what is the main idea of the article, "Great Wall of China"?

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Answer 1

well, without the article, I'm guessing the main idea is about the Great Wall of China


Related Questions

what is Lfusion in the equation Q=mLfusion

Answers

Answer:

[tex]L_{\text{fusion}[/tex] is latent heat of fusion.

Explanation:

Latent heat is basically termed as hidden heat. It is defined as the amount of heat required to change 1 g of a substance at the temperature of its melting point from the solid to the liquid state at constant temperature.The formula that relates heat and latent heat of fusion is given by :

[tex]Q=mL_{\text{fusion}}[/tex]

Here,

m is mass of substance

[tex]L_{\text{fusion}[/tex] is latent heat of fusion.

Consider an electrochemical cell based on the spontaneous reaction 2AgCl(s) + Zn(s) → 2Ag(s) + 2Cl– + Zn2+. If the zinc ion concentration is kept constant at 1 M, and the chlorine ion concentration is decreased from 1 M to 0.001 M, the cell voltage should:

Answers

Answer:

there is an increase by 0.18 V in the cell voltage.

Explanation:

The given equation of the reaction can be well written as

[tex]2AgCl_{(s)} + Zn _{(s)} \to 2Ag_{(s)} + 2 Cl^- _{(aq)}+ Zn^{2+}_{(aq)}[/tex]

By application of Nernst Equation ; we have the expression

[tex]E_{cell} = E^0- \dfrac{0,059}{n}log (\dfrac{[product]}{[reactant]})[/tex]

here in the above equation;

n = number of electrons transferred in the equation of the reaction

n = 2

Also;

[tex]E^0 = E_{cathode} - E_{anode}[/tex]

[tex]E^0 = E_{Ag^+/Ag} - E_{Zn^+/Zn}[/tex]

[tex]E^0 = +(0.80 \ V) - (-0..76 \ V)[/tex]

[tex]E^0 = (0.80 \ V +0..76 \ V)[/tex]

[tex]E^0 = 1.56 \ V[/tex]

If the zinc ion concentration is kept constant at 1 M; we have:

[tex]E_{cell} = E^0- \dfrac{0.059}{n}log (\dfrac{[product]}{[reactant]})[/tex]

[tex]E_{cell} = 1.56 - \dfrac{0.059}{2}log ({[Zn^{2+} ]}{[Cl^{2-}]})[/tex]

[tex]E_{cell} = 1.56 - \dfrac{0.059}{2}log (1)[/tex]

Since log(1) = 0

Therefore;

[tex]E_{cell} = 1.56\ V[/tex]

When the chlorine ion concentration is decreased from 1 M to 0.001 M; we have;

[tex]E_{cell} = E^0- \dfrac{0.059}{n}log (\dfrac{[product]}{[reactant]})[/tex]

[tex]E_{cell} = 1.56 - \dfrac{0.059}{2}log ({[Zn^{2+} ]}{[Cl^{2-}]})[/tex]

[tex]E_{cell} = 1.56 - \dfrac{0.059}{2}log ({[1*0.001^2}]})[/tex]

[tex]E_{cell} = 1.56 - 0.0295 \ * \ log ({[1*10^{-6}}]})[/tex]

[tex]E_{cell} = + 1.737 \ V[/tex]

The change in voltage = [tex]E_{cell} - E^0[/tex]

=( 1.737 - 1.56 )V

= 0.177 V

≅ 0.18 V

Thus; from the following observation; there is an increase by 0.18 V in the cell voltage.

The voltage of the cell increased by 0.18 V.

The equation of the reaction is; 2AgCl(s) + Zn(s) → 2Ag(s) + 2Cl– + Zn2+

We know that;

E°cell = 1.36 - (-0.76) = 2.12 V

If the cells are both at 1M concentration the Ecell = E°cell = 2.12 V

When the concentration of Cl- decreased from 1 M to 0.001 M

Ecell =  E°cell - 0.0592/n log Q

Substituting values;

Ecell = 2.12 V -  0.0592/2 log (1 × (0.001)^2)

Ecell = 2.298 V

Increase in voltage = 2.298 V - 2.12 V = 0.18 V

Learn more: https://brainly.com/question/165414

what is the mass of 1.5 mol of aluminum?

Answers

Answer:

40.47 g Al

Explanation:

In 1 mol of Al, there are 26.98 grams of Al, so Al is 26.98 g/mol.

Simply multiply 1.5 by 26.98 to get your answer.

Which refers to the density of the medium’s particles at the compression of a sound wave? A.amplitude B.pitch C.volume D.wavelength

Answers

Answer:

A is the answer.

Explanation:

The sound wave is a longitudinal wave which travels in the form of compression and rarefaction . The point where the particles are closer to each other is called compression and the point where the particles are far apart from each other is called rarefaction.

Answer:

Amplitude

Explanation:

Amplitude describes the displacement of the medium's particles. The higher the amplitude, the more dense it is, and the lower the amplitude, the less dense it is.

Pitch is incorrect because it describes the sound

Volume is incorrect because it describes the sound.

Wavelength is incorrect because it describes the distance between a period of a wave.

name the bleaching agent for cloth​

Answers

Hydrogen peroxide is one of the most common bleaching agents. It is the primary bleaching agent in the textile industry, and is also used in pulp, paper, and home laundry applications.

bleaching agent is a material that lightens or whitens a substrate through chemical reaction. The bleaching reactions usually involve oxidative or reductive processes that degrade color systems. These processes may involve the destruction or modification of chromophoric groups in the substrate as well as the degradation of color bodies into smaller, more soluble units that are more easily removed in the bleaching process. The most common bleaching agents generally fall into two categories: chlorine and its related compounds (such as sodium hypochlorite) and the peroxygen bleaching agents, such as hydrogen peroxide and sodium perborate. Reducing bleaches represent another category. Enzymes are a new category of bleaching agents. They are used for textile, paper, and pulp bleaching as well as for home laundering. Chlorine‐containing bleaching agents are the most cost‐effective bleaching agents known. They are also effective disinfectants, and water disinfection is often the largest use of many chlorine‐containing bleaching agents. They may be divided into four classes: chlorine, hypochlorites, N‐chloro compounds, and chlorine dioxide. Except to bleach wood pulp and flour, chlorine itself is rarely used as a bleaching agent. The principal form of hypochlorite produced is sodium hypochlorite. Other hypochlorites include calcium hypochlorite and bleach liquor, bleaching powder and tropical bleach. The principal solid chlorine bleaching agents are the chlorinated isocyanurates, eg, sodium dichloroisocyanurate dihydrate. Other N‐chloro compounds include halogenated hydantoins, and sodium N‐chlorobenzenesulfonamide (chloramine B). Chlorine dioxide is a gas that is more hazardous than chlorine. Large amounts for pulp bleaching are made by several processes in which sodium chlorate is reduced with chloride, methanol, or sulfur dioxide in highly acidic solutions by complex reactions. Hydrogen peroxide is one of the most common bleaching agents. It is the primary bleaching agent in the textile industry, and is also used in pulp, paper, and home laundry applications. Hydrogen peroxide reacts with many compounds, such as borates, carbonates, pyrophosphates, sulfates, etc, to give peroxy compounds or peroxyhydrates. Peracids have superior cold water bleaching capability versus hydrogen peroxide because of the greater electrophilicity of the peracid peroxygen moiety. Lower wash temperatures and phosphate reductions or bans in detergent systems account for the recent utilization and vast literature of peracids in textile bleaching. The reducing agents generally used in bleaching include sulfur dioxide, sulfurous acid, bisulfites, sulfites, hydrosulfite (dithionites), sodium sulfoxylate formaldehyde, and sodium borohydride. These materials are used mainly in pulp and textile bleaching.

ANSWER:
Hydrogen peroxide is one of the bleaching agents that is most commonly used worldwide.
HOPE IT HELPS!!!

how many atoms are contained in 2.70g of aluminum provided that 32g of sulphur equals 6.02 × 10^(23)atoms​

Answers

Answer:

[tex]1.63 \times {10}^{24} [/tex]

one atom of an element = 6.02 \times {10}^{23} atom

The mass of one atom of sulphur = 32g

The mass of one atom of aluminium = 27g

so one atom of aluminium = 6.02 \times {10}^{23}

27g of AL = 6.02 \times {10}^{23} atom

2.70g of AL = X atoms

Then you cross multiply ........

and get the answer

.

Primary succession is most likely caused by?

Answers

Answer:

volcanic eruption.

mark my answer as brainlest......

what is meant by amoeba and what is the name of its parts​

Answers

Answer:

amoeba is the unicellular organism which can be seen by only microscope but not with our nacked eyes

Answer:

An amoeba often called an amoeboid, is a type of cell or unicellular organism which has the ability to alter its shape, primarily by extending and retracting pseudopods Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.

name of parts of ameoba

3 parts – the cytoplasm, plasma membrane and the nucleus. The cytoplasm can be differentiated into 2 layers – the outer ectoplasm and the inner endoplasm. The plasma membrane is a very thin, double-layered membrane composed of protein and lipid molecule

i hope this will help you

Which consists of only one type of atom?

Answers

Answer:

A chemical element

Explanation:

A chemical element consists of only one type of atom.

How does the government control scientific research

Answers

Answer:

The government allocates a budget for research every year. The spending of that money is determined by government priorities. Some of the money is spent directly, in government-funded research centers.

Other money is distributed to other research institutions.

Money spent by other institutions for research has no government oversight.

Explanation:

Calculate the payback time if she insulates the loft with 300 mm insulation when: area of loft space = 100m^2 cost of roll of 100 mm thick loft insulation that covers 8.3m^2 = £20 cost of putting the insulation into the loft = £120 savings per year = £80 per 100 mm Payback Time = installation cost divided by annual savings

Answers

Answer: Payback time = 0.0075

Explanation: Since payback time is calculated as:

payback time = [tex]\frac{installation cost}{annual savings}[/tex]

First determine the installation cost:

100 mm thick insulation covers 8.3 m². Then 300 mm covers 24.9 m².

To cover 8.3m² costs £20. Then, the cost to cover 24.9 m² is:

cost = [tex]\frac{20*24.9}{8.3}[/tex]

cost = £60

The cost of putting the insulation is £120, so the total cost is:

total cost = £60 + £120

total cost = £180

Savings per year per 100 mm thick is £80. For 300 mm, the value of annual savings is:

savings = [tex]\frac{300*80}{100}[/tex]

savings = 240

payback time = [tex]\frac{installation cost}{annual savings}[/tex]

payback time = [tex]\frac{180}{240}[/tex]

payback time = 0.75

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