Define degree of hardness of water? Mention different units.​

Answer:

See explanation

Explanation:

The valence electrons are electrons found on the valence (outermost) shell of an atom.

When an atoms form compounds, there is an exchange of valence electrons between the atoms of one element and the atoms of another element.

Let us consider a typical example, sodium has one valence electron and chlorine has seven valence electrons. This means that chlorine needs one electron to complete its octet while sodium needs to release one electron in order to attain the octet structure.

So, sodium gives out its one electron and becomes a stable sodium ion and chlorine accepts that electron and becomes a stable chloride ion. This is how the compound sodium chloride is formed.

Answer:

See explanation below

Explanation:

There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.

However we do not have a pH value here.

The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.

Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:

LiOH ---> Strong. If you try to dissociate :

LiOH ------> Li⁺ + OH⁻     The Li⁺ is a weak conjugate acid.

HF -----> Weak

HF --------> H⁺ + F⁻   The Fluorine is a relatively strong conjugate base.

HCl -----> Strong

This is actually one of the strongest acid.

NH₃ ------> Weak

Now writting the Ka and Kb expressions:

Ka = [H⁺] [F⁻] / [HF]

Kb = [NH₄⁺] [OH⁻] / [NH₃]

Finally, to calculate the [OH⁻] we need to use the following expression:

Kw = [H⁻] [OH⁻]

Solving for [OH⁻] we have:

[OH⁻] = Kw / [H⁺]

Remember that the value of Kw is 1x10⁻¹⁴. So replacing:

[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶

[OH⁻] = 1.43x10⁻⁹ M

And now, multiplying by 10¹⁰ we have:

[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰

Hope this helps

Strong acids and bases are those which completely ionized in body fluid, and weak acids and bases are those who does not completely ionized in body fluid.

Ka expression is used to differentiate between strong and weak acids.

[tex]\bold{\dfrac{[H+][F-]}{[HF]}}[/tex]

[tex]\bold{\dfrac{[NH_4^+] [OH^-]}{[NH_3]} }[/tex]

Given, [tex]\bold{ [H^+]=1\times10^-^6\; at \;25^oC}[/tex]

We know, [tex]\bold{ [H^+]\times[OH^-]=1\times10^-^6\; at \;25^oC}[/tex]

[tex]\bold{[OH^-]=\dfrac{1\times10^-^1^4}{6.2\times10^-^6} = 1.43\times10^-^9}[/tex]

Now, multiplying the value by [tex]10^1^0[/tex]

[tex]\bold{( 1.429\times10^-^9) \times 1\times10^1^0= 14.29}[/tex]

Thus, the value is 14.29.

Learn more about acid and base, here:

https://brainly.com/question/10468518

Answer:

light

Explanation:

light is plasma, which is a state of matter

Answer:

Incorrect

Explanation:

Mole ratios are derived from the coefficients in front of the number, N2O does not have a 2 in front of it, the real mole ratio would be 4/1

Answer:

Correct

Explanation:

I had the same problem and I put correct, and it was correct.

Answer: 49 joules

Explanation: gravitational potential energy = mgh

m= mass kg,  g= acceleration due to gravity 9.8 m/sec/sec, h= height m

=5*9.8.1 joules = 49 joules

Answer:

[tex]\%N=26.2\%\\\\\%H=7.5\%\\\\\%Cl=66.3\%[/tex]

Explanation:

Hello!

In this case, since the calculation of the percent composition of an element in a chemical compound is computing considering its atomic mass, subscript in the formula and molecular mass of the compound it is; for nitrogen, hydrogen and chlorine we have that ammonium chloride has a molar mass of 53.49 g/mol so the percent compositions are:

[tex]\%N=\frac{14.01*1}{53.49}*100\% =26.2\%\\\\\%H=\frac{1.01*4}{53.49}*100\% =7.5\%\\\\\%Cl=\frac{35.45*1}{53.49}*100\% =66.3\%[/tex]

Best regards!

The molecular formula : C₁₈H₁₈N₈

Given

62.41% C, 5.24% H, and 32.36% N

Required

The molecular formula

Solution

mol ratio

C : 62.41/12.0096 = 5.1967

H : 5.24/1.00784 = 5.1992

N : 32.36/14.0067 = 2.310

Divide by 2.310(smallest)

C : 5.1967/2.31=2.25

H : 5.1992/2.31 = 2.25

N : 2.31/2.31 = 1

Multiplied by 4

C : H : N = 9 : 9 : 4

The empirical formula : C₉H₉N₄

(C₉H₉N₄)n=346.40 g/mol

(12.0096 x 9 + 1.00784 x 9 + 14.0067 x 4)n=346.4

(108.0864+9.07056+56.0268)n=346.4

(173.184)n=346.4

n=2

The molecular formula : C₁₈H₁₈N₈

Answer:

Answer:

Reversible

Explanation:

Changes of state are physical changes in matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.

Answer:

Part. press. NO₂ in equilibrium is 0.590 atm

Explanation:

First of all, we determine the equilibrium:

N₂O₄ (g) ⇄ 2NO₂ (g)

These is a system of two unknown values.

In the begining we have x pressure of N₂O₄ and no value for NO₂.

During the reaction, y pressure has been released from N₂O₄. As ratio is 1:2, 2y will be the value for the pressure of NO₂. So in the equilibrium we have:

N₂O₄ → x - y

NO₂ → 2y

Data from the excersise states that the total pressure is 1 atm so we know that the sum of partial pressures in a mixture, will be the total one. In the equilibrium, total pressure will be:

(x-y) + 2y = 1 atm

x + y = 1 atm

Let's make the expression for Kp

Kp =  [Partial pressure NO₂]² / [ Partial pressure N₂O₄]

Kp = (2y)² / (x-y)

Kp = 4y² / (x-y)

We split the x value in the first equation:

x + y = 1 atm

x = 1 atm - y

x = 1 - y → we put this in the Kp expression

0.85 = 4y² / ( 1 - y - y)

0.85 = 4y² / 1 -2y

This is a quadractic equation

0.85 - 1.7y - 4y² = 0 where (a = -4, b = -1.7 c = 0.85)

(-b +- √(b² - 4ac)) / (2a)

(1.7 +-√((-1.7)² - 4 (-4) . 0.85) / 2 .(-4) → 0.295 = y

As [ Part. press. NO₂] in equilibrium is 2y → 0.295 . 2 = 0.590 atm

Based on the total pressure at equilibrium, the partial pressure NO₂ of at equilibrium is 0.590 atm.

From the equation of the reaction, the equilibrium is determined:

At equilibrium, N₂O₄ and NO₂ exist in the ratio 1 : 2.

N₂O₄ at x pressure releases y pressure to form NO₂ .

Thus at equilibrium:

N₂O₄ → x - y

NO₂ → 2y

Ptotal = 1 atm

Thus:

(x-y) + 2y = 1 atm

x + y = 1 atm

Also, Kp = 0.85

From the equation of the reaction:

Kp =  [Partial pressure NO₂]² / [ Partial pressure N₂O₄]

Kp = (2y)² / (x-y)

Kp = 4y² / (x-y)

Solving for x from the first equation:

x + y = 1 atm

x = 1 atm - y

Substitute x = 1 - y in the Kp expression

0.85 = 4y² / ( 1 - y - y)

0.85 = 4y² / 1 -2y

0.85 - 1.7y - 4y² = 0

Solving the quadractic equation:

where a = -4, b = -1.7 c = 0.85

y = (-b +- √(b² - 4ac)) / (2a)

y =(1.7 +-√((-1.7)² - 4 (-4) × 0.85) / 2 × (-4)

y = 0.295 or y = -0.720

We take positive value of y only.

Since partial pressure of NO₂ in equilibrium is 2y

Partial pressure of NO₂ = 0.295 × 2

Partial pressure of NO₂ = 0.590 atm

Therefore, the partial pressure of at equilibrium is 0.590 atm.

Learn more about about equilibrium partial pressure at: https://brainly.com/question/7183826

Answer:

Explanation:

From the given information:

The accuracy depends on the internal diameter of the cylinder. The cylinder with the least internal diameter is obviously more precise.

Let's assume 1% is the error of measurement.

Then, to measure 70 mL from 10 mL cylinder

The error = [tex]10 \times \dfrac{1}{100} \times 7[/tex]

= 0.7 mL

However; for a 100 mL cylinder, the error = 1 mL

Now,

The total volume for 10 mL = (70 + 0.7) = 70.7 mL

The total volume for 100 mL = (70 + 1 ) = 71 mL

Suppose the density (d) is same for both

Then;

the mass of 10 mL = ( d × 70.7) g

the mass pf 100 mL = (d × 71) g

Thus, the mass of 100 mL is greater than that of 10 mL.

Answer:Acceleration due to gravity on the moon is 1/6 times as that on the earth and we know that mass is property of the material it always remains same and weight is measure of gravitational force, hence

mass of object on moon is 60kg and weight =60g/6=10×10=100N

Explanation:

Answer:

Explanation:

The average kinetic energy for an ideal gas is directly proportional to the temperature. The average kinetic energy of the gas is a measure of the temperature of the gas molecule

Also, the average speed is usually proportional to the square root of temperature.

Similarly, there is a noticeable increase in K.E and speed in regard to temperature but sometimes it is not usually proportional.

However, provided that there is more temperature in Xe as compared to He, then after the mixture of both takes place at equilibrium; the temperature tends to fluctuate between (25 - 50)°C

Thus, since there is a decrease in temperature in Xe, both the average kinetic energy as well as the speed too will also decrease.

Answer:

an attraction between a partially positive region in one molecule and a partially negative region in another molecule....dipole-dipole interaction

an attraction between two temporarily polarized molecules...dispersion forces

an attraction between a negatively charged particle and a partially positive region in a molecule....ion dipole interaction

an attraction between a partially positive hydrogen atom in a molecule and a partially negative and highly electronegative atom on another molecule....Hydrogen bonding

Explanation:

Some molecules have permanent dipole. As a result of this, the positive part of one molecule may attract the negative part of the other molecule leading to dipole-dipole interaction.

Dispersion forces occur in all molecules and is as a result of temporary polarization of a molecule due to instantaneous dipole–induced dipole attractions.

If a charged particle is attracted by a dipole in a molecule, we call it ion-dipole interaction.

When hydrogen is bonded to a highly electronegative element, the positive end of the dipole is on hydrogen while the negative end of the dipole is on the electronegative element. Molecular associations often result from this permanent dipole and is called hydrogen bonding, e.g, HF.

Answer:

No

Explanation:

This does not mean that vinegar is insoluble totally. In fact, vinegar is soluble in water because water is a polar solvent.

For a substance to be soluble in another, it must obey the rule of solubility.

The rule states that "like dissolves like"

It implies that polar solvent will only dissolve polar solute.

Also, non-polar solvent will only dissolve non-polar solute.

Therefore, the answer is no, vinegar will dissolve in water.

Answer:

4

Explanation:

the one you ARE ON

Answer:

iconic bond is the answer

I hope it helps you ✌

Answer:

B

Explanation:

Answer:

24.9%

Explanation:

According to this question, mole fraction of NaCl in an aqueous solution is 0.0927. This means that the mole percent of NaCl in the solution is:

0.0927 × 100 = 9.27%

Let's assume that the solution contains water (solvent) + NaCl (solute), hence, the mole fraction of water will be;

100% - 9.27% = 90.73%

THEREFORE, it can be said that, NaCl contains 0.0927moles while H2O contains 9.073moles

N.B: mole = mass/molar mass

Given the Molar Mass

NaCl: 58.44 g/mol

H2O: 18.016 g/mol

For NaCl;

0.0927 = mass/58.44

mass = 0.0927 × 58.44

5.42g

For H2O;

9.073 = mass/18.016

mass = 9.073 × 18.016

= 16.35g

Total mass of solution = 16.35g + 5.42g = 21.77g

Mass percent of NaCl = mass of NaCl/total mass × 100

% mass of NaCl = 5.42g/21.77g × 100

= 0.249 × 100

= 24.9%

Answer:

24.9

Explanation:

Answer:

5.27 g of NaCl

Explanation:

The balanced equation for the reaction is given below:

Na₂CO₃ + CaCl₂ —> 2NaCl + CaCO₃

Next, we shall determine the mass of CaCl₂ that reacted and the mass of NaCl produced from the balanced equation. This can be obtained as follow:

Molar mass of CaCl₂ = 40 + (35.5×2)

= 40 + 71

= 111 g/mol

Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g

Molar mass of NaCl = 23 + 35.5

= 58.5 g/mol

Mass of NaCl from the balanced equation = 2 × 58.5 = 117 g

Summary:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 117 g of NaCl.

Finally, we shall determine the theoretical yield of NaCl. This can be obtained as follow:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 117 g of NaCl.

Therefore, 5 g of CaCl₂ will react to produce = (5 × 117)/111 = 5.27 g of NaCl.

Thus, the theoretical yield of NaCl is 5.27 g.

Answer:

See explanation

Explanation:

Chemical reactions are also referred to as chemical change. A chemical change often leads to the formation of new substances and is not easily reversible.

A chemical reaction may be accompanied by the emission of heat and light, formation of a precipitate, evolution of gas, or a color change.

These observable physical effects may tell us weather a chemical reaction has taken place or not so we have to observe the system closely for any of these effects stated above.

Answer:

1.93 x 10²⁶ formula units

Explanation:

Given parameters:

Number of moles of LiCl  = 3.2 x 10² moles  = 320moles

Unknown:

Number of formula units in this compound  = ?

Solution:

The mole is used a reference to determine the number of substances matters contain.

 A mole contains the Avogadro's number of particles.

 So;

       1 mole of a substance contains 6.02 x 10²³ formula units;

320 moles of LiCl will contain 320 x  6.02 x 10²³  = 1.93 x 10²⁶ formula units

Answer:

25.8 g/dL

Explanation:

A chemist prepares a solution of aluminum sulfate by weighing out 116.0 g of aluminum sulfate into a 450. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in g/dL of the chemist's aluminum sulfate solution. Be sure your answer has the correct number of significant digits.

Step 1: Given data

Step 2: Convert "V" to dL

We will use the following conversion factors.

450. mL × 1 L/1000 mL × 10 dL/1 L = 4.50 dL

Step 3: Calculate the concentration (C) of aluminum sulfate if g/dL

We will use the following expression.

C = m/V = 116.0 g/4.50 dL = 25.8 g/dL

Answer:

21.13 L

Explanation:

Step 1: Write the balanced equation

2 C₂H₆(g) + 7 O₂(g) ⇒ 4 CO₂(g) + 6 H₂O(g)

Step 2: Determine the appropriate volume ratio

Since all the gases are in the same container at the same temperature and pressure, the volume ratio is equal to the molar ratio, because the volume depends on the number of moles. The volume ratio of O₂(g) to H₂O(g) is 7:6.

Step 3: Determine the volume of H₂O produced from 24.65 L of O₂

24.65 L O₂ × 6 L H₂O/7 L O₂ = 21.13 L H₂O

The ocean is not a part of Earth's layers.

Answer:

Ocean

Explanation: