a compound has a percent compostion of carbon equal to 48.8383%, hydrogen equal to 8.1636%, and oxygen equal to 43.1981%. what is the mepirical formula

Answer:

Haematology is the specialty important for the diagnosis and management of a wide range of benign and malignant disorders of the red and white blood cells, platelets and the coagulation system in adults and children.

Answer:

cm3 = 2500.0 g / 10.5 g/cm3 = 238 cm3

Answer:

Sorry but i don't undertsnad the question.

Explanation:

Answer:

A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape, color, texture, flexibility, density, and mass.

A chemical change happens when one chemical substance is transformed into one or more different substances, such as when iron becomes rust.

Do u want examples ?

385 x 42.13 x 0.079 = 1281.38395

Answer:

+0.151, spontaneous

Explanation:

Given that;

Co^2+(aq) + 2e ---->Co(s) -0.28 V

Pb^2+(aq) + 2e ---->Pb(s). -0.13 V

Hence Co is the anode and Pb is the cathode

E°cell = E°cathode - E°anode

So;

E°cell = -0.13 V - (-0.28 V)

E°cell = 0.15 V

The cell reaction is spontaneous since E°cell is positive.

Answer:

Radical chain initiator

Explanation:

The peroxide here serves as a radical chain initiator. In the field of chemistry the radical initiatives are those substances that are used in industrial processes like polymer synthesis. These initiatives have weak bonds generally and they're mostly used to create free radicals. These radicals are atoms that have odd numbers of electrons. Peroxide is an example of such.

Answer:c

Explanation:

Answer:

The answer is "17200 years".

Explanation:

Given:

[tex]A = 20 \ \frac{counts}{minute}\\\\A_{o} = 160\ \frac{counts}{minute}[/tex]

Let the half-life of carbon-14, is beta emitter, is [tex]T = 5730\ years[/tex]

Constant decay [tex]\ w = \frac{0.693}{ T}[/tex]

[tex]= 1.209 \times 10^{-4} \ \frac{1}{year}\\[/tex]

The artifact age [tex]t= ?[/tex]

[tex]A = A_{o} e^{-wt} \\\\e^{-wt} = \frac{A}{A_{o}}\\\\-wt = \ln \frac{A}{A_{o}}\\\\= -2.079\\\\t = 1.7199 \times 10^{4} \ years\\\\\sim \ 17200\ years\\[/tex]

I first converted the given grams of the reactants into moles, and then divided the moles by the coefficients in front of each of the reactant. The result with the smallest value will be the limiting reactant, and the value of CuO was the smallest, so it's the limiting reactant.

After figuring out which reactant is the limiting one, I took their given grams and converted it into moles, the divided it by the ratio of N2 to CuO (it's in the equation) to obtain the moles of N2, and then multiply it with the molar mass of N2 to get its mass in grams.

Answer:

They have a rock surface composition.

Explanation:

I hope this will help you

Answer:

The correct answer is option ( D )

Explanation:

Hope it helps you

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1.42liters, which is equivalent to 3pints, of blood is required for the surgery

1 US pint = 0.473 liters

3 × 0.473

= 1.419 liters of blood for the surgery

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Answer:

Explanation:

418.4kj is the correct answer

Answer:

a) 4p ⇒ 4s  transition is Allowed

b) 3d ⇒ 4s transition not allowed

Explanation:

a) 4p ⇒ 4s  transition

This transition is allowed because for a 4p state; l = 1 and for a 4s state I = 0

hence Δl = 1 - 0 = 1

Energy of 4p ( Ei ) = 3.75eV

Energy of 4s ( E2 ) = 3.19 eV

where : λ = 1240 eV nm / ( E₂ - E₁ )

                = 2214 nm ≈ 2.214 μm

b) 3d ⇒ 4s transition

This transition is not allowed  

a 3d state , l = 2 while for 4s state l = 0

hence Δl = 2 - 0 = 2

therefore the transition is not allowed

Answer:

[tex]\boxed {\boxed {\sf 4.685 \times 10^{24} \ Fe \ atoms}}[/tex]

Explanation:

We are asked to convert grams of iron to atoms of iron.

First, we convert grams to moles. We use the molar mass or the mass in 1 mole of a substance. This is found on the Periodic Table because the molar mass is equal to the atomic mass, but the units are grams per mole instead of atomic mass units. Look up iron's molar mass.

We convert using dimensional analysis, so we must set up a ratio using the molar mass.

[tex]\frac {55.84 \ g \ Fe}{ 1 \ mol \ Fe}[/tex]

We are converting 434.52 grams to moles, so we multiply by this value.

[tex]434.52 \ g \ Fe *\frac {55.84 \ g \ Fe}{ 1 \ mol \ Fe}[/tex]

Flip the ratio so the units of grams of iron cancel.

[tex]434.52 \ g \ Fe *\frac { 1 \ mol \ Fe}{55.84 \ g \ Fe}[/tex]

[tex]434.52 *\frac { 1 \ mol \ Fe}{55.84}[/tex]

[tex]\frac { 434.52}{55.84} \ mol \ Fe[/tex]

[tex]7.781518625 \ mol \ Fe[/tex]

Next, we convert moles to atoms. We use Avogadro's Number or 6.02 ×10²³. It is the number of particles (atoms, molecules, formula units, etc) in 1 mole of a substance. For this problem, the particles are atoms of iron. We set up another ratio using this number.

[tex]\frac {6.02 \times 10^{23} \ atoms \ Fe }{ 1 \ mol \ Fe}[/tex]

Multiply by the number of moles we calculated.

[tex]7.781518625 \ mol \ Fe *\frac {6.02 \times 10^{23} \ atoms \ Fe }{ 1 \ mol \ Fe}[/tex]

The units of moles of iron cancel.

[tex]7.781518625 *\frac {6.02 \times 10^{23} \ atoms \ Fe }{ 1 }[/tex]

[tex]4.68447421 \times 10^{24} \ atoms \ Fe[/tex]

The correct answer choice is Choice 3: 4.685 × 10²⁴ atoms of iron.

Answer: Uranium enrichment. Uranium is used to fuel nuclear reactors; however, uranium must be enriched before it can be used as fuel. Enriching uranium increases the amount of uranium-235 (U235) that can sustain the nuclear reaction needed to release energy and produce electricity at a nuclear power plant.

Answer:

Biphenyl

Explanation:

The reaction of bromo benzene with magnesium-ether solution yields a Grignard reagent.

The byproduct of this reaction is biphenyl. It is formed when two unreacted bromobenzene molecules are coupled together.

Hence, It is advised that the bromobenzene solution be added slowly to the magnesium-ether solution so that it isn't present in a high concentration, thus reducing the amount of biphenyl by-product formed.

Answer:

W = -120 KJ

Explanation:

Since the piston–cylinder assembly undergoes an isothermal process, then the temperature is constant.

Thus; T1 = T2 = 400K

change in entropy; ΔS = −0.3 kJ/K

Formula for change in entropy is written as;

ΔS = Q/T

Where Q is amount of heat transferred.

Thus;

Q = ΔS × T

Q = -0.3 × 400

Q = -120 KJ

From the first law of thermodynamics, we can find the workdone from;

Q = ΔU + W

Where;

ΔU is Change in the internal energy

W = Work done

Now, since it's an ideal gas model, the change in internal energy is expressed as;

ΔU = m•C_v•ΔT

Where;

m is mass

C_v is heat capacity at constant volume

ΔT is change in temperature

Now, since it's an isothermal process where temperature is constant, then;

ΔT = T2 - T1 = 0

Thus;

ΔU = m•C_v•ΔT = 0

ΔU = 0

From earlier;

Q = ΔU + W

Thus;

-120 = 0+ W

W = -120 KJ

Answer:

Answer is A.

Explanation:

The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes. :)

Answer:

Specific Heat Capacity

Answer:

Explanation:

Na2CO3+Ca(NO3)2=CaCO3+2NaNO3

nNa2CO3=0.02

nCa(NO3)2=0.02

mCaCO3=0.02*100=2 gram

nNaNo3=0.04

Cm=2/15

From the calculation, the mass of the product is 2 g.

A chemical reaction occurs when two more substances are mixed together. In this case, the reaction is shown by; Ca(NO3)2 + Na2CO3 ----> CaCO3(s) + 2NaNO3.

Number of moles of Na2CO3 = 100/1000 L *  0.2 mol/L = 0.02 moles

Number of moles of  Ca(NO3)2 = 200/1000 L *  0.1 mol/L = 0.02 moles

Since the reaction is equimolar, amount of the product = 0.02 moles * 100 g/mol = 2 g

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Answer:

COOHCOOH + 2OH⁻ ⇄  C₂O₄²⁻ + 2H₂O

Explanation:

The reaction of oxalic acid with a strong base like sodium hydroxide is the following:

COOHCOOH + OH⁻ ⇄ COOHCOO⁻ + H₂O    (1)

In this first reaction, the oxalic acid loses one proton. In a second reaction with NaOH, the ion COOHCOO⁻ loses its second proton to form ion oxalate as follows:

COOHCOO⁻ + OH⁻ ⇄ C₂O₄²⁻ + H₂O      (2)  

The general reaction between oxalic acid and NaOH is (eq 1 + eq 2):

COOHCOOH + 2OH⁻ ⇄  C₂O₄²⁻ + 2H₂O              

I hope it helps you!  

Answer:

D

Explanation:

We have to bear in mind that the acid is a weak acid. A weak acid does not dissociate completely in solution. We will have more concentration of undissociated acid than A^- and H3O^+ and OH^- in the system at equilibrium.

Being a weak acid, there is maximum concentration of water molecules followed by that of undissiociated acid.

Hence, for this solution, the concentration of ions in solution follows the order;

[H2O] > [HA] > [A-] ~ [H3O ] > [OH-]

Answer:

Anaxagoras was perhaps the first literate person to attempt to explain physical phenomena rationally, basing his ideas upon careful observations and simple experiments. This is fundamental to modern science and is the sine qua non of environmental study.

The equilibrium constant for the reaction is K = 0.137

We obtain the equilibrium constant considering the following equilibria and their constants:

COO(s) + H₂(g) → Co(s) + H₂O(g)    K₁ = 67

COO(s) + CO(g) → Co(s) + CO₂(g)   K₂ = 490

We write the first reaction in the forward direction because we need H₂(g) in the reactants side:

(1)     COO(s) + H₂(g) → Co(s) + H₂O(g)    K₁ = 67

Then, we write the second reaction in the reverse direction because we need CO₂(g) in the reactants side. Thus, the equilibrium constant for the reaction in the reverse direction is the reciprocal of the constant for the reaction in the forward direction (K₂):

(2)   Co(s) + CO₂(g) → COO(s) + CO(g)   K₂ = 1/490

From the addition of (1) and (2), we obtain:

COO(s) + H₂(g) → Co(s) + H₂O(g)    K₁ = 67

+

Co(s) + CO₂(g) → COO(s) + CO(g)   K₂ = 1/490

-------------------------------------------------

H₂(g) +  CO₂(g) → CO(g) + H₂O(g)

Notice that Co(s) and COO(s) are removed that appear in the same amount at both sides of the chemical equation.

Now, the equilibrium constant K for the reaction that is the sum of other two reactions is calculated as the product of the equilibrium constants, as follows:

K = K₁ x K₂ = 67 x 1/490 = 67/490 = 0.137

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Answer:

Explanation:

A balanced chemical equation refers to the reaction taking place whereby the number of atoms associated in the reactants side is equivalent to the number of atoms on the products side.

From the given information, the balanced equations are as follows:

[tex]\mathbf{(a) \ \ \ Ti(s) + O_{2(g)} \to TiO_{2(s)}}[/tex]

[tex]\mathbf{(b) \ \ \ 2Ag_{2}O \to 4Ag_{(s)} + O_{2(g)}}[/tex]

[tex]\mathbf{(c) \ \ \ 2C_3H_7OH + 9O_2 \to 6CO_2+8H_2O}[/tex]

[tex]\mathbf{(d) \ \ \ 2C_5 H_{12}O \to 10 CO_2 + 12 H_2O}[/tex]

[tex]\\ \large\sf\longmapsto KNO_3[/tex]

[tex]\\ \large\sf\longmapsto 39u+14u+3(16u)[/tex]

[tex]\\ \large\sf\longmapsto 53u+48u[/tex]

[tex]\\ \large\sf\longmapsto 101u[/tex]

[tex]\\ \large\sf\longmapsto 101g/mol[/tex]

Now

[tex]\boxed{\sf No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}}[/tex]

[tex]\\ \large\sf\longmapsto No\:of\:moles=\dfrac{0.565}{101}[/tex]

[tex]\\ \large\sf\longmapsto No\:of\:moles=0.005mol[/tex]

We know

[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Vol\:of\:Solution\:in\:L}}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{\dfrac{250}{1000}L}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{0.250}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=0.02M[/tex]

[tex] \: \: \: \: \: \: \: \: \: [/tex]

Answer:

5 Br₂ + S₂O₃²⁻ + 5 H₂O ⇒ 10 Br⁻ + 2 SO₄²⁻ + 10 H⁺

Explanation:

We will balance the redox reaction through the ion-electron method.

Step 1: Identify both half-reactions

Reduction: Br₂ ⇒ Br⁻

Oxidation: S₂O₃²⁻ ⇒ SO₄²⁻

Step 2: Perform the mass balance, adding H⁺ and H₂O where appropriate

Br₂ ⇒ 2 Br⁻

5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺

Step 3: Perform the charge balance, adding electrons where appropriate

2 e⁻ + Br₂ ⇒ 2 Br⁻

5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺ + 10 e⁻

Step 4: Make the number of electrons gained and lost equal

5 × (2 e⁻ + Br₂ ⇒ 2 Br⁻)

1 × (5 H₂O + S₂O₃²⁻ ⇒ 2 SO₄²⁻ + 10 H⁺ + 10 e⁻)

Step 5: Add both half-reactions

5 Br₂ + S₂O₃²⁻ + 5 H₂O ⇒ 10 Br⁻ + 2 SO₄²⁻ + 10 H⁺

Kc = [CH4]×[H2O] / [CO]×[H2]^3

Kc = 1.078×0.878 / (0.989×0.933^3)

Kc = 0.977

The numerical value of the equilibrium constant, Kc, for the given reaction is found to be 0.977.

The Equilibrium constant may be defined as the numerical value that significantly indicated the correlation between the amounts of products and reactants present at equilibrium in a reversible chemical reaction at a definite temperature.

According to the question, the reaction is as follows:

[tex]CO +3H_2[/tex] ↔ [tex]CH_4+ H_2O[/tex].

The equilibrium concentrations are 0.989 M, 0.993 M, 1.078 M and 0.878 M, respectively.

Now, the equilibrium constant is calculated by the following formula:

             =  1.078×0.878 / (0.989×0.93[tex]3^3[/tex]).

             = 0.9464/(0.989 × 0.8121)

             =  0.977.

Therefore, the numerical value of the equilibrium constant, Kc, for the given reaction is found to be 0.977.

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