What are the main modifications of John Dalton's atomic theory

Answer:

It is a colourless, odourless, tasteless gas that is the most plentiful element in Earth's atmosphere and is a constituent of all living matter.

Explanation:

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Answer:

Nitrogen is a gas

Explanation:

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Answer:

b) empty space

Explanation:

A mechanical cannot travel through empty space. So option (b) is correct.

A mechanical wave is a wave which needs a material medium for its propagation. For example sound, water waves etc . The medium required by the wave can be a solid, liquid or a gas. Empty space doesn't have any medium, so a mechanical wave cannot travel through empty space.

Explanation:

Earth is known as the "Blue Planet" because 71 percent of the Earth's surface is covered with water. Water also exists below land surface and as water vapor in the air. Water is a finite source. The bottled water that is consumed today might possibly be the same water that once trickled down the back of a wooly mammoth. The Earth is a closed system, meaning that very little matter, including water, ever leaves or enters the atmosphere; the water that was here billions of years ago is still here now. But, the Earth cleans and replenishes the water supply through the hydrologic cycle.

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Answer: 2,25 mol

Explanation: 2Al + 3CuSO4 → Al2(SO4)3 + 3Cu

                    1,5 mol                                                       (1,5*3)/2 mol = 2,25 mol

Answer:

See explanation

Explanation:

For the first question, we can see that the pressure is constant so we apply Charles law;

V1/T1 =V2/T2

V1T2 = V2T1

V1= 4.5 L

T1= 27 + 273 = 300 K

V2= ?

T2= 127 + 273 = 400 K

V2= V1T2/T1

V2= 4.5 × 400/300

V2= 6L

For question 2, Charles law is also used;

V1/T1 =V2/T2

V1T2 = V2T1

T1= 338 K

V1= 0.480 L

T2= ?

V2= 9.2 L

T2= V2T1/V1

T2= 9.2 × 338/0.480

T2= 6478.3 K

Answer:

A range of organic molecules can undergo combustion. Pyridine (C5H5 combustion in the unbalanced reaction shown below wtar o 4 CsH5N + O2 +H2O + CO2 + NO a) Write the balanced equation. (2 points) # 41 CH N +170 70 the flow, t- b) Find the percent yield for the reaction if 10.0 g of pyridine dioxide. (2 points)

Explanation:

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Answer:

C

Explanation:

KE at B is max and PE is 0

KE at C is 0 and PE is max

so when student swings from C to B

its KE increases

and PE decreases

Answer:

2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)

Explanation:

In a redox reaction, we must ensure that the number of electrons gained equals the number of electrons lost in the reduction and oxidation half reaction equations respectively.

Having that in mind;

Oxidation half reaction;

2Rb(s) ---->2Rb^+(aq) + 2e

Reduction half equation;

Sr^2+(aq) + 2e---> Sr(s)

Hence, the overall redox reaction equation is;

2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)

Answer:

A form of energy that can be used by cells.

Explanation:

Answer:

C) Polar

Explanation:

The correct answer is polar

The attraction of sodium and chloride ions by the water is mediated by the polar nature of water. Thus, option C is correct.

The polarity is given as the formation of the partial positive and negative charge over the species in the ionization process.

Water molecule is having one hydrogen bounded with 2 oxygen atoms, and oxygen being more electronegative develops a partial negative charge, while hydrogen develops a partial positive charge.

The positive charge hydrogen and the negative charge oxygen attracts the opposite charge sodium and chloride ions. Thus, the attraction is mediated due to the polar nature of water. Hence, option C is correct.

Learn more about polarity, here:

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Answer:

Option A and B

Explanation:

(a) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)

Delta G = Delta H – T * DS

Substituting the given values, we get –  

Delta G = -84 -298 *(125/1000) = -121.25  KJ/mol

Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics

(b) DeltaH = -84 kj mol-2 (-20 kcal mol-1), DeltaS = -125j mol-2K-1)(-30 cal mol-1 K-1)

Delta G =-84 -298 *(-125/1000) = -46.75 KJ/mol

Delta G is negative hence the process is spontaneous and will not violate the second law of thermodynamics

(c) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(+30 cal mol-1 K-1)

Delta G = 84 -298 *(125/1000) = +46.75 KJ/mol

Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics

(d) DeltaH = +84 kj mol-2 (+20 kcal mol-1), DeltaS = +125j mol-2K-1)(-30 cal mol-1 K-1)

Delta G = 84 -298 *(-125/1000) = + 121.25  KJ/mol

Delta G is positive hence the process is non-spontaneous and will violate the second law of thermodynamics

Explanation:

the answer is in the above image

Answer:

both groups and periods

Answer:

groups

Explanation:

Elements in the same group have similar chemical properties because they have the same number of outer electrons and the same valency

Answer:

Limiting reagent is the potassium carbonate.

Percent yield of calcium carbonate is: 39.3 %

Explanation:

The reaction is:

CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl

Formula for percent yield is:

(Produced yield / Thoeretical yield) . 100

Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.

1 mol of chloride need 1 mol of carbonate.

14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂

12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.

Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.

Ratio is also 1:1, with calcium carbonate.

1 mol of potassium carbonate produces 1 mol of calcium carbonate

then, 0.0889 moles will produce the same amount of CaCO₃

We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g

That's the theoretical yield; to find the percent yield:

(3.494 g / 8.89g) . 100 = 39.3%

Answer: The correct option is A) 8.97

Explanation:

To calculate the [tex]K_b[/tex] of a reaction, we use the equation:

[tex]K_a\times K_b=10^{-14}[/tex]

where,

[tex]K_a[/tex] = acid dissociation constant of acetic acid = [tex]1.86\times 10^{-5}[/tex]

[tex]K_b[/tex] = base dissociation constant

Putting values in above equation, we get:

[tex](1.86\times 10^{-5})\times K_b=10^{-14}\\\\K_b=\frac{10^{-14}}{1.86\times 10^{-5}}=5.37\times 10^{-10}[/tex]

To calculate the hydroxide ion concentration of conjugate base, we use the equation:

[tex][OH^-]=\sqrt{K_b\times \text{[Conjugate base]}}[/tex]

where,

[Conjugate base] = 0.10 M

Putting values in above equation, we get:

[tex][OH^-]=\sqrt{(5.37\times 10^{-10})\times 0.1}[/tex]

[tex][OH^-]=7.33\times 10^{-6}[/tex]

To calculate the pOH of the solution, we use the equation:

[tex]pOH=-\log [OH^-][/tex]

[tex]pOH=-\log (7.33\times 10^{-6})[/tex]

[tex]pOH=5.03[/tex]

To calculate the pH of the solution, we use the equation:

pH + pOH = 14

pH + 5.03 = 14

pH = (14 - 5.03) = 8.97

Hence, the correct option is A) 8.97

Answer:

As it is given that the initial concentration of sulfuric acid is 0.010 M.

Hence, the ICE table for first dissociation of sulfuric acid is as follows.

Initial:         0.010                       0        0

Change:     -0.010                +0.010    +0.010

Equilibrium:    0                    0.010        0.010

When second dissociation of sulfuric acid occurs which is partial then the ICE table will be as follows.

Initial:                 0.010                    0        0.010

Change:              -x                       +x          +x

Equilibrium:       0.010 - x              x            0.010 + x

Since, it is given that . Hence, formula  for  is as follows.

                               x = 0.0045

Hence, by using the equilibrium concentrations from the table and value of x we get the following.

    = x,        

                   = 0.0045 M

    = 0.010 - x

                     = 0.010 - 0.0045

                     = 0.0055 M

     = 0.010 + x

                   = 0.010 + 0.0045

                   = 0.0145 M

Explanation:

Answer:

a. The longest chain is chosen incorrectly.

Explanation:

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In this case, according to the given information, it turns out possible for us to firstly draw the structural formula of the 1,3-Dimethylbutane:

[tex]CH_3-CH_2-CH(CH3)-CH_2-CH_3[/tex]

Thus, we can see that the correct name should be 3-methylpentane since the longest chain was chosen incorrectly, as it must have five carbon atoms.

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Answer:

true

Explanation:

Answer:

true

Explanation:

Answer:

482

Explanation:

Answer:

The netto reaction equation is:

2 OH- + 2H+ = 2 H2O  

So the answer is 2 moles.

Answer:

2 K(s) + Cl₂(g) ⟶ 2 KCl(s)

2 Cu(s) + O₂(g) ⟶ 2 CuO(s)

Explanation:

Both reactions are synthesis reactions (two substances combine to form another).

Reaction: K(s) + Cl₂(g) ⟶

The product is the binary salt KCl. The balanced chemical equation is:

2 K(s) + Cl₂(g) ⟶ 2 KCl(s)

Reaction: Cu(s) + O₂(g) ⟶

The most likely product is the metal oxide CuO. The balanced chemical equation is:

2 Cu(s) + O₂(g) ⟶ 2 CuO(s)

Answer:

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Answer:

This bubbled-up magma is cooled by frigid seawater to form igneous rock. This rock (basalt) becomes a new part of Earth's crust. Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor.

Explanation:

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Answer:

mixture of compounds molecular weight

Explanation:

Gas Chromatography-mass spectrometry is used to find the mixture of compounds of each compound in a molecular weight. The Gas Chromatography also known as Mass Spectrometry (GC/MS) is an instrument that is used to separate chemical mixtures and identifies the components at a molecular level. It is one of the most accurate tools used for analyzing samples of the environment.

Answer:

No, I can not identify the contents of each bottle using solubility and polarity (with H2O) information

Explanation:

While it is true that polar substances dissolve in water and nonpolar substances do not dissolve in water, the task here is to specifically identify the contents of each of the bottles.

Solubility in water can not tell us exactly what liquid is which substance. For instance, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene and cyclooctane are all insoluble in water. The fact that they do not dissolve in water does not tell us which liquid is which compound.

Even though acetic acid is miscible with water, it is not a conclusive prove that the liquid is acetic acid since other polar organic compounds are also miscible in water.

It is only by determining the boiling point of each substance that I can conclusively identify the contents of each bottle since boiling point is an intrinsic property of substances.

Answer:

C) Both

Explanation:

Whenever we mix any pure form of a compound with some other form of a compound which is not in the other standard pure state, this results in the melting point of mixture to get dispersed and it becomes broad form.

Thus, when a known compound of 3-Nitroaniline mixes with both 3-Nitroaniline and 4-Nitrophenol, the melting point of the compound becomes depressed and board.

Thus the correct option is (C).

Answer:

100 mL

Explanation:

The reaction that takes place is:

First we convert 500 mg of CaCO₃ into mmoles, using its molar mass:

Then we convert 5 mmoles of CaCO₃ into HCl mmoles, using the stoichiometric coefficients of the balanced reaction:

Finally we calculate the volume of a 0.10 M HCl solution (such as stomach acid) that would contain 10 mmoles:

Answer:

a.

Explanation:

Assuming that Liquid X is considered to possess a greater viscosity as well as higher surface tension than liquid Y. Then, liquid X will tend to harbour more pressure inside the liquid.

In addition to that, the greater the surface tension, the greater the force required to expand the liquid's surface area.

This in turn makes the force required to make the loop 5% wider to be greater in FX rather than FY.

Thus, option a is the correct answer.