84.9 g of solid iron reacts with oxygen gas forming iron(III) oxide. How many moles of oxygen will react

Answer:

Mass Percent of Pencils  =  7.20%

Explanation:

The mass percent can be calculated using the following equation. In this case, the "solute" is the pencil and the "solution" is the collection of pencils.

                               mass solute
Mass Percent  =  ------------------------  x 100%
                              mass solution

                                         9.540 g (pencil)
Mass Percent  =  --------------------------------------------  x 100%
                              132.456 g (pencil collection)

Mass Percent  =  7.20%

Answer:

.129 J / g-C

Explanation:

specific heat =  J / g-°C

                     = 3000 J / ( 465 g  * 50C ) =.129 J /g-C

In a displacement reaction, a more reactive element replaces a less reactive element from a compound. In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.

Explaination:

Displacement chemical reaction :

A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

Fe + CuSO4 → FeSO4 + Cu. When zinc is added to a copper sulphate solution, it displaces the copper metal. ...

Zn + CuSO4 → ZnSO4 + Cu.

etc.

Double Displacement Chemical Reaction :

Double displacement reactions take place mostly in aqueous solutions wherein the ions precipitate and exchange of ions takes place. For example, when a solution of barium chloride is mixed with sodium sulphate, a white precipitate of barium sulphate is formed rapidly. These reactions are ionic in nature.

Here are some examples of double displacement reaction: AgNO 3 + NaCl → AgCl + NaNO.

2NaCl + CaSO4 → Na2SO4+ CaCl.

H2SO4 + 2LiOH ⇌ Li2SO4 + 2H2O.

The correct balanced equation for the dissociation of calcium chloride is [tex]CaCl_2 (s) --- > Ca^{2+} (aq) + 2Cl^- (aq)[/tex]. Option D.

Dissociation in chemistry refers to the process whereby a compound reversibly breaks down to its constituent elements (usually in ion forms) within a solution.

The constituent elements in calcium chloride are calcium and chlorine. Calcium ion is written as [tex]Ca^2^+[/tex] while chlorine ion is written as [tex]Cl^-[/tex]. Calcium chloride itself is written as [tex]CaCl_2[/tex].

Thus, the equation of dissociation of calcium chloride in water can be summarized as:

[tex]CaCl_2 (s) --- > Ca^{2+} (aq) + 2Cl^- (aq)[/tex]

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The equations of reaction occurring in the tubes are as follows:

The reactions occurring in the tubes are redox reactions.

Based on the table the equations of reaction are as follows:

In conclusion, redox reaction are reactions in which electrons are transferred.

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In infrared spectroscopy, absorption of electromagnetic radiation results in transitions between Vibrational energy levels.

Definition of spectroscopy Spectrum analysis is the study and measurement of the spectrum that matter emits when it interacts with electromagnetic (EM) radiation. It is the investigation of how frequency or wavelength affects the relationship between matter and radiation.

The various forms of spectroscopy include the following:

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Answer:

196J, but C. at 200 J comes close.

Explanation:

Potential energy due to gravity is given by:

PEgrav = mass • g • height

where g is the acceleration due to gravity.  We'll use 9.8 N/kg (on Earth).

PEgrav = mass • g • height

PEgrav = (2 kg) • (9.8 N/kg) • (10 m)

PEgrav = 196 N*m

1 N*m = 1 Joule

PEgrav = 196 J

C. at 200 J comes close.  The solution probably used a value of g equal to 10 N/kg)

Answer:

20 J

Explanation:

A symbol of magnesium, Mg, with two dots representing two free electrons. The correct option is D.

Magnesium is represented by Mg.

Magnesium has an atomic number of 12. Thus the electron configuration will be 2,8,2.

This means that there are two valence electrons in every Mg atom.

Therefore, the electron do diagram would be the symbol of the element with two dots representing the two valence electrons.

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Answer:

Two dotted M

Explanation:

Answer:

Atoms gain/lose electrons and are held together by electrostatic forces.

Answer: Iridium

Explanation:

The atomic number of Iridium is 77.

The element we obtain if we remove two protons and two neutrons from the gold is iridium. The atomic number of gold is 79 and that of iridium is 77.

Iridium is the 77th element in the periodic table. It is a transition metal like gold, silver, platinum etc. Iridium is a d-block metal and have its valence electrons in d-orbital.

Gold is 79th element and it is also a transition metal. Gold is a precious metal used in making ornaments and its having high cost.

The atomic number of gold is 79 and it have 79 electrons and 79 protons. The atomic number of an element is the number of its protons and the mass number of the element is the sum of number of electrons and number of protons.

If we remove two protons from the 79 protons of gold the proton number becomes 77 and thus the atomic number. The elements with the atomic number 77 is iridium.

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A student determines the mass of a 100 mL beaker filled with 50 mL of water to be 154.34 grams. After a tablet reacts with the water, the mass including the dissolved tablet is 157.26 grams. 438 grams tablet was left in the beaker after the reaction.

Stoichiometry helps us use the balanced chemical equation to measure quantitative relationships and it is to calculate the amounts of products and reactants that are given in a reaction.

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Now we have to write the balanced chemical equation

NaHCO₃ + H₂O → NaOH + H₂CO₃

Mass = 157.26 - 154.32

         = 2.92

Volume = 100 + 50 ml

             = 150 ml

Mass of tablet = 2.92 × 150

                        = 438 grams  

Thus from the above conclusion we can say that A student determines the mass of a 100 mL beaker filled with 50 mL of water to be 154.34 grams. After a tablet reacts with the water, the mass including the dissolved tablet is 157.26 grams. 438 grams tablet was left in the beaker after the reaction.

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Concentration of hydronium ion is 2.8 x 10⁻¹¹ M.

Given,

[OH⁻] = 3.6 x 10⁻⁴ M                    (concentration of hydroxide ion)

To find,

[H₃O⁺] =?                                     (concentration of hydronium ion)

We know the relation that,

[H₃O⁺] x [OH⁻] = Kw

where,

Kw is the ionic constant of water at 25°C

Kw = 1 x 10⁻¹⁴

Substituting the known concentration of [OH-], we can find the concentration of [H3O+],

[H₃O⁺][3.6 x 10⁻⁴] = 1 x 10⁻¹⁴

[H₃O⁺] = 1 x 10⁻¹⁴/ 3.6 x 10⁻⁴

[H₃O⁺] = 2.8 x 10⁻¹¹ M

Therefore, the concentration of hydronium ion is 2.8 x 10⁻¹¹ M.

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The molar mass of citric acid (c6h8o7) is 192.124g/mol

The molar mass of baking soda (nahco3) is 84.007g/mol

The molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample and is measured in moles. Molar mass is a mass property, not a molecular property of a substance.

Molar mass is the mass of 1 mole of the sample. To find the molar mass, add up the atomic masses (atomic weights) of all the atoms in the molecule. Use the masses listed in the periodic table or atomic weight table to determine the atomic mass of each element.

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The molar mass of citric acid (C6H8O7) : 192.12 g/mol

The molar mass of citric acid (C6H8O7) : 84.007 g/mol

Baking soda is a monosodium salt of carbonic acid with alkalizing and electrolyte substitution properties. When dissociated, baking soda forms sodium and bicarbonate ions. Ion formation increases plasma bicarbonate and buffers excess hydrogen ion concentration, resulting in an increase in blood pH.

Citric acid is a naturally occurring weak acid in all citrus fruits. If you've ever sunk your teeth in a lemon, you've tasted citric acid. Manufacturers add artificial versions of it to processed foods. Drugs containing citric acid treat health problems such as kidney stones.

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Because of the very short period in which nucleosynthesis occurred before it was stopped by expansion and cooling (about 20 minutes), no elements heavier than beryllium (or possibly boron) could be formed.

Big Bang nucleosynthesis occurred inside the first three minutes of the start of the universe and is chargeable for an awful lot of the abundance of H (protium), H (D, deuterium), He (helium-three), and He (helium-4).

Although He remains produced by stellar fusion and alpha decays and hint quantities of H remain produced by way of spallation and certain sorts of radioactive decay, most of the mass of the isotopes inside the universe is thought to be produced in the Big Bang.

The nuclei of these elements, together with a few Li and Be are taken into consideration to have been fashioned between 100 and 300 seconds after the Big Bang whilst the primordial quark-gluon plasma froze out to form protons and neutrons.

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The complete equation representing the synthesis reaction for the formation of ammonia is: 3 H₂ + N₂ ⇒ 2 NH₃

It is a reaction in which 2 or more substances combine to form 1 product.

Let's consider the following incomplete synthesis reaction.

3 H₂ + ____ ⇒ 2 NH₃

According to Lavoisier's law, the mass and the elements must be conserved in a chemical reaction. So, since there is nitrogen to the right, the missing element to the left must be nitrogen. Molecular nitrogen is diatomic.

The complete reaction is:

3 H₂ + N₂ ⇒ 2 NH₃

The complete equation representing the synthesis reaction for the formation of ammonia is: 3 H₂ + N₂ ⇒ 2 NH₃

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The use of cold methanol is important because it is used to recrystallize or solidify the product.

Since, ice bath is also used in nitration of methyl benzoate because in this reaction the concentrated acid like sulfuric acid is used with water and it is very exothermic.

The formation pure solid from the impure solid compound by mixing with hot solvent and form saturated solution. Now, this solution as cools and pure crystal grows when solubility of the compound decreases. This whole process is called re-crystallization.

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Answer: 0.309g

Explanation:

The chemical formula of aluminum chloride is AlCl₃ and the  chemical formula of aluminum oxide is Al₂O₃.

The chemical formula of aluminum chloride is written as;

Al³⁺  + Cl⁻   → AlCl₃

The chemical formula of aluminum oxide is written as;

Al³⁺  + O²⁻   → Al₂O₃

Thus, the chemical formula of aluminum chloride is AlCl₃ and the  chemical formula of aluminum oxide is Al₂O₃.

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Answer:

(a) Gas pressure ---------------------> (iii) force per unit area

(b) One mole of substance -------------------> (i) 6.02 x 10²³

(c) One mole of any gas ----------------------> (ii) 22.4 dm³ at STP

(d) Avogadro's number -----------------> (iv) 6.02 x 10²³ particles

Considering the Charles's law, the volume at 22.8 °C is 10.9978 L.

Charles's law establishes the relationship between the temperature and the volume of a gas when the pressure is constant.

Charles's law says that for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases, and as the temperature decreases, the volume of the gas decreases. That is, the volume is directly proportional to the temperature of the gas.

Mathematically, Charles' law is a law that says that when the amount of gas and pressure remain constant, the ratio between volume and temperature will always have the same value:

[tex]\frac{V}{T} =k[/tex]

Considering an initial state 1 and a final state 2, it is fulfilled:

[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]

In this case, you know that:

Replacing in Charles's law:

[tex]\frac{12 L}{273 K} =\frac{V2}{250.2 K}[/tex]

Solving:

V2= [tex]250.2 K x\frac{12 L}{273 K}[/tex]

V2= 10.9978 L

Finally, the volume at 22.8 °C is 10.9978 L.

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The temperature of an 11.2 L sample of carbon monoxide, CO, at 744 torr is 276 K or 3°C.

Charles's law states that, "When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion".

According to the given information:

V ∝ T

V/T = K

Where,

V is the volume of the gas,

T is the temperature of the gas (measured in kelvins), and

K is a non-zero constant.

In two different states, an initial state 1 and a final state 2, the equation is,

[tex]\frac{V 1}{T 1}=\frac{V 2}{T 2}[/tex]

Given data:

V1 = 11.2L

V2 = 13.3L

T2 = 55°C = 328K

By substituting the given data,

[tex]\begin{aligned}&\frac{11.2}{T 1}=\frac{13.3 L}{328 K} \\&T 1=\frac{11.2 L / 328 K}{13.3 L}\end{aligned}[/tex]

∴T1 = 276K = 3°C

The temperature of an 11.2 L sample of carbon monoxide, CO, at 744 torr is 276 K or 3°C.

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The temperature of an 11.2 L sample of carbon monoxide, CO, at 744 torr is 276 K or 3°C.

What is Charles's law?

Charles's law states that, "When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be in direct proportion".

V ∝ T

[tex]\frac{V}{T}=K[/tex]

Where,

V is the volume of the gas,

T is the temperature of the gas (measured in kelvins), and

K is a non-zero constant.

In two different states, an initial state 1 and a final state 2, the equation is,

[tex]\frac{V1}{T1}=\frac{V2}{T2}[/tex]

Given data:

V1 = 11.2L

V2 = 13.3L

T2 = 55°C = 328K

By substituting the given data,

[tex]\frac{11.2}{T1}=\frac{13.3L}{328K}[/tex]

[tex]T1=\frac{11.2L/328K}{13.3L}[/tex]

∴T1 = 276K = 3°C

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The limiting reactant will be Fe.

They are reactants that are available in limited quantities, as compared to other reactants, during the course of reactions.

From the equation of the reaction: [tex]4Fe + 3O_2 --- > 2Fe_2O_3[/tex]

The mole ratio of Fe to O2 is 4:3.

Thus, for 0.25 mol Fe, 0.25 x 3/4 = 0.1875 mol of O2 is required.

With 0.5 mol of O2 available, it means oxygen is in excess while Fe is limited in availability.

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The limiting reactant from the calculations is Fe.

The limiting reactant is the reactant that is present in the least amount in solution. Now we have the equation as; 4Fe+ 3O2 → 2Fe2O3

If 4 moles of Fe reacts with 3 moles of O2

0.25 mol of Fe  reacts with  0.25 mol *  3 moles/4 moles

= 0.1875 moles of O2

It then follows that the limiting reactant is Fe.

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Answer:

2.46 atm

Explanation:

We are going to use ideal gas law   PV = n RT

find n    mole weight of CO2 = 12.011 + 2 * 15.999 = ~ 44 gm/mole

SO    4.4 gm / 44 gm/mole = .1 mole     (this is 'n' )

R = gas constant = .082057366  L-atm/k-mol

T  must be in Kelvin = 300

PV = nRT

P * 1  = .1 * .082057366 * 300

P = 2.46 atm

To obtain the desired solution:

450 mL of 85% alcohol solution is needed to obtain the desired solution.  

Calculation:

Let x be the amount of the 85% alcohol required

The volume of the resulting 70% alcohol solution will then be = x + 135 ml

135 mL of the 20% alcohol solution contains the amount of "pure" alcohol is =  0.20×135 mL.

The 85% alcohol solution contains x mL of "pure" alcohol = 0.85× x mL.

The total amount of the "pure" alcohol is the sum

=  0.20×135 + 0.85× x mL.

It should be equal to the amount of the "pure" alcohol in the mixture, which is = 0.70× (x+135) ml.

So, your "pure alcohol" equation is,  

=  0.85× x + 0.20×135 = 0.70× (x+135)

Simplify and solve it for x:

0.85x + 0.20×135 = 0.70x + 0.70×135,

0.85x - 0.70x = 0.70×135 - 0.20×135,

0.15x = 67.5

x = 67.5/0.15

= 450mL.

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The Empirical formula of compound is C₁₀H₂₀O₁. The Molecular Formula of compound is C₁₀H₂₀O₁.

Empirical formula is the simplest whole number ratio of atoms present in given compound.

[tex]\text{Mass of C} = 0.2829\ g\ CO_2 \times \frac{12\ g\ C}{44\ g\ CO_2}[/tex]

                = 0.07720 g C

[tex]\text{Mass of H} = 0.1159\ g\ H_2O \times \frac{2\ g\ H}{18\ g\ H_2O}[/tex]

                = 0.01297 g H

Mass of O = Mass of methanol - mass of C - mass of O

                 = 0.1005 g - 0.07720 g - 0.01297 g

                 = 0.01033 g

Element    Mass/g         Moles              Ratio      Integers

C                0.07720       0.006428        9.956      10

H                0.01297        0.01287            19.93      20

O                0.01033        0.0006456       1              1              

The Empirical formula of compound is C₁₀H₂₀O₁.

Molecular formula = Empirical formula × n

[tex]n = \frac{\text{Molar Mass}}{\text{Empirical formula weight}}[/tex]

  [tex]= \frac{156}{156}[/tex]

  = 1

Molecular formula = n × Empirical formula

                               = 1 (C₁₀H₂₀O₁)

                               = C₁₀H₂₀O₁

Thus from the above conclusion we can say that The Empirical formula of compound is C₁₀H₂₀O₁. The Molecular Formula of compound is C₁₀H₂₀O₁.

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Answer:

only one atom of that element

Explanation:

Example:

   H2 O    has two hydrogenatoms and ONE Oxygen atom

The presence of no subscript for an element in a chemical formula means that there is a single atom of that element in the compound.

In a chemical formula, subscripts are used to indicate the number of atoms of each element present in a compound. When an element has no subscript, it means that there is only one atom of that element in the compound.

For example, in the chemical formula H₂O, the subscript 2 indicates that there are two hydrogen atoms present. On the other hand, the absence of a subscript for oxygen means that there is only one oxygen atom in the compound.

Thus, when there is no subscript for an element in a chemical formula, it signifies that there is a single atom of that element in the compound.

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The NaOH will be used What titrant  to titrate the 0. 02 m hcl phenol red solution.

Acid-base titrations may be the most typical titrations, although there are numerous more forms as well. Take a look at this illustration where sodium hydroxide is used to titrate a sample of hydrochloric acid (HCl) (NaOH). The titrant (NaOH), which is added gradually throughout the duration of the titration, has been added to the unknown solution.

Titrants are solutions with known concentrations that are added to solutions whose concentrations must be determined. The solution for whom the concentration needs to be determined is known as a titrant as well as analyte.

Therefore, the NaOH will be used as a titrant to titrate the 0. 02 m hcl phenol red solution.

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According to the ideal gas law, if the volume experienced a small increase, the temperature increases slightly as well. (It has increased slightly.)

It is an equation that relates the pressure (P), volume (V), number of moles (n) and temperature (T) of an ideal gas.

Let's consider the ideal gas law.

P × V = n × R × TA

T = P × V / n × R

According to the expression above, there is a direct relationship between volume and temperature. Thus, if the volume experienced a small increase, the temperature increases slightly as well.

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A. The partial pressure of oxygen in atmospheric air at sea level is greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.

Partial pressure is the pressure exerted by a component of mixture of gases.

The depth (distance from top to bottom) of the atmosphere is greatest at sea level and decreases at higher altitudes.

With greater depth of the atmosphere, more air is pressing down from above.

Air pressure is greatest at sea level and falls with increasing altitude.

Thus, the partial pressure of oxygen in atmospheric air at sea level is greater than the partial pressure of oxygen in atmospheric air at the top of Mt. Everest.

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