How many aluminum atoms are in 2.88 g of aluminum?
Express your answer to three significant figures.

Explanation:

the answer is in the image above

Answer:

A. HCl is the limiting reactant.

B. Theoretical yield of Cl₂ is 20.9 g.

C. Actual yield of Cl₂ = 15.2 g.

Explanation:

The balanced equation for the reaction is given below:

4HCl + MnO₂ –> MnCl₂ + 2H₂O + Cl₂

Next, we shall determine the masses of HCl and MnO₂ that reacted and the mass of Cl₂ produced from the balanced equation. This can be obtained as follow:

Molar mass of HCl = 1 + 35.5

= 36.5 g/mol

Mass of HCl from the balanced equation = 4 × 36.5 = 146 g

Molar mass of MnO₂ = 55 + (2×16)

= 55 + 32

= 87 g/mol

Mass of MnO₂ from the balanced equation = 1 × 87 = 87 g

Molar mass of Cl₂ = 2 × 35.5

= 71 g/mol

Mass of Cl₂ from the balanced equation = 1 × 71 = 71 g

SUMMARY:

From the balanced equation above,

146 g of HCl reacted with 87 g of MnO₂ to produce 71 g of Cl₂.

A. Determination of the limiting reactant.

From the balanced equation above,

146 g of HCl reacted with 87 g of MnO₂.

Therefore, 42.9 g of HCl will react with = (42.9 × 87)/146 = 25.6 g of MnO₂.

From the calculation made above, we can see clearly that only 25.6 g out of 43.1 g of MnO₂ given was needed to react completely with 42.9 g of HCl.

Therefore, HCl is the limiting reactant.

B. Determination of theoretical yield of Cl₂.

Here, the limiting reactant will be used.

From the balanced equation above,

146 g of HCl reacted to produce 71 g of Cl₂.

Therefore, 42.9 g of HCl will react to produce = (42.9 × 71)/146 = 20.9 g of Cl₂.

Thus, the theoretical yield of Cl₂ is 20.9 g.

C. Determination of the actual yield of Cl₂.

Theoretical yield of Cl₂ = 20.9 g

Percentage yield of Cl₂ = 72.9%

Actual yield of Cl₂ =?

Percentage yield = Actual yield / Theoretical yield × 100

72.9% = Actual yield / 20.9

Cross multiply

Actual yield = 72.9% × 20.9

Actual yield = 72.9/100 × 20.9

Actual yield = 0.729 × 20.9

Actual yield of Cl₂ = 15.2 g

Answer:

30 grams of KNO3 can be dissolved.

Explanation:

Hello there!

In this case, since the solubility is defined as the maximum amount of solute that can be dissolved in a certain amount of solvent, usually 100 grams of water as function of the temperature, we will need to recall the graph for the solubility of KNO3 as shown on the attached file.

Thus, by identifying the curve for KNO3, we realize that at a temperature of 20 °C, the solubility is about 30 grams; which means 30 grams can be dissolved in 100 grams of water at 20 °C.

Regards!

Answer:

The product of an organic reaction is analyzed by column chromatography using silica as the stationary phase and toluene as the mobile phase.

Explanation:

The given statement is true.

In chromatography silica gel is used as the predominant stationary phase.

Since silica gel is a good adsorbent.

It is a polar adsorbent.

In order to remove polar components, silica gel is used as the stationary phase.

Answer is a.true.

Answer:

Limiting reagent is the potassium carbonate.

Percent yield of calcium carbonate is: 39.3 %

Explanation:

The reaction is:

CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl

Formula for percent yield is:

(Produced yield / Thoeretical yield) . 100

Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.

1 mol of chloride need 1 mol of carbonate.

14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂

12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.

Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.

Ratio is also 1:1, with calcium carbonate.

1 mol of potassium carbonate produces 1 mol of calcium carbonate

then, 0.0889 moles will produce the same amount of CaCO₃

We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g

That's the theoretical yield; to find the percent yield:

(3.494 g / 8.89g) . 100 = 39.3%

Answer:

Eu(ClO3)3

Explanation:

The chlorate ion is written as follows, ClO⁻ ₃. We can see from this that the ion is univalent.

From the formula, Eu203, it is easy to see that the europium ion is trivalent.

Hence, when a compound is formed between the europium ion and chlorate ion, the compound will be written as Eu(ClO3)3.

This is so because, when ionic compounds are formed, there is an exchange of valence between the ions in the compound. This gives the final formula of the ionic substance.

Answer:

The three primary colors used when mixing dyes or paints are red, yellow, and blue. Other colors are often a mixture of these three colors. Try running a chromatography test again with non-primary-color markers, like purple, brown, and orange.

Explanation:

Answer:

Outermost

Covalent

Two

One

Two

Two

Covalent

One

Explanation:

A covalent bond is formed when an atom shares two electrons with another atom. These shared electrons could be contributed by each of the bonding atoms or by only one of the bonding atoms.

Hydrogen has the electronic configuration of 1s1. This implies that it has only one electron in its valence shell although the 1s shell can accommodate two electrons. When the atomic orbitals of carbon and hydrogen overlap, they share two electrons and hydrogen is now associated with two electrons in a covalent bond.

Since hydrogen possesses only one valence electron, it can not be bonded to two atoms.

Answer: The value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].

Explanation:

pH is the negative logarithm of concentration of hydrogen ion.

It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.

[tex]pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M[/tex]

The relation between pH and pOH value is as follows.

pH + pOH = 14

0.0012 + pOH = 14

pOH = 14 - 0.0012 = 13.99

Now, pOH is the negative logarithm of concentration of hydroxide ions.

Hence, [tex][OH^{-}][/tex] is calculated as follows.

[tex]pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M[/tex]

Thus, we can conclude that the value of [tex][H_{3}O^{+}][/tex] is 0.0012 M and [tex][OH^{-}][/tex] is [tex]1.02 \times 10^{-14}[/tex].

Answer:

37.9% v/v

Explanation:

Since both the alcohol and solution are presumed to be liquid, this concentration can be expressed as a volume concentration (or % v/v):

volume concentration = volume of solute / volume of solution

[tex]\% v/v = 55/145= 0.379[/tex]

Answer:

0.043 grams

Explanation:

We can find the mass of carbon dioxide as follows:

[tex] m = n*M [/tex]

Where:

n: is the number of moles

M: is the molar mass = 44.01 g/mol

First, we need to calculate the number of moles. We can use the Ideal gas equation:

[tex] PV = nRT [/tex]

Where:

P: is the pressure = 0.945 atm

V: is the volume = 25.0 mL  

R: is the gas constant = 0.082 L*atm/(K*mol)

T: is the tempearture = 22.5 °C

[tex]n = \frac{PV}{RT} = \frac{0.945 atm*25 mL*\frac{1 L}{1000 mL}}{0.082 L*atm/K*mol*(22.5 + 273) K} = 9.75 \cdot 10^{-4} moles[/tex]

Hence, the mass is:

[tex]m = 9.75 \cdot 10^{-4} moles*44.01 g/mol = 0.043 g[/tex]

Therefore, 0.043 grams were collected.

I hope it helps you!

Answer:

Concentration of unknown solution is 0.0416 M

Explanation:

As we know  

Absorbance is equal to the product of molar absorptivity of KMnO4 m, path length and concentration

From the given set of graphical data, it is clear that the absorbance vs concentration is a straight line.  

From the graph, we can obtain-  

Y = 5.73 X – 0.0065

Absorbance = 0.232

0.232 = 5.73 X – 0.0065

X = 0.0416  

Concentration of unknown solution is 0.0416 M

Answer:

Ethanal or acetaldehyde

Explanation:

Ethanal, also called acetaldehyde is the second member of the alkanal or aldehyde group of hydrocarbons, which have a functional group of -CHO. The -CHO functional group characterizes every member to this group and makes them behave chemically similar.

However, the second member of this aldehyde group with a formula of CH3----CHO, has a methyl group (CH3) attached to the functional group, hence, it is called ETHANAL OR ACETALDEHYDE.

Answer:

a

Explanation:

Easily broken in chemical reactions

Answer:

Atomic Number. 15=phosphorus

Valency=3

So, Oxide=P203

Answer:

d,e

Explanation:

Answer:

Iodide> Bromide > chloride > flouride

Explanation:

During a nucleophilic substitution reaction, a nucleophilie replaces another in a molecule.

This process may occur via an ionic mechanism (SN1) or via a concerted mechanism (SN2).

In either case, the ease of departure of the leaving group is determined by the nature of the C-X bond. The stronger the C-X bond, the worse the leaving group will be in nucleophilic substitution. The order of strength of C-X bond is F>Cl>Br>I.

Hence, iodine displays the weakest C-X bond strength and it is thus, a very good leaving group in nucleophillic substitution while fluorine displays a very high C-X bond strength hence it is a bad leaving group in nucleophilic substitution.

Therefore, the ease of the use of halide ions as leaving groups follows the trend; Iodide> Bromide > chloride > flouride

Answer:

481.16 cm³

Explanation:

From the question given above, the following data were obtained:

Height (h) = 11.72 cm

Diameter (d) = 7.23 cm

Pi (π) = 3.14159

Volume of cylinder (V) =?

Next, we shall determine the radius. This can be obtained as follow:

Diameter (d) = 7.23 cm

Radius (r) =?

r = d/2

r = 7.23 / 2

r = 3.615 cm

Finally, we shall determine the volume of the cylinder. This can be obtained as shown below:

Height (h) = 11.72 cm

Pi (π) = 3.14159

Radius (r) = 3.615 cm

Volume of cylinder (V) =?

V = πr²h

V = 3.14159 × 3.615² × 11.72

V = 3.14159 × 13.068225 × 11.72

V = 481.16 cm³

Therefore, the volume of the cylinder is 481.16 cm³.

Answer:

The quantity of  heat required to raise the  temperature of 500 g of  iron by 2°C is 500 J.

Explanation:

Calorimetry is responsible for measuring the amount of heat generated or lost in certain physical or chemical processes.

The sensible heat of a body is the amount of heat received or transferred by a body when undergoing a temperature variation (Δt) without there being a change in physical state (solid, liquid or gaseous).

Its mathematical expression is the fundamental equation of calorimetry. This is:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this  case:

Replacing:

Q= 500 [tex]\frac{J}{kg*C}[/tex] *0.500 kg*2 C

Solving:

Q= 500 J

The quantity of  heat required to raise the  temperature of 500 g of  iron by 2°C is 500 J.

Answer:

The mixture is not in equilibrium, the reaction will shift to the left.

Explanation:

Based on the equilibrium:

Fe³⁺+ HSCN ⇄ FeSCN²⁺ + H⁺

kc = 30 = [FeSCN²⁺] [H⁺] / [Fe³⁺] [HSCN]

Where [] are concentrations at equilibrium. The reaction is in equilibrium when  the ratio of concentrations = kc

Q is the same expression than kc but with [] that are not in equilibrium

Replacing:

Q = [10.0M] [1.0M] / [0.1M] [0.1M]

Q = 1000

As Q > kc, the reaction will shift to the left in order to produce Fe³⁺ and HSCN untill Q = Kc

Answer:

2-ethyl-3-methylbut-2-ene

Explanation:

The whole idea of IUPAC nomenclature is to devise a universally accepted system of writing the name of a compound from its structure.

According to IUPAC nomenclature, the root of the compound is the longest carbon chain. The substituents are named in alphabetical order and in such a way as to give each one the lowest number. The position of the functional group is indicated accordingly.

For the compound in question, its correct IUPAC name is 2-ethyl-3-methylbut-2-ene.

Answer:

Explanation:

Let us define oxidation and reduction.

Oxidation and reduction deal with the transferring of electrons between reactants. The reactant that loses electrons is oxidized, while the reactant that gains electrons is reduced.

In an oxidation-reduction reaction, the substance oxidized always loses electrons and the correct option is option D.

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves the transfer of electrons between species. It consists of two half-reactions: an oxidation half-reaction, where a species loses electrons and increases its oxidation state, and a reduction half-reaction, where a species gains electrons and decreases its oxidation state.

In an oxidation half-reaction, the species that is oxidized is called the reducing agent or the electron donor, as it donates electrons. In a reduction half-reaction, the species that is reduced is called the oxidizing agent or the electron acceptor, as it accepts electrons.

Thus, the ideal selection is option D.

Learn more about Oxidation-reduction reactions, here:

https://brainly.com/question/19528268

#SPJ6

Explanation:

pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.

Answer:

Platinum is especially good for this because it is unreactive, and does not produce a color in the flame which will mask the presence of other metals.

Hope this answer is right!

Answer:

Hey mate, here is your answer

1. Platinum doesn't impart any color to the flame.

2. It is not oxidised under the high temperature of the flame from a bunsen burner.

3. It is almost chemically inert. Even at high temperatures, it remains unattacked by free radicals / acid radicals.

Therefore, platinum wire is crucial for a flame test. Also, a platinum wire should be thoroughly cleaned before using it for a new flame test.

A platinum wire is cleaned by dipping it into concentrated HNO3 and then placing it in the non luminous part of the bunsen flame. Otherwise, the perviously tested radicals will impart color to the flame, which may cause confusion.

Explanation:

Hope it helps you

Explanation:

Efficiency = (output/input)×100%

70% = output/(800 W)

which means

output = 0.70×(800 W) = 560 W

Answer:

a it rarely reach with other elements

Answer:

Characteristics of oxygen are as follows:

Answer:

mwlooy kagabi jal

64 JAHA VI PHÂN KAY