Select the atomic models that
belong to the same element.

Answer:

Pollen

Explanation:

Pollen is a powdery substance consisting of pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells).

Answer:

d

Explanation:

answer d makes the equation balance

Answer:

Fractional distillation of crude oil in laboratory

Explanation:

In general, we can sort them according to their boiling point.

We should first place a ball of mineral wool soaked with petroleum into a boiling tube and heat it with a Bunsen flame. At the beginning of the experiment, heat the mineral with a gentle flame, and then more strongly later. The fraction with a lower boiling range will distil out first. Since petrol is quite volatile, it should be condensed by cooling with water or an ice-water bath.

Petrol will be collected first, as it has a lower boiling point than kerosene. It will turn into vapour and condense again in the receive tub in the beaker.

The equilibrium concentration of N₂O₄, given that the concentration of NO₂ is 1.78×10⁻² is 5.42×10⁻²

Keq = [Product] / [Reactant]

Keq = [NO₂]² / [N₂O₄]

5.85×10⁻³ = [1.78×10⁻²]² / [N₂O₄]

Cross multiply

5.85×10⁻³ × [N₂O₄] = [1.78×10⁻²]²

Divide both sides by 5.85×10⁻³

[N₂O₄] = [1.78×10⁻²]² / 5.85×10⁻³

[N₂O₄] = 5.42×10⁻²

Learn more about equilibrium constant:

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Answer:

First answer is "The equilibrium lies to the left", and the second one is 5.42 x 10^-2 M.

Explanation:

Hope i helped yall :D

Answer:

standard sea- level pressure,by definition,equals 760 mm of Mercury,14.70 pounds per square inch, 1,013.25x10³ dynes per square centimetre, 1,013.25 millibars,one standard atmosphere,or 101.325 kilopascale

l hope it's helpful for u....

Answer:

The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

Explanation:

There will be a transfer of thermal energy (heat) from the hot metal plate to the surrounding air. This transfer of energy equates to a transfer of kinetic energy in the molecules. As the plate loses heat, the molecules in the plate will lose kinetic energy and slow down. As the surrounding air gains heat, the molecules will gain kinetic energy and speed up.

Answer: C

Explanation:

Answer:

a

Explanation:

dont have to explain

Answer:

Explanation:

Mass of uncrystallized product = (Mass of watch glass + filter paper + crystallized product) - (Mass of watch glass + filter paper)  

Mass of uncreystaliized product = 109.03 gm - 105.98 gm

Mass of uncrystaliized product = 3.05 gm

For methyl benzoate;

mass = 3.08 g

no of moles = 3.08 g/ 136.15 g/mol = 0.0226 mole

It is possible for the formation of 1 mole of nitro methyl benzoate from a mole of methyl benzoate.

moles of nitro methyl benzoate that can be formed from 0.0226 moles of methyl benzoate = 0.0226 moles

∴

mass of nitro methyl benzoate = 0.0226 mol × 181.15 gm /mol

mass of nitro methyl benzoate = 4.098 gm

For HNO_3 solution:

mass = 1.42 gm/ml × 2.0 ml

mass = 2.84 gm

Mass of HNO3 in 2.84 gm solution[tex](69\% w/w)= 2.84 gm * \dfrac{69}{100 }[/tex]

= 1.9596 gm

Moles of HNO3 = [tex]\dfrac{ 1.9596 \ gm }{ 63.01 gm /mol}[/tex]

= 0.0311 mole

1 mol of HNO_3 can be formed from 1 mole of nitro methyl benzoate

Thus; moles of nitro methyl benzoate that can be formed from 0.0311 mole of HNO_3 = 0.02256 mole

The mass for nitro methyl benzoate can now be determined as:

= 0.0311 mole × 181.5 gm/mole

= 5.634 gm

Since the mass formed from methyl benzoate is lesser, then methyl benzoate serves as the limiting reagent.

The mass obtainable from the LR = 4.098 gm

Answer:

Explanation:

The standard molar mass is:

For (S )-1-chloro-4-ethyl-2-methylhexane = 162.5 g/mol

For triphenylphosphine  = 262 g/mol

For  ( S )-1-chloro-4-ethyl-2-methyl triphenylphosphonium = 424.5 g/mol

The mass required for 81% yield = [tex]\dfrac{81}{100} \times Theoretical \ yield = 4.15 g[/tex]

Theoretical yield = [tex]\dfrac{4.15}{0.81}[/tex]

= 5.1235 g

thus, since 424.5 g yield produce from 162.5 g

∴

5.1235 g yield will produce = [tex]\dfrac{162.5}{424.5}\times 5.1235 \ g[/tex]

= 1.9613 g of alkyl halide (-chloro) required.

Also, since 424.5 g yield produce from 262 g phosphine

∴

5.1235 g yield will produce = [tex]\dfrac{262}{424.5}\times 5.1235 \ g[/tex]

= 3.1622 g of triphenylphosphine required.

Answer:

According to the Brønsted definition, an acid is a substance capable of donating a proton, and a base is a substance capable of accepting a proton. ... The species giving up the proton is HCl, an acid. The species accepting the proton is water, the base. The species Cl- is the conjugate base of HCl.

Answer:

write the balanced chemical equation of the reaction between strong acid and weak base also mention the types of salt obtained in the reaction

Explanation:

HCl → H+(aq) + Cl−(aq) (100%)

Any acid that dissociates 100% into ions is called a strong acid. If it does not dissociate 100%, it is a weak acid. HC2H3O2 is an example of a weak acid:

HC2H3O2→ H+(aq) + C2H3O2−(aq) (~5%)

Because this reaction does not go 100% to completion, it is more appropriate to write it as an equilibrium:

HC2H3O2 ⇄ H+(aq) + C2H3O2−(aq)

As it turns out, there are very few strong acids, which are given in Table 12.2 “Strong Acids and Bases”. If an acid is not listed here, it is a weak acid. It may be 1% ionized or 99% ionized, but it is still classified as a weak acid.

Answer: frequency is 8.57 ·10^14 Hz

Explanation: lambda = 3500 A = 0,000 000 350 m

Wave number is 1/ lambda = 2857142.857 1/m

Wave equation c = frequency · lambda and f = c / lambda

Frequency = 300 000 000 m/s / 0,000 000350 m

The wavelength number is [tex]2.85\times 10^{6}\ m^{-1}[/tex] and the frequency is [tex]8.57\times 10^{14}\ Hz[/tex].

Explanation:

Given that,

The wavelength of violet radiation,

[tex]\lambda=3500\ A\\\\=3500\times 10^{-10}\ m\\\\=3.5\times 10^{-7}\ m[/tex]

To find,

The wave number and frequency of violet radiation.

Solution,

Wavelength, [tex]\lambda=3.5\times 10^{-7}\ m[/tex]

Wave number is the reciprocal of the wavelength,

[tex]\overline{\lambda}=\dfrac{1}{\lambda}[/tex]

Put all the values,

[tex]\overline{\lambda}=\dfrac{1}{3.5\times 10^{-7}}\\\\\overline{\lambda}=2.85\times 10^{6}\ m^{-1}[/tex]

The relation between the wavelength, frequency and speed of wave is given by :

[tex]f=\dfrac{c}{\lambda}[/tex]

Where

c is the speed of light

Put all the values,

[tex]f=\dfrac{3\times 10^8}{3.5\times 10^{-7}}\\\\f=8.57\times 10^{14}\ Hz[/tex]

So, the wavelength number is [tex]2.85\times 10^{6}\ m^{-1}[/tex] and the frequency is [tex]8.57\times 10^{14}\ Hz[/tex].

Reference,

https://brainly.com/question/22721527

Answer:

Pka of formic acid (HCOOH)= 3.75

pH= PKa +log [ Sodium formate/ formic acid] = 3.75

NaOH reacts with HCOOH as HCOOH (aq) + NaOH(aq) --> NaCHO2 (aq) and H2O (l)

Moles of HCOOH= 0.1*1= 0.1 moles

Moles of NaOH= 5*1/1000= 0.005 moles

HCOOH is in excess and the excess is = 0.1 - 0.005 = 0.095

Moles of sodium formate = 0.005 + 0.1 = 0.105 moles of HCOOH= 0.095

volume after mixing = 1 + 5 /1 000=1.005

Concentrations : HCOOH= 0.095/1.005 sodium formate= 0.105/1.005

pH= 3.75+log (0.105/0.095)=3.85

When NaOH is added, molarity is , 1*5= 1000*M

M= 5/1000=0.005

The pH remains the same. Only the molarity of NaOH changes.

Answer:

Explanation:

In electrophilic aromatic substitution, the substituent(s) that favors electrophilic attack is said to be ortho or para to the substituent. Meta directors are deactivators. Altogether, these directors have an integral role to play in the success and regioselectivity of electrophilic aromatic substitution reactions.

From the information given: The;

Strongly deactivating meta- director  ⇒ NO₂ (nitro group)

Moderately deactivating meta- director  ⇒ CN (cyano group)

Strongly activating ortho-/para- director ⇒ OH (hydroxy; group)

Weakly deactivating ortho-/para- director ⇒ -X (halide group)

Weakly activating ortho-/para- director ⇒ - Ph  (phenyl group)

Ortho and para substituents favors the electrophilic substitution reaction and meta substituents are deactivators.

Regioselectivity of any reaction tells about the preferred side over another side of the reaction to success.

Ortho or para substituents on the benzene ring will increase the chances of electrophilic aromatic substitution by increase the s electrons on the ring. While the meta directors are deactivators, they have an integral role to play in the success and regioselectivity of electrophilic aromatic substitution reactions.

Strongly deactivating meta director nitro group.

Moderately deactivating meta director cyano group.

Strongly activating ortho/para director hydroxy group.

Weakly deactivating ortho/para director halide group.

Weakly activating ortho/para director phenyl group.

Hence, from the above discussion it is clear that Ortho and para substituents favors the electrophilic substitution reaction and meta substituents are deactivators.

To know more about regioselectivity, visit he below link:

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Answer:

The peritoneum

Explanation:

The peritoneum is the serous membrane that surrounds several organs in the abdominopelvic cavity. The tunica vaginalis is the serous membrane, which surrounds the male gonad, the testis. The two layers of serous membranes are named parietal and visceral. Between the two layers is a thin fluid filled space.

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Answer:

[tex]\Large \boxed{\sf -6000 \ J}[/tex]

Explanation:

Use formula

[tex]\displaystyle \sf Heat \ (J)=mass \ (kg) \times specific \ heat \ capacity \ (Jkg^{-1}\°C^{-1}) \times change \ in \ temperature \ (\°C)[/tex]

Specific heat capacity of ice is 2,000 J/(kg °C)

Substitute the values in formula and evaluate

[tex]\displaystyle \sf Heat \ (J)=0.05 \ kg \times 2000 \ Jkg^{-1}\°C^{-1} \times (-100\°C-(-40 \°C))[/tex]

[tex]Q=0.05 \times 2000 \times (-100-(-40)) =-6000[/tex]

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1) 2KCIO3=2kci+3o2

2)CH4 + 2O2 → CO2 + 2H2O

3)  2HCl + Ca(OH)2 → CaCl2 + 2H2O

I hope this helped!

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Answer:

Explanation:

When two non-miscible liquids are put together, the one with the higher density will be on the bottom, while the one with the lower density will be on top.

Meaning that in this problem's case toluene would be on the top layer and water in the bottom layer.

Answer:

m=2.0mol/kg

Explanation:

Hello there!

In this case, according to the formula to compute molality, which requires moles of solute (HCl) and kilograms of solvent (water), we first compute the moles of the former with its molar mass as shown below:

[tex]n=\frac{18.2g}{36.46g/mol}= 0.50mol[/tex]

And then the kilograms of water:

[tex]\frac{250.g}{1000g/kg} =0.250kg[/tex]

Finally, the molality turns out to be:

[tex]m=\frac{0.50mol}{0.250kg}\\\\m=2.0mol/kg[/tex]

Best regards!

Answer:

It depends. what hot spot are you looking for?

Answer:

A hot spot is an area on Earth over a mantle plume or an area under the rocky outer layer of Earth, called the crust, where magma is hotter than surrounding magma. The magma plume causes melting and thinning of the rocky crust and widespread volcanic activity.

Explanation:

Hope this is what you mean be hot spot!

I hope this helps you!  

Answer:

2Zn2+3O2 ----> 2ZnO+2SO2

Explanation:

Answer:

Download Ptable, it will show all of the elements, and you can click on them, and it will show all the information you need about them!

Explanation:

I hope this helps!!!!!

Answer:

pH = 5.85

Explanation:

The reaction of methylamine with HCl is:

CH₃NH₂ + HCl → CH₃NH₃⁺ + Cl⁻

As the titration was made with two solutions with the same molarity, the final concentration of the CH₃NH₃⁺ ion is 0.100M ([CH₃NH₃⁺] = 0.100M)

Then, the conjugate acid will be in equilibrium with water as follows:

CH₃NH₃⁺(aq) + H₂O(l) ⇄ CH₃NH₂(aq) + H₃O⁺(aq)

And the equilibrium constant, Ka, of this reaction is:

Kw/Kb = Ka =  1.0x10⁻¹⁴ / 5.0x10⁻⁴= 2x10⁻¹¹

2x10⁻¹¹ =  [CH₃NH₂] [H₃O⁺] / [CH₃NH₃⁺]

As both CH₃NH₂ and H₃O⁺ comes from the same equilibrium we can say:

[CH₃NH₂] = [H₃O⁺] = X

And as we know [CH₃NH₃⁺] = 0.100M:

2x10⁻¹¹ =  [X] [X] / [0.100M]

2x10⁻¹² = X²

X = 1.414x10⁻⁶M = [H₃O⁺]

And as pH= -log [H₃O⁺]

Answer:

[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]

Explanation:

Hello there!

In this case, when coming across combustion reactions whereby hydrocarbons as fuels are burnt in the presence of oxygen, the main products are said to be carbon dioxide and water in agreement to the breaking and rearrangement of bonds due to the collisions among molecules. Thus, for the reaction between propane and oxygen we have the following balanced reaction:

[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]

Best regards!

Answer:

3.25 moles of H2O

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

2HCl + Ca(OH)2 —> CaCl2 +2H2O

Now, we can obtain the number of mole H2O produced from the reaction as follow:

From the balanced equation above,

2 moles of HCl reacted to produce 2 moles of H2O.

Therefore, 3.25 moles of HCl will also react to produce 3.25 moles of H2O.

Therefore, 3.25 moles of H2O were produced from the reaction.