A student puts a glass of water in the freezer. Later, he notices ice forming on the surface of the water. Which property of water best explains why ice forms on its surface? A. It is made of polar molecules. B. It has low surface tension. C. It has weak adhesion. D. It is densest as a solid.

Answer:

It is a combustion reaction.

Answer:

2,3 Dimethyl hexane

Explanation:

First, start the count from which side is given the CH3 smallest number

first; the longest carbon chain in this compound is 6

and you don't have any double and triple bonds or functional groups so it is Hexane

you start to count from the right side to give the branch molecules the smallest number ..

CH3 = methyl

and you have 2 methyl in this compound ..

and 2 mean you must write ( Di )

you write the name in this way

2,3 Dimethyl hexane

hope this helps you.

stay safe ...

Answer:

an increase in 1-butene was observed when t-butoxide was used

Explanation:

When a base reacts with an alkyl halide, an elimination product is formed. This reaction is an E2 reaction.

Here we are to compare the reaction of two different bases with one substrate; 2-bromobutane. Both reactions occur by the E2 mechanism but follow different transition states due to the size of the base.

The Saytzeff product, 2-butene, is obtained when the methoxide is used while the non Saytzeff product, 1-butene, is obtained when t-butoxide is used.

The Saytzeff rule is reliable in predicting the major products of simple elimination reactions of alkyl halides given the fact that a small/strong bases is used for the elimination reaction. Therefore hydroxide, methoxide and ethoxide bases give similar results for the same alkyl halide substrate. Bulky bases such as tert-butoxide tend to yield a higher percentage of the non Saytzeff product and this is usually attributed to steric hindrance.

Answer:

[tex]91°C[/tex]

Explanation:

CHECK THE COMPLETE QUESTION BELOW;

Suppose that 0.95 g of water condenses on a 75.0 g block of iron that is initially at 22 °c. if the heat released during condensation is used only to warm the iron block, what is the final temperature (in °c) of the iron block? (assume a constant enthalpy of vaporization for water of 44.0 kj/mol.)

Heat capacity which is the amount of heat required to raise the temperature of an object or a substance by one degree

From the question, it was said that that 0.95 g of water condenses on the block thenwe know that Heat evolved during condensation is equal to the heat absorbed by iron block.

Then number of moles =given mass/ molecular mass

Molecular mass of water= 18 g/mol

Given mass= 0.95 g

( 0.95 g/18 g/mol)

= 0.053 moles

Then Heat evolved during condensation = moles of water x Latent heat of vaporization

Q= heat absorbed or released

H=enthalpy of vaporization for water

n= number of moles

Q=nΔH

Q = 0.053 moles x 44.0 kJ/mol

= 2.322 Kj

=2322J

We can now calculate Heat gained by Iron block

Q = mCΔT

m = mass of substance

c = specific heat capacity

=change in temperature

m = 75 g

c = 0.450 J/g/°C

If we substitute into the above formula we have

Q= 75 x 0.450 x ΔT

2322 = 75 x 0.450 x ΔT

ΔT = 68.8°C

Since we know the difference in temperature, we can calculate the final temperature

ΔT = T2 - T1

T1= Initial temperature = 22°C

T2= final temperature

ΔT= change in temperature

T2 = T1+ ΔT

= 68.8 + 22

= 90.8 °C

=91°C

Therefore, final temperature is [tex]91°C[/tex]

The final temperature of the iron block is 91∘C.

Given that;

Heat lost during condensation of the water = Heat gained by iron block

Mass of water(mw) = 0.95 g

Latent heat of vaporization =  Latent heat of condensation(L) = 44.0 kJ/mol

Mass of iron(mi) = 75.0 g

Initial temperature of iron(T1) =  22∘C

Final temperature of iron(T2) = ?

Heat capacity of iron(ci) =  0.449 J⋅g−1⋅∘C−1

So;

mwL = mici(T2 - T1)

Substituting values;

(0.95g/18g/mol) ×  44.0 × 10^3(J/mol) = 75.0(g) × 0.449 J⋅g−1⋅∘C−1 (T2 - 22∘C)

2322.2 = 33.7T2 - 741.4

2322.2 +  741.4 = 37.4T2

T2 = (2322.2 +  741.4)/ 33.7

T2 =91∘C

Missing parts;

Suppose that 0.95 g of water condenses on a 75.0 g block of iron that is initially at 22 °c. if the heat released during condensation is used only to warm the iron block, what is the final temperature (in °c) of the iron block? (assume a constant enthalpy of vaporization for water of 44.0 kj/mol.)

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Answer:

Anaxagoras was perhaps the first literate person to attempt to explain physical phenomena rationally, basing his ideas upon careful observations and simple experiments. This is fundamental to modern science and is the sine qua non of environmental study.

Answer:

OPTION C is correct

3.86 x 10-19 J

Explanation:

Energy of the line can be calculated using below formula

E= h ν.................(1)

Where E= energy

h= plank constant= 6.626 10-34 J s

c=speed of light=3 x 108 m/s

But we know that Velocity V= = c / λ

Then substitute into equation (1) we have

E = h c / λ.............(2)

We can calculate our( hc ) in nm for unit consistency

h c =( 6.626 ×10^-34)x(3×108)

h c = (1.986 x 10-16 )

hc = 1.986 x 10-16 J nm then since our (hc) and λ are in the same unit , were good to go then substitute into equation(2)

E = h c / λ = (1.986 x 10-16) / 515

E = 3.86 x 10-19 J

Therefore, the Energy is 3.86 x 10-19 J

Answer:

b) the Ka of NH₄⁺ to find the hydronium concentration

Explanation:

The equilbrium of NH₄⁺ (The conjugate acid of NH₃, a weak base), is:

NH₄⁺ ⇄ NH₃ + H⁺

Where Ka of the conjugate acid is:

Ka = [NH₃] [H⁺] / [NH₄⁺]

Thus, if you know Ka of NH₄⁺ and its molar concentration you can calculate  [H⁺], the hydronium concentration, to find pH (Because pH =  -log [H⁺])

Thus, right option is:

Answer: The calculated molar enthalpy change of reaction for his second trial was -108 kJ.

Explanation:-

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

[tex]\text{no of moles}={\text{Molarity}\times {\text{Volume in L}}[/tex]

Thus [tex]\text{no of moles}of HCl={1.0M}\times {0.05L}=0.05moles[/tex]

Thus [tex]\text{no of moles}of NaOH={1.0M}\times {0.05L}=0.05moles[/tex]

[tex]HCl(aq)+NaOH(aq)\rightarrow NaCl(aq)+H_2O(l)[/tex]

Given for second trial:

[tex]\text{no of moles}of HCl={1.0M}\times {0.1L}=0.1moles[/tex]

[tex]\text{no of moles}of NaOH={1.0M}\times {0.1L}=0.1moles[/tex]

0.05 moles of [tex]HCl[/tex] reacts with 0.05 moles of [tex]NaOH[/tex] to release  heat = 54 kJ

0.1 moles of [tex]HCl[/tex] reacts with 0.05 moles of [tex]NaOH[/tex] to release  heat  =[tex]\frac{54}{0.05}\times 0.1=108kJ[/tex]

Thus calculated molar enthalpy change of reaction for his second trial was -108 kJ.

Answer:

Since the relationship between amino acid and codon bases would be the values of 3 nitrogenous bases per 1 amino acid.

knowing this relationship what you would do is simply multiply 146 x 3 to find the number of codon bases which would be C. 438.

A strand of messenger RNA coding the synthesis of a protein with 146 amino acids must have a string of 438 bases along its backbone and the correct option is option C.

mRNA or messenger RNA is a single stranded RNA molecule. It is complementary to the DNA and carries genetic information present in the DNA. It is translated to form proteins. The genetic codes (triplet) present on mRNA get translated to amino acids, giving rise to the functional product of a gene.

So mRNA really is a form of nucleic acid, which helps the human genome which is coded in DNA to be read by the cellular machinery. mRNA is actually the translated form of DNA that the machinery can recognize and use to assemble amino acids into proteins.

Each strand has 3 bases, so 146 × 3 = 438 bases

Therefore, A strand of messenger RNA coding the synthesis of a protein with 146 amino acids must have a string of 438 bases along its backbone and the correct option is option C.

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Answer:

The pH of the solution will be 3

Explanation:

The strength of acids is determined by their ability to dissociate into ions in aqueous solution. A strong acid is any compound capable of completely and irreversibly releasing protons or hydrogen ions, H⁺. That is, an acid is said to be strong if it is fully dissociated into hydrogen ions and anions in solution.

Being pH=- log [H⁺] or pH= - log [H₃O⁺] and being a strong acid, all the HClO₃ dissociates:

HClO₄      +    H₂O        →      H₃O⁺      +      ClO₄-  

So: [HCLO₄]= [H₃O⁺]

The molar concentration is:

[tex]molar concentration=\frac{number of moles of solute}{volume solution}[/tex]

The molar mass of HClO₄ being 100 g / mole, then if 100 grams of the compound are present in 1 mole, 0.025 grams in how many moles are present?

[tex]moles of HClO_{4} =\frac{0.025 grams*1 mole}{100 grams}[/tex]

moles of HClO₄= 0.00025

Then:

[tex][HClO_{4}]=\frac{0.00025 moles}{0.25 L}[/tex]

[tex][HClO_{4}]=0.001 \frac{ moles}{ L}[/tex]

Being [HCLO₄]= [H₃O⁺]:

pH= - log 0.001

pH= 3

The pH of the solution will be 3

Answer:

SCN- is a weak field ligand while CN- is a strong field ligand

Explanation:

The spectrochemical series is an arrangement of ligands according to their magnitude of crystal field splitting. Ligands that cause only a small degree of crystal field splitting are called weak field ligands while ligands that cause large crystal field splitting are called strong field ligands.

Strong field ligands often lead to the formation of low spin complexes with the least number of unpaired electrons while high spin complexes are formed by weak field ligands.

CN- is a strong field ligand as it lies towards the right hand side of the spectrochemical series.

SCN- is a weak field ligand hence it forms a high spin complex having the maximum number of unpaired electrons for Fe^3+, hence the answer.

SCN⁻ lies in the lower (weak field) region of the spectrochemical series while CN⁻ lies in the higher (stronger field) region.

CN⁻ is a strong field ligand with a large splitting constant, and it is high up in the spectrochemical series.

Conversely, SCN⁻ is a weak field ligand with a low splitting constant, and it is lower in the spectrochemical series.

Hence, SCN⁻ lies in the lower (weak field) region of the spectrochemical series while CN⁻ lies in the higher (stronger field) region.

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The given question is incomplete. The complete question is:

Compound X has a molar mass of 153.05 g/mol and the following composition:

element mass %

carbon 47.09%

hydrogen 6.59%

chlorine 46.33%

Write the molecular formula of X.

Answer: The molecular formula of X is [tex]C_6H_{10}Cl_2[/tex]

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C= 47.09 g

Mass of H = 6.59 g

Mass of Cl = 46.33 g

Step 1 : convert given masses into moles.

Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{47.09g}{12g/mole}=3.92moles[/tex]

Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{6.59g}{1g/mole}=6.59moles[/tex]

Moles of Cl =[tex]\frac{\text{ given mass of Cl}}{\text{ molar mass of Cl}}= \frac{46.33g}{35.5g/mole}=1.30moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = [tex]\frac{3.92}{1.30}=3[/tex]

For H = [tex]\frac{6.59}{1.30}=5[/tex]

For Cl =[tex]\frac{1.30}{1.30}=1[/tex]

The ratio of C : H: Cl= 3: 5 :1

Hence the empirical formula is [tex]C_3H_5Cl[/tex]

The empirical weight of [tex]C_3H_5Cl[/tex] = 3(12)+5(1)+1(35.5)= 76.5g.

The molecular weight = 153.05 g/mole

Now we have to calculate the molecular formula.

[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{153.05}{76.5}=2[/tex]

The molecular formula will be=[tex]2\times C_3H_5Cl=C_6H_{10}Cl_2[/tex]

Answer:

A

Explanation:

The lithosphere represents the layer of hardened/solid rock that makes up the hard part of the earth, including the brittle upper portion of the mantle and the crust. The lithosphere is broken into pieces that are referred to as plates. The pieces move to and away from each other in a process known as plate tectonics. The movement of plates accounts for the global locations of volcanoes, earthquakes, and mountain ranges.

The lithosphere is made of largely of inorganic materials known as silicates. The weathering of the solid rocks together with the interaction of living organisms gives rise to soil with an appreciable amount of organic materials.

The correct option is, therefore A.

a)

HSO₃⁻ + OH⁻ → H₂SO₄⁽²⁻⁾

In this reaction, we know that OH will act as a base. which means that the bisulfite ion will act as an acid

also because SO₃⁽²⁻⁾ will be relative more stable than O⁽²⁻⁾ because of larger valence shell. so HSO₃ will protonate. making it the acid

b)

HSO₃⁻ + H₃O⁺ → H₂SO₃

Here, the hydronium ion will be the one to protonate because that will help it form water, which is a much stabler compound

so the hydronium ion will protonate, making it the acid and the bisulfite will take that proton, making it the base

Answer:

plz mark as BRAINLIEST plz...

Explanation:

●Intellectual factor: The term refers to the individual mental level. ...

●Learning factors: ...

●Physical factors: ...

●Mental factors: ...

Answer:

Explanation:

MnO₂(s) + 4 HCl(aq)  = MnCl₂(aq) + 2 H₂O(l) + Cl₂

87 g                                                                     22.4 x 10³ mL

volume of given chlorine gas at NTP or at 760 Torr and 273 K

=  175 x ( 273 + 25 ) x 715 / (273 x 760 )

= 179.71 mL

22.4 x 10³ mL of chlorine requires 87 g of MnO₂

179.4 mL of chlorine will require    87 x 179.4 / 22.4 x 10³ g

= 696.77 x 10⁻³ g

= 696.77 mg .

Answer: [tex]Rate=k[A][B][/tex]

Explanation:

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.

For reactions which takes place in multiple steps are complex reactions and the order is given by the slowest step which is the rate limiting step.

For the given reaction, the rate limiting step is

[tex]A+B\rightarrow D[/tex]

Rate law will be , [tex]Rate=k[A][B][/tex]

Answer:

Siδ⁺ -- Pδ⁻⁻

Clδ⁻⁻ -- Pδ⁺

Siδ⁺ -- Clδ⁻⁻

Of the mentioned bonds the most polar bond is Si -- Cl

The polarity of the bond primarily relies upon the electronegativity difference between the two atoms that forms the bond. Therefore, if the electronegativity difference between the two atoms that forms the bond is more the bond will be more polar, and if it is less then the bond will be less polar. The electronegativity of the atoms mentioned is Si = 1.8 , P = 2.1 and Cl = 3.00.  

Therefore, the Si - Cl atoms exhibit more electronegativity difference, thus, the Si - Cl bond will be the most polar bond.  

Answer:

d) Solid water

Explanation:

because it's particles are more fixed together ( least apart ), so their mobility and conductivity is very low hence lowest kinetic energy.

Answer:

d. Solid water

Explanation:

example ice

Answer:

C. 0.191 M

Explanation:

Our goal for this question, is to calculate the concentration of the HCl solution. For this, in the experiment, a solution of NaOH was used to find the moles of HCl. Therefore, our first step is to know the reaction between HCl and NaOH:

[tex]HCl~+~NaOH~->~NaCl~+~H_2O[/tex]

The "titrant" in this case is the NaOH solution. If we know the concentration of NaOH (0.100M) and the volume of NaOH (38.2 mL=0.0382 L), we can calculate the moles using the molarity equation:

[tex]M=\frac{mol}{L}[/tex]

[tex]0.100~M=\frac{mol}{0.0382~L}[/tex]

[tex]mol=0.100~M*0.0382~L=0.0382~mol~of~NaOH[/tex]

Now, in the reaction, we have a 1:1 molar ratio between HCl and NaOH (1 mol of HCl is consumed for each mole of NaOH added). Therefore we will have the same amount of moles of HCl in the solution:

[tex]0.0382~mol~of~NaOH\frac{1~mol~HCl}{1~mol~NaOH}=0.0382~mol~HCl[/tex]

If we want to calculate the molarity of the HCl solution we have to divide by the litters of HCl used in the experiment (20 mL= 0.02 L):

[tex]\frac{0.0382~mol~HCl}{0.02~L}~=~0.191~M[/tex]

The concentration of the HCl solution is 0.191 M

I hope it helps!

Answer:

The metal block had a mass of 1.50kg

hope that helps you

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Answer:according to this picture

Explanation:

Answer:

AgBr

Explanation:

Silver bromide has a very low solubility product constant of about 7.7 ×10^-13 in pure water hence it is not quite soluble in pure water.

However, with NaCN, the AgBr forms the complex [Ag(CN)2]^2- which has a formation constant of about 5.6 ×10^8. This very high formation constant implies that the complex is easily formed leading to the dissolution of AgBr in NaCN.

The equation for the dissolution of AgBr in cyanide is shown below;

AgBr(s) + 2CN^-(aq) ----> [Ag(CN)2]^2-(aq) + Br^-(aq)

Answer:

C: The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.

Explanation:

I just did the assignment on EDGE2020 and it's 200% correct!  

Also, heart and rate if you found this answer helpful!! :) (P.S It makes me feel good to know I helped someone today!!)  :)  

Answer:

Explanation:

Given:

Mass of solute = 30 gram

Volume of water = 500 ml

Density = 1.15g/ml

Find:

(i)ppm

(ii) %w/v

(iii) %w/w

Computation:

Water in gram = 500 ml × 1.15 g/ml

Water in gram = 575 gram

In ppm

Concentration of MgSO4 = [30 / 575] × 10⁶

Concentration of MgSO4 = 0.0521 × 10⁶ ppm

in % w/v

Concentration of MgSO4 = [30 / 500] × 100

Concentration of MgSO4 = 6% w/v

in % w/w

Concentration of MgSO4 = [30 / 575] × 100

Concentration of MgSO4 = 5.21% w/w

Answer:

0.5 mol MgCl₂

Explanation:

Step 1: Write the balanced equation

Mg + 2 HCl → MgCl₂ + H₂

In words, 1 mole of Mg reacts with 2 moles of HCl to form 1 mole of MgCl₂ and 1 mole of H₂.

Step 2: Establish the appropriate molar ratio

The molar ratio of HCl to MgCl₂ is 2:1.

Step 3: Calculate the moles of MgCl₂ produced from 1 mole of HCl

1 mol HCl × (1 mol MgCl₂/2 mol HCl) = 0.5 mol MgCl₂

Answer:

it is 2.0, the above one is wrong

Explanation:

I did the test :

Answer:

Methyl radical

Explanation:

A radical is any specie that contains an odd number of electrons. We must note that the greater the number of alkyl groups which are attached to a carbon atom that bears the odd electrons, the more the degree of delocalization of the odd electrons and consequently the more stable we expect the free radical to be.

Hence the order of free radical stability is; Methyl < Primary < Secondary < Tertiary. Hence, we can easily see that the methyl radical is the least stable free radical.

Answer: Methyl radical

Explanation:

Answer:

- Addition of Ba(OH)2: favors the formation of a precipitate.

- Undergo a chemical reaction forming soluble species.

- Addition of CuSO4 : favors the formation of a precipitate.

Explanation:

Hello,

In this case, since the dissociation reaction of barium sulfate is:

[tex]BaSO_4(s)\rightleftharpoons Ba^{2+}(aq)+SO_4^{2-}(aq)[/tex]

We must analyze the effect of the common ion:

- By adding barium hydroxide, more barium ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).

- By adding sodium nitrate, the following reaction will undergo:

[tex]BaSO_4(s)+NaNO_3(aq)\rightarrow Ba(NO_3)_2(aq)+Na_2SO_4(aq)[/tex]

So the precipitate will turn into other soluble species.

- By adding copper (II) sulfate, more sulfate ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).

All of this is supported by the Le Chatelier's principle.

Best regards.

Answer:

The gas is Methane at 340K

Answer:

"Both signs are possible" is the correct choice.

Explanation:

As such that when both signals could have been the enthalpy change.

If the dissolution of borax in water is spontaneous, so the change in enthalpy should be negative.

Enthalpy of the reaction tells about the total amount of energy released or absorbed during any chemical reaction.

And for the spontaneous reaction, value of standard Gibb's free energy change of the reaction should be negative and formula will be represented as:
ΔG = ΔH - TΔS, where

ΔH = change in enthalpy

For the spontaneous reaction, value of enthalpy should be negative so that we get the negative value of ΔG.

Hence change in enthalpy should be negative.

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