explain why boiling is a reversible change​

Answer:

O-H

Explanation:

It is polar covalent bond, because the hydrogen atom has electronegativity about 2.6, and the oxygen atom, electronegativity about 3.6. When the difference in electronegativity of the atoms is between 0.4 and 1.7, the result is a polar covalent bond.

Answer:

Explanation:

The new pressure can be found by using the formula for Boyle's law which is

[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]P_2 = \frac{125\times3.50 }{2.75} = \frac{437.5}{2.75} \\ = 159.090909...[/tex]

We have the final answer as

Hope this helps you

An observer in one of those galaxies see the other galaxy moving away at 400000 km/s.

Relative velocity is the velocity of an object with respect to another object, that is the time rate of change of relative position of one object with respect to another object.

Since two galaxy are moving in opposite directions with a velocity of 200,000 km/s. Hence the relative velocity between the two galaxies is 400000 km/s (200000 + 200000)

Therefore an observer in one of those galaxies see the other galaxy moving away at 400000 km/s.

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Answer:

D 400,000km/s

Explanation:

The momentum of the bowling ball will be greater than the rest balls.

The correct answer to the question is Option C. The 5 kg bowling ball

Momentum is defined as the product of mass and velocity i.e

Momentum = mass × velocity

If we keep the velocity of the object constant, the momentum will depend on the mass of the object.

Thus, the higher the mass, the greater the momentum and the lesser the mass, the smaller the momentum.

From the question given above,

Mass of tennis = 0.5 Kg

Mass of basketball = 2 Kg

Mass of bowling ball = 5 kg

We can see that the bowling ball has a higher mass.

Therefore, the momentum of the bowling ball will be greater than the rest balls.

The correct answer to the question is Option C. The 5 kg bowling ball

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The orientation of the poles of the magnet on the cars and the large

magnet are like poles.

The correct responses are;

First question

Second question:

Third question:

Fourth question:

Reasons:

Potential energy is the energy an object has due to its location.

Energy is a product of force and distance, and therefore, if the force,

experienced by the object increase, the potential energy of the object

increases.

The strength of a magnetic field, B, is given by the formula;

[tex]\displaystyle B = \frac{\mu_0 \cdot I}{2 \cdot \pi \cdot d}[/tex]

Where;

B = The magnetic field strength

I = Current

d = The distance from the source of the magnet

μ₀ = The permeability of free space = 4·π × 10⁻⁷ T m/A

Therefore, the strength of the magnet is higher closer to the source.

First question

In a magnet, like poles push each other back, and given that the poles of the magnet adjacent to each other are like poles, to get the largest increase in she should move the cars towards the large magnet.

Second question:

The reason why the movement will result in the largest increase in potential energy is because like polls repel each other and the strength of a magnetic field increases closer to the magnet

Third question:

The magnetic force that will act on the roller coaster car moved towards the large magnet, pushes the car in the opposite direction.

Fourth question:

The green cart should be moved from point D to point C to get the largest potential energy

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Answer:

Similar: both processes of cell division; both processes take place in the nucleus of the cell

Different: mitosis divides into 2, meiosis divides into 4; one is the division of body cells and the other is of specifically sex cells

Explanation:

https://byjus.com/biology/mitosis-and-meiosis/

^ this has more info!

Answer:

In chemistry: a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.

Hope this helps :)

Water has relatively strong hydrogen bonds holding the molecules together but CO2 has only dispersion forces acting as intermolecular forces. The weaker intermolecular forces explains why CO2 is a gas whereas H2O is a liquid at room temperature

[tex]2\text{Cr(NO}_3\text{)}_3} + 3\text{CuCl}_2 \longrightarrow 2\text{CrCl}_3 + 3\text{Cu(NO}_3\text{)}_2[/tex]

Answer:

mark me brainlest

Explanation:

Electronegativity values generally increase from left to right across the periodic table. Electronegativities generally decrease from top to bottom of a group. The highest electronegativity value is for fluorine.

Answer:

       "Electronegativity increases as you move from left to right across a period because the number of charges on the nucleus increases." (sstudy30 on Quizlet)

Explanation:

    It explains itself haha!

Have a nice day!

    I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)

- Heather

Answer: 0.023 moles of CaO.

Explanation:

The balanced equation tells us that we'll get 2 moles of CaO for every one mole of O2.  Since we have 0.046 moles of O2, we'll get 0.023 moles of CaO.  (2 sig figs)

Answer:

O b

Explanation:

high compressibility is not the property of metal.

Answer:

Carbon dioxide

Explanation:

Metal oxides are basic and Non metal.oxides are acidic.

Al, Be, Zn,Sn ,Pb oxides are amphoteric so they show both acidic and basic properties.

From the above answers Al, Cu and Mg are metals so their oxides are acidic while Carbon is a non metal.so CO2 is an acidic oxide

Answer: Place a piece of white paper under the analyte flask throughout the titration

Explanation:

The end point of titration can be made easy by the use of indicators. But we have to be keenly observe for each drop from the burette because, the colour change will be sudden for a drop.

Titration is an analytical technique used to determine the unknown concentration using a standard reagent of known concentration. The standard reagent of known concentration is called titrant and the  one to be determined is called analyte.

Usually analyte is taken in a conical flask and titrant in a burette. The end point of titration is the point at which the reaction is completed in perfect stoichiometry.

In acid-base titrations, the indicators used having different colors in different pH. Hence, the indicator in the analyte will change in color when the acidity of the medium changes. We have to observe keenly for the color change because it happens for any drop.

The adding of titrant from the burette must be dropwise and thus we can get a time to notice the sudden colour change of indicator.

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8%

Explanation:

In a DNA molecule the no. of Adenine bases equal to that of Thymine bases

The no. of Cytosine bases equal to that of Guamine bases.

If we take no. of Thymine bases as x and no. of Cytosine bases as y,

Adenine + Thymine + Cytosine + Guamine = 100

x + x + y+y = 100

2( x+y) = 100

x+y = 50

y=42

therefore x= 50-42 = 8%

Answer:

Humans have 23 pairs of chromosomes.

A trisomy is a chromosomal condition characterised by an additional chromosome.

A person with a trisomy has 47 chromosomes instead of 46.

Down syndrome, Edward syndrome and Patau syndrome are the most common forms of trisomy.

Explanation:

In this exercise we want to calculate the amount of moles, so this is going to be:

[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]

Knowing that Henry's law is given by:

[tex]C = KHP[/tex]

Where constants are given by:

Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure.  We look up the vapor pressure of water at 25º and find it to be 0.03 atm.  Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:

[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]

Now using Henry's law, we find the concentration:

[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]

Converting to moles of CO2, we have:

[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]

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Answer:

One arrow is positioned in each box according to Hund's Rule which tells us to maximise the number of unpaired electrons in orbitals of the same subshell, and, to give those electrons the same "spin" (parallel spin).

Explanation:

Answer: 17.7 feet, Its rounded up since the six repeats.

An ionic bond is formed through the transfer of one or more valence electrons, typically from a metal to a non-metal, which produces a cation and an anion that are bound together by an attractive electrostatic force.

Answer:

Explanation:

Pencils are though formed of wood that acts as a bad conductor of electricity, quite strangely pencils can be electrically charged.

Here pencils have non-metal carbons present in its graphite tip and this makes the pencils charged.

When this pencil is held near the water of the tap, the hydrogen ions get attracted and thereby the water gets attracted to the pencil.

Water, however, is an excellent conductor of electricity and therefore water and electricity are a dangerous combination.

[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪  {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]

Metals have tendency to loose electrons in order to get noble gas configuration, therefore they loose electrons to form Cations (positively charged ions)

for example ~ Sodium forms Na+

And

Non - metals have tendency to gain electrons in order to attain noble gas configuration , hence they gain electron from somewhere and bears a negative charge forming Anion.

for example ~ Chlorine forms Cl-

Answer:

Group 17

Explanation:

Group 16 of nonmetals will react with alkaline earth metals to form a compound in a 1 : 1 ratio. Therefore, option (b) is correct.

Alkaline earth metals or Group 2 includes six elements which are Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).

This group contains smooth, silver metals with a less metallic character than group 1.  All alkaline earth metals have two valence electrons, giving a valency of 2. These metals easily lose electrons to form compounds via ionic bonds and become more stable.

The valency of calcium is 2 and the valency of the elements of group 16 is also 2. Therefore they can combine 1 : 1 ratio to form a neutral compound.

Ca²⁺    +   O²⁻   →  CaO

Therefore, the nonmetals of group 16 will react with alkaline earth metal.

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P_4O_8

How?

Let's learn how to create name of compound from its name.

Look below for root words

Hence formula of the compound is P4O8

Answer:

carbohydrates

Explanation:

or carbon dioxide

Explanation:

after learning more about the position and would

Answer:

the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D)

Explanation:

Answer:

The ans is : A. Electron, proton, hydrogen atom, helium atom.

An atom consist of sub atomic particles. The order of particles from least massive to most massive is electron, proton, hydrogen atom, helium atom. The correct option is A.

The particles which are smaller in size than the atom are known as the sub atomic particles. An atom generally contains three sub atomic particles, they are protons, electrons and neutrons. The electrons revolve around the nucleus whereas the protons and neutrons are present at the center of the nucleus.

The protons are positively charged particles whereas the electrons are negatively charged. The neutrons are chargeless. The atomic number of 'H' atom is 1 and that of 'He' atom is 2.

The mass of e⁻ is 9.1 × 10⁻³¹ kg, proton is 1.67 × 10⁻²⁷ kg, 'H' atom is 1.66 × 10⁻²⁴ g, 'He' is 4 g. Thus the order is:

electron, proton, hydrogen atom, helium atom

Thus the correct option is A.

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This problem is referring to an anhydrous salt that is derive from a hydrated Epson salt (magnesium sulfate hydrate) and the atom economy is required. However, not enough information is provided, yet we can use the attached file as a reference to provide a methodology of calculation.

To begin with, we need to calculate the [tex]x[/tex] which refers to the degree of hydration of the salt, so that we use the mass before and after heating the sample to figure out the grams and subsequently moles of water that are in there:

[tex]m_w=3.648g-1.782g=1.866g\\\\n_w=0.103molH_2O[/tex]

Next, since 1.782g corresponds to the anhydrous salt, we calculate the moles in such a amount:

[tex]1.782gMgSO_4*\frac{1molMgSO_4}{120.4gMgSO_4}=0.0148mol[/tex]

Then, we divide the moles of water by those of the anhydrous salt to calculte [tex]x[/tex]:

[tex]x=\frac{0.103mol}{0.0148mol} =6.96=7[/tex]

This means the formula of the hydrate is:

[tex]MgSO_4\ 7H_2O[/tex]

Finally, for the atom economy we just divide the molar mass of the anhydrous salt by that of the hydrate:

[tex]A.E=\frac{120.4g/mol}{246.47g/mol} *100\%\\\\A.E=48.8\%[/tex]

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