A double replacement reaction is a chemical reaction between two ionic compounds in which ions are interchanged to form two new compounds

a. True
b. False

The correct answer is option A; Mesosphere

The mesosphere is defined as the part atmosphere found above the stratosphere but below the thermosphere.

In this layer of the atmosphere, temperature decreases with height. It covers about 50 to 85 km above the earth.

Mesosphere is the only layer of the atmosphere that was correctly spelt among the options.

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Answer:

382mL

Explanation:

Boyle's Law P₁V₁ = P₂V₂

(0.850atm)(675mL) = (1.50atm)(V₂)

573.75 = (1.50atm)(V₂)

V₂ = 573.75/1.50

V₂ = 382.5mL = 382mL

Answer:

78.12 L

Explanation:

Given that,

Initial volume, V₁ = 105 L

Initial temperature, T₁ = 20°C = 20+273 = 293 K

New temperature, T₂ = -55 °C = 218 K

We need to find the new volume of the balloon. The relation between the volume and the temperature is given by :

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

Where

V₂ is the new volume

[tex]V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{105\times 218}{293}\\\\V_2=78.12\ L[/tex]

So, the new volume is 78.12 L.

Answer:

11 electrons

Explanation:

The number of electrons is the same as the number of protona in a ATOM.

They will most likely be different in a ion, simple bond or a convalent bond.

B. cryolite substance produces sulfur dioxide when roasted in air.

Cryolite (Na3AlF6, sodium hexafluoroaluminate) is an uncommon mineral identified with the once-large deposit at Ivittuut on the west coast of Greenland, mined commercially until 1987.

Sulfur dioxide (SO2) is a gaseous air pollutant composed of sulfur and oxygen. SO2 forms when sulfur-containing fuel such as coal, oil, or diesel is burned. Sulfur dioxide also converts in the atmosphere to sulfates, a major part of fine particle pollution in the eastern U.S.

Sulfur dioxide (SO2), a colorless, bad-smelling, toxic gas, is part of a larger group of chemicals referred to as sulfur oxides (SOx). These gases, especially SO2, are emitted by the burning of fossil fuels — coal, oil, and diesel — or other materials that contain sulfur.

Although its chief uses are in the preparation of sulfuric acid, sulfur trioxide, and sulfites, sulfur dioxide also is used as a disinfectant, a refrigerant, a reducing agent, a bleach, and a food preservative, especially in dried fruits.

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Written Answer: Covalent bonds hold atoms together in molecules and polyatomic ions where as intermolecular forces hold molecules together in a liquid or solid. Intermolecular forces are generally much weaker than covalent bonds.

Explanation/Evidence: "In contrast to intramolecular forces, such as the covalent bonds that hold atoms together in molecules and polyatomic ions, intermolecular forces hold molecules together in a liquid or solid. Intermolecular forces are generally much weaker than covalent bonds."

Answer:

Ca²⁺(aq) + S²⁺(aq) + Cd²⁺(aq) + 2Cl¯(aq) —> CdS (s) + Ca²⁺(aq) + 2Cl¯(aq)

Explanation:

CaS (aq) + CdCl₂ (aq) –> CdS (s) + CaCl₂ (aq)

The complete ionic equation for the above reaction can be obtained as illustrated below:

In solution:

CaS (aq) —> Ca²⁺(aq) + S²⁺(aq)

CdCl₂ (aq) —> Cd²⁺(aq) + 2Cl¯(aq)

CaS (aq) + CdCl₂ (aq) –>

Ca²⁺(aq) + S²⁺(aq) + Cd²⁺(aq) + 2Cl¯(aq) —> CdS (s) + Ca²⁺(aq) + 2Cl¯(aq)

Answer:

114.23g

Explanation:

Mass = xg

Mole = 0.334 mol

Molar mass of Sucrose

(C = 12, H = 1, O = 16)

C12H22O11

(12×12)+(1×22)+(16×11)

144 + 22 + 176

342g/mol

Mass = No of mole × Molar mass

Mass = 0.334 × 342

Mass = 114.228

Mass ≈ 114.23g

Answer:

750 mmHg

Explanation:

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

Partial pressure of CO₂ (Pₐ) = 250 mmHg

Partial pressure of N₂ (P₆) = 375 mmHg

Partial pressure of He (P꜀) = 125 mmHg

Pressure of the mixture (Pₜ) =?

The pressure of the mixture of the gases can be obtained as follow:

Pₜ = Pₐ + P₆ + P꜀

Pₜ = 250 + 375 + 125

Pₜ = 750 mmHg

Therefore, the pressure of the mixture of the gases is 750 mmHg

Answer:

6.80×10¯²⁶ J

Explanation:

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

Frequency (f) = 102.5 MHz

Energy (E) =?

Next, we shall convert 102.5 MHz to Hz. This can be obtained as follow:

1 MHz = 10⁶ Hz

Therefore,

102.5 MHz = 102.5 MHz × 10⁶ Hz / 1 MHz

102.5 MHz = 1.025×10⁸ Hz

Finally, we shall determine the energy. This can be obtained as follow:

Frequency (f) = 1.025×10⁸ Hz

Planck's constant (h) = 6.63×10¯³⁴ Js

Energy (E) =?

E = hf

E = 1.025×10⁸ × 6.63×10¯³⁴

E = 6.80×10¯²⁶ J

Answer: The hydrogen ion concentration in molarity is 0.013

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pOH is calculated by taking negative logarithm of hydroxide ion concentration and pH is calculated by taking negative logarithm of hydrogen ion concentration

Putting in the values:

[tex]pOH=-\log[7.609\times 10^{-13}][/tex]

[tex]pOH=12.1[/tex]

Now , [tex]pH+pOH=14[/tex]

[tex]pH=14-12.1=1.9[/tex]

[tex]pH=-\log [H^+][/tex]

[tex][H^+]=0.013M[/tex]

The hydrogen ion concentration in molarity is 0.013

Answer:

The most abundant chemical/gas is Nitrogen, which makes up about 78% and Oxygen at second place with approximately 21%

Answer:

Nitrogen and Oxygen because about 70% of air is nitrogen and around 20% of air is Oxygen.

Hope this helps!

it can occur 5 atoms

Explanation:

that is base on my study

Answer:

c. core, mantle and atmosphere

Answer:

Correct answer is letter A

Because Lithosphere includes the crust and the uppermost mantle.

Answer:

Atomic theory is the scientific theory that matter is composed of particles called atoms. Atomic theory traces its origins to an ancient philosophical tradition known as atomism. ... An atom is now defined as the basic particle that composes a chemical element.

Explanation:

Hope i helped

Answer:

the water molecules have more energy and are moving faster than the molecules of cold water. This makes it easier for the dye to get mixed throughout the hot water.

Explanation:

Answer:

Because particles moves more by kinetic energy and diffusion will spread with the particles

Explanation:

Answer❣

The required speech is as follows :

_______________

"Whoever controls media, controls mind". A very hearty Good Morning to one and all present here ! Respected Principal Sir, worthy teachers and all my dear fellow mates. Today I Aurora, of class XYZ is standing before you in this frizzy winter to deliver a short speech on the topic 'How media influences public opinion'.

Dear friends, first of all I would like to ask you all a question, 'What do you think is our media for ?' Most of us will reply that they are for our entertainment, fun and even unfortunately some will reply 'for movies and Bollywood'. Now if we look back at our history during 18th century we see that even first newspapers were started for spreading information in mass. Earlier literacy rate of India was very low.

A single person used to first read the newspaper and then shared the information to the gathered people around. But that time was different. Now nearly every person has a mobile phone, TV, PC and what not. Has this increased public participation in Democracy ? Yes indeed it has done that. On one single click we get information of our surrounding at a faster pace. As a fourth pillar of Democracy it makes our mindful of different social, political and financial exercises around us.

If we take current situation, most of the election popularisation works in different states is being managed by mass media only due to its advancements. Media makes participation of people in political activities even at grass - root levels. This efficiency enhances the Federalism of India. Media has many roles in shaping public opinion in our society. Let's discuss them one by one. In economic terms, media shows the expenditure, budgets and taxes to the citizens of a nation.

It makes people aware of the different types of money related issues that they have to face. Even it checks that no people are harassed by fake news on balances. Its makes people rise over their concern directly to the government so that actions can be taken for them. In social terms, media promotes the functioning of the government. It helps people to convey their social problems to the government. Even many NGOs and Human Rights Organizations take help of medias to make people aware of their rights.

Commonly Media acts as an inference or better to say 'compass' which gives direction to the views of people. It organises the vast multitudes of opinions into a single issue which can be beneficial to all the groups of society. It works 24 × 7 and makes people get in touch with latest developments. As 'Opposition' in Politics, media acts as a hub where the opposition party by taking views of public claims the wrong decisions of Ruling Party.

Also, during elections media shows mirror about different parties to people so that we can make right decision in voting. All these were some positive aspects of media's influence on public opinions. Now let's discuss about some negative aspects also. Nowadays its a common seen trend that media enlarges a short issue just to gain popularity. This results in riots, violence, protests, etc. because the issue which could have been solved by a single subtle discussion, now has been made a larger issue.

Let me present an example. I have a friend, Cupicake. She remains quite much familiar with medias. Some days ago, she received a post which asked her to share the image attached with it to her other friends. That image was of a case where Police was beating a few groups of people. She has shared that. This led a immediate violence in that region and finally it was known that Police was beating a few robbers. Now who to put blame of that riot ? Of course we are the one who done it.

At last I would like to conclude my speech by just saying that, it is the duty of media to transfer right and reliable information to people and its duty of people to share and trust upon right information from a good source. In this way the world and the nation would be leaded to right path.

Thank you one and all.

_______________

★ More to know :-

Format of Speech :

*Note - Here I used name as Aurora. You can use any according to your choice and class also according to the situation.

✌✌✌✌✌✌✌✌✌✌✌✌

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the answer is A..which is true

Answer:

true

Explanation:

Answer:

13 branches/tree

Explanation:

Step 1: Given data

Step 2: Calculate the total number of branches (b)

We will use the following expression.

b = l × b/l

b = 19565 leaves × 1 branch/35 leaves = 559 branch

Step 3: Calculate the number of branches per tree (b/t)

We will divide the total number of branches by the total number of trees.

559 branches/43 trees = 13 branches/tree

Answer:

The part of the skull surrounding the brain grew larger as hominins evolved

The skulls are all casts of the original fossils. By determining the skulls we can explore the characteristics which reflect the evolutionary relationships. The part of the skull surrounding the brain grew larger as hominins evolved. The correct option is C.

Hominin evolution is characterized by two mains trends, transition to bipedality and increase in brain size. Fossil evidence shows that both trends had a major impact on the structure and function of the hominin skull.

Hominins or homo species are characterized by relatively and absolutely large brains, a modern skeleton, reduced tooth and jaw size and an involvement in cultural activities. Hominins have a larger cranial capacity and this is an indication of their brain size.

In addition, the contour of the hominin forehead eventually shifted from being angled to more vertical.

Thus the correct option is C.

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Answer:

23.92 g

Explanation:

Molar mass of H2SO4 = (2×1)+32+(16×4)= 2+32+48= 82g/mol

H2SO4 + 2NaOH ---> Na2SO4 + 2H2O

I mole of H2SO4 = 2 moles of NaOH

24.5/82 = 24.5/82 × 2

= 0.598 moles of NaOH will neutralize

Mass= mole× molar mass

Molar mass of NaOH= 23+16+1 = 40g/mol

Mass= 0.598 × 40 = 23.92g of NaOH

Answer:

20g

Explanation:

First of all, you have got your formula wrong. It should be [tex]H_{2}SO_{4} + 2NaOH = Na_{2}SO_{4} + 2H_{2}O[/tex].

Start by finding the Relative Formula Mass for sulfuric acid. [tex]H_{2}SO_{4}[/tex] is equal to (2x1)+32+(16x4)=98. You then calculate Mols by doing [tex]Mols=\frac{Mass}{Relative Formula Mass}[/tex]. So, [tex]\frac{24.5}{98} = 0.25[/tex], so the Mols of Sulfuric Acid is 0.25.

The Mol ratio of Sulfuric Acid to Sodium Hydroxide is 1:2, so 0.25:0.5.

Now, you have to find the Relative Formula Mass of Sodium Hydroxide, or [tex]NaOH[/tex]. 23+16+1=40. Finally, multiply 0.5 by 40, and you'll find that the maximum mass is 20g.

Answer:

sp3 - 1,2,13,16,18,19

sp2- 3,4,5,6,7,8,9,10,11,12,14,15,17

sp- 0

Explanation:

Hybridization is the idea that atomic orbitals fuse to form newly hybridized orbitals, which in turn, influences molecular geometry and bonding properties (Chemlibretexts).

Carbon atoms that are singly bonded are sp3 hybridized, carbon atoms that are doubly bonded are sp2 hybridized while carbon atoms that are triply bonded are sp hybridized.

Sp3 hybridized atoms have a tetrahedral geometry, sp2 hybridized atoms have a trigonal planar geometry while an sp hybridized atom has a linear geometry.

The hybridization state of each atom in the compound has been shown in the answer section.

Answer:

292.4 g

Explanation:

First we convert 53.7 g of Al into moles, using its molar mass:

Then we convert Al moles into H₂SO₄ moles, using the stoichiometric coefficients:

Finally we convert 2.98 moles of sulfuric acid into grams, using its molar mass:

Answer:

It is not water absorbant and also the colour black, due to it's dark nature makes the person wearing the cloth feel hot. Unlike cotton, silk is not at all water absorbant as it does not absord any sweat produced in the wearers body

Answer:we see 1 side because the other side is not visible

Explanation: