empirical formula.

Answer:

C6H6

Explanation:

We divide each percentage by the relative atomic mass of the element:

Carbon:  92.31 / 12.011 = 7.68

Hydrogen:  7.69 / 1.008 = 7.63

So the ratio of carbon to hydrogen is 1:1.

Empirical formula is CH  - which has a  MM of 13.019

The RMM is 78 so the molecular formula = 78/13.019 = 6 * CH

So it is C6H6  (Benzene).

Answer:

Explanation:

The Kudzu is a plant that was introduced to the United States from Japan in the year 1876. In the United States it was introduced as an ornamental plant but with a reason which was to prevent soil erosion. Kudzu was disseminated as being high-protein content used to steer feed as well as a spreading plant to counteract soil erosion.

Answer:

Kudzu was introduced as an ornamental plant.

+

Kudzu was introduced as a way of preventing soil erosion.

So, A and D!