Helpppp
Which of these is the BEST
description of extinction?

Answer:

A

Explanation:

Answer:

B hotplate beakers thermometers

Explanation:

Answer:yea im going to go with A

Explanation:

Answer:

CaSO4. 2H2O

Explanation:

mass of  hydrated salt = 10 g

mass of anhydrous salt = 7.90 g

molar mass of hydrated salt = 136 + 18x g/mol

molar mass of anhydrous salt = 136 g/mol

mass of  hydrated salt/molar mass of hydrated salt = mass of anhydrous salt/molar mass of anhydrous salt

10.0/136 + 18x = 7.90/136

136 * 10 = 7.90 (136 + 18x)

1360 = 1074.4 + 142.2x

1360 - 1074.4 = 142.2x

285.6 = 142.2x

x = 285.6 /  142.2

x = 2

Hence the empirical formula of the compound is CaSO4. 2H2O

Answer:

if you mean group 4a then it is a metalliod

Explanation:

The SI unit of volume is the cubic meter.

Explanation:

During condensation reaction, two molecules combine to form a single molecule with the loss of a small molecule; in dehydration reaction, this lost molecule is water.

The reaction is a small molecule formed from the atoms removed from a single reactant molecule this reaction is knowing as condensation reaction.

Essentially, this is the reverse process of vaporization. In order for water vapor to undergo the process of condensation, which is the change from a gaseous state to a liquid state, it is necessary for a reduction in its temperature to occur until it reaches the dew point or an increase in the pressure to which it is subjected.

In this case the condensation reaction are when two molecules combine to form a single molecule with the loss of a small molecule, in dehydration reaction, this lost molecule is water.

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Answer:

Ne

Explanation:

Neon is the element with the most stable outer electron configuration because it has eight valence electrons that fill the outer shell. Eight electrons in the outer shell is the most stable arrangement of electrons. Neon is also a noble gas which means that due to it already having a complete outer shell, it doesn't lose, gain, or share electrons. Therefore, it is stable.

Hope that helps.

Answer:

I assume you mean as in elements

A metal "A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile." (wiki)

a non-metal "In chemistry, a nonmetal is a chemical element that mostly lacks the characteristics of a metal. Physically, a nonmetal tends to have a relatively low melting point, boiling point, and density. A nonmetal is typically brittle when solid and usually has poor thermal conductivity and electrical conductivity." (wiki)

Explanation:

Answer:

On the periodic table, the metals are usually on the left and middle side and nonmetals on the right side. nonmetals tend to be either a liquid or gas at room temperature and metals are usually solids at room temperature.

Explanation:

Answer:

You can test whether or not the object is more or less dense than what by having, “80mL” (as long as the amount of water is easy to read and doesn’t overflow). You take all the object you want to test for, slowly and carefully drop the object into the water. If the Object sinks it is more dese and if it floats it is less dense. To find the exact density of the tested objects look at how much water is being displaced in the container and subtract the amount of water from that to get volume. Then, (or before putting the object into water) weight the object to find its mass. Next you divide the mass in mL by the volume to get the exact density.

Explanation:

Answer:

constant

Explanation:

A constant is a number with a fixed value in a specific mathematical context

Answer: The answer is  C

Explanation: And  coordinate them with a rectangle or square tiles to provide constant.

Answer:

1) eathquake

earthquake is the natural calamities where there is the vertical and horizontal shaking of the

earth crust. it is cause due to overlappibg of the different plates that are present in the earth surface. when this plates intersect or expand the earth occurs

consequences are it causes loss of life and human property , degards the environment , it leads to flood, landslides etc The damage caused by earthquakes is from ground shaking, ground rupture, landslides, tsunamis, and liquefaction.

Next - volcanic eruption

its is the out flow of the larva from the inner of the earth to other surface. it is cayse due to high pressure exerted on the surface of the earth that leads to explode the inner larva.

its consequences are it degards the environment and loss of the beauty of the nature , there is loss of human life , widlife , etc. volcanic eruption include infectious disease, respiratory illness, burns, injuries from falls, and vehicle accidents related to the slippery, hazy conditions caused by ash. When warnings are heeded, the chances of adverse health effects from a volcanic eruption are very low.

Answer:

Explanation:

V/t

Answer:

they have two valence electrons

Explanation:

They readily give up their two valence electrons to achieve a full outer energy level, which is the most stable arrangement of electrons

Answer: you should use the platform desmos to help you if you put in all the information it will give you the graph then you can just copy it on to your graph.

Explanation:

Answer:

See the answer below

Explanation:

A scientist B might want to replicate the experiment of another scientist A in order to assess the claims made by scientist A. In other words, replication of the experiment of another scientist is done to see if a similar outcome would be arrived at or there would be variations.

The claims made by a scientist while reporting the outcome of a particular experiment must be reproducible by another scientist under similar conditions. Otherwise, the claims are said to be false.

Answer: The answer is 1/4

Explanation:

Therefore, the fraction of an original sample of tritium that remains unchanged after 24.62 years will be 1/4.

A fraction denotes a portion of something larger or, more broadly, any quantity of equal pieces.

Calculation of fraction

Given data:

t = 24.62 years = 25 years.

T = 12.5 years

Fraction can be calculated by using the formula:

N / [tex]N_{0}[/tex] = (1/2) power n..................(i)

n = t / T,......(ii)

Put the value of t and T in fraction equation.

n = 25 / 12.5

n = approx = 2.

Now, using equation (ii).

N / [tex]N_{0}[/tex] = (1/2) power 2

N / [tex]N_{0}[/tex]  = 1/4.

Therefore, the fraction of an original sample of tritium that remains unchanged after 24.62 years will be 1/4.

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Answer:

Explanation:

.......

Answer:

Gas

Explanation:

Solid= Particles are really tight (Example: Ice Cube) Has a fixed shape

Liquid= Particles flow freely but is of constant volume.(Liquid fills it's container. Example: Water) No fixed shape

Gas= Particles move freely can fill its container has NO FIXED SHAPE or NO FIXED VOLUME(Example: Oxygen) Particels move FASTEST

Answer:

D on Edge2021

Explanation:

trust me bro

The temperature of 0.750 mol of a gas stored in a 6,850 mL cylinder at 2.21 atm will be 245.9K. Hence, Option (D) i.e, 246 K  is correct. It can be solved with the help of Ideal gas equation.

The ideal gas equation is formulated as: PV = nRT.

In the above equation, P refers to the pressure of the ideal gas, V is the volume of the ideal gas, n is the total amount of ideal gas that is measured in terms of moles, R is the universal gas constant, and T is the temperature.

Given ,

From,

PV=nRT

T = (2.21×6.85) ÷ (0.750×0.0821)

T = 245.9K  i.e,  246 K approx

Therefore, The temperature of 0.750 mol of a gas stored in a 6,850 mL cylinder at 2.21 atm will be 245.9K. Hence, Option (D) i.e, 246 K  is correct.

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Answer:

e,b and d

Explanation:

Answer:

a,b,d,e

Explanation:

getting 20 characters longgggggggggbs o i can do thisssss

when hydrogen peroxide mixed with vinegar makes peracetic which is potentially toxic and irritate skin, eyes and respiratory system.

Answer:

1- Using buses rather than opting for cars.

2- Regularly servicing your cars.

Explanation:

The Lewis structure shows electron pairs in bonds between the atoms and the solitary electron pairs that remain for each atom. (a) in attached files, (b) the formal charge on N is the same +3, (c) NO₂⁻ exhibits resonance  

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Nitrous acid molecule, HNO₂

N has 5 electrons

H has 1 electron

O has 6 electrons

There are two single bonds between H, O, and N

There is one double bond between N and the other O

Each bond represents two electrons

Excepting H, the other elements need to have eight electrons in total.

5 eletrons from N + 1 eletron from H + 12 electrons from the two O = 18 e⁻

18 e⁻ = 9 pairs or electrons

The two simple bonds + the double bond represent 4 electron pairs. So, there are still 5 electron pairs to place.

One of the O forms two single bonds, so it already has 2 pairs of electrons. It needs two more pairs to get the 8e⁻. So 4 electrons are placed arround this O.

The other O forms a double bond with N. The double bond represents 4 electrons. So this O needs another 4 electrons to get to the octet. Two pairs are placed arround this atom.

N forms a single bond with one O and a double bond with another O, so it already has 6 electrons. It only needs 2 more electrons to get to the octet. One pair is placed over the atom.

Finally H does not need to get any other electron

Nitrite ion, NO₂⁻

N has 5 electrons

O has 6 electrons

And there is a free negative charge, e⁻

There is one single bond between one of the O, and N

There is one double bond between N and the other O

The double bond is composed of a  single bond and a resonant bond

Each bond represents two electrons

5 eletrons from N + 12 electrons from the two O + 1e⁻ = 18 e⁻

18 e⁻ = 9 pairs or electrons

The single bonds + the double bond represent 3 electron pairs. So, there are still 6 electron pairs to place.

One of the O forms one single bond, so it already has 2 electrons. It needs three more pairs to get the 8e⁻. So 6 electrons are placed arround this O.

The other O forms a double bond with N. The double bond represents 4 electrons. So this O needs another 4 electrons to get to the octet. Two pairs are placed arround this atom.

N forms a single bond with one O and a double bond with another O, so it already has 6 electrons. It only needs 2 more electrons to get to the octet. One pair is placed over the atom.      

b) The formal charge on N (= +3) is the same for both species  

The formal charges refer to the partial charges of each atom that are shared with another atom. It is the difference between the total valence electrons (8), the electrons that are not in the bond (2), and half the shared electrons (3).    

formal charge on N = 8 - 2 - 3 = +3

c) Since nitrite ion, NO2- is the only one that exhibits a symetrical structure, it is the only one expected to show resonance.

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Answer:

1 is the answer of these questions

Alkali metals are extremely reactive because they 3. have one valence electron that is easily removed to form a positive ion

The alkali metals are the elements in group 1 of the periodic table. They are lithium, sodium, potassium, rubidium, cesium, and francium. These elements are all very reactive because they have one valence electron that is easily removed to form a positive ion.

The valence electron is the electron that is furthest away from the nucleus of the atom. It is also the electron that is involved in chemical bonding. The alkali metals have a very low ionization energy, which means that it does not take much energy to remove the valence electron.

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Answer:

Mercury chemical bond with aluminum, AKA aluminum amalgam

Explanation:

After the protective oxide layer on aluminum is broken, if mercury were to come into contact with it, then the aluminum will bond with the mercury and will create this interesting tower looking thing upwards. You can learn more about this by searching up Aluminium amalgam, where there is plenty of info about it.

Answer:

8 moles

Explanation:

Al reacts with [tex]S_8[/tex] to produce [tex]Al_2S_3[/tex] as

[tex]Al+S_8\rightarrow Al_2S_3[/tex]

The balanced chemical equation is

[tex]16Al+3S_8\rightarrow 8Al_2S_3[/tex]

In the reaction, 16 moles of [tex]Al[/tex] react with 3 moles of [tex]S_8[/tex] to produce 8 moles of [tex]Al_2S_3[/tex].