Determine the pH of 0.050 M HCN solution. HCN is a weak acid with a Ka equal to 4.9 x 10-10
DONE

Answer:

126g/mol

Explanation:

Molar mass is the mass of all the atoms in a molecule or compound in grams per mole (g/mol or gmol-1). To calculate the molar mass of a molecule, we first obtain the atomic weights of the individual elements in a periodic table. We then count the number of atoms and multiply it by the individual atomic masses.

•Atomic weight of Sodium Na = 23g/mol

•Atomic weight of Sulphur S= 32g/mol

•Atomic weight of Oxygen O = 16g/mol

•Find the sum of the atomic weights / molar masses of all the elements.

We have 2 atoms of Sodium Na and three atoms of Oxygen O. This implies that we will have to multiply the number of their atoms present by their atomic masses/molar masses.

Molar mass of Na2SO3= (number of atoms × atomic mass of Na) + (number of atoms × atomic mass of S) + ( number of atoms × atomic mass of O)

Molar mass of Na2SO3= (2×23g/mol) + (1×32g/mol) + (3×16g/mol)

Molar mass of Na2SO3= 46g/mol + 32g/mol + 48g/mol

Molar mass of Na2SO3 = 126g/mol

Therefore the molar mass of Na2SO3 is 126g/mol

Answer:

[tex]K_a=\frac{[H_3O^+][HCO_3^-]}{[H_2CO_3]}[/tex]

Explanation:

Several rules should be followed to write any equilibrium expression properly. In the context of this problem, we're dealing with an aqueous equilibrium:

Following the guidelines, we will omit liquid water and we will include all the other species in the constant. Each coefficient in the balanced equation is '1', so no powers required. Multiply the concentrations of the two products and divide by the concentration of carbonic acid:

[tex]K_a=\frac{[H_3O^+][HCO_3^-]}{[H_2CO_3]}[/tex]

Answer:

This statement is true.

Explanation:

Palaeontology can be described as the field of science under which the history of the earth is studied. Scientists use fossils to study the history of the earth as they provide evidence for history.

Fossils can be described as the remains of old, dead plants, animals, fungi, prokaryotes which are imprinted on rocks. These imprints provide evidence for the kind of organisms that once inhabited the land. For examples, fossil studies showed the existence of dinosaurs which are now extinct.

Answer:

how does gravity affect something

Explanation:

they study  physics.

hope this helped

Answer:

100 °C

Explanation:

Well it actually It depends on temperature and altitude . The boiling point of water is 100 °C or 212 °F at 1 atmosphere of pressure (sea level). However, the value is not a consistent. The boiling point of water depends on the atmospheric pressure, which changes according to elevation.

Florida experiences the first day of spring when Earth is in Position 3 with respect to the Sun. On or about March 21, known as the vernal equinox, neither hemisphere is favored, and the Sun crosses the celestial equator, marking the first day of spring.

Florida, which is located in the Northern Hemisphere, experiences the first day of spring when Earth is in Position 3 with respect to the Sun. On or about March 21, known as the vernal equinox, the Sun is on the celestial equator. This means that every place on Earth receives roughly 12 hours of sunshine and 12 hours of night. During this time, neither hemisphere is favored, and the Sun crosses the celestial equator, marking the first day of spring.

The empirical formula of caproic acid is C3H6O.

The empirical formula of caproic acid can be determined by calculating the molar ratios of carbon, hydrogen, and oxygen in the compound. The masses of each element in the sample can be used to calculate the number of moles. From the molar ratios, we can determine the simplest whole number ratio of elements, which gives us the empirical formula.

Given that the sample contains 0.0930g of Carbon, 0.0156g of Hydrogen, and 0.0413g of Oxygen, we can calculate the number of moles:

Next, we divide the number of moles for each element by the smallest number of moles to get the simplest whole number ratio. In this case, the smallest number of moles is 0.002583moles:

Therefore, the empirical formula of caproic acid is C3H6O.

Final answer:

After converting the given masses of C, H, and O to moles and finding their mole ratio, we determine that the empirical formula for caproic acid is C3H6O.

Explanation:

To determine the empirical formula of caproic acid from the given masses of Carbon (C), Hydrogen (H), and Oxygen (O), we must first convert the masses to moles:

Carbon: 0.0930 g C × (1 mol C / 12.01 g C) = 0.007744 mol C

Hydrogen: 0.0156 g H × (1 mol H / 1.008 g H) = 0.015476 mol H

Oxygen: 0.0413 g O × (1 mol O / 16.00 g O) = 0.002581 mol O

Next, we find the ratio of moles of each element by dividing each by the smallest number of moles.

C: 0.007744 mol / 0.002581 mol = 3

H: 0.015476 mol / 0.002581 mol = 6

O: 0.002581 mol / 0.002581 mol = 1

Thus, the mole ratio of Carbon, Hydrogen, and Oxygen in caproic acid is 3:6:1, which simplifies to 1:2:1/3. However, we cannot have a fraction in an empirical formula, so we multiply by 3 to get whole numbers.

The empirical formula is therefore represented as C3H6O with the assumption that the molecule has the smallest number integers for carbon, hydrogen, and oxygen that maintain the ratio.

Answer:

Explanation:

Actinoids are the series have 15 element in the periodic table.

Chemistry of actinoids are complicated because of the following reasons.

Due to all the above reasons it make difficult for a chemist to study about the chemical properties of actinoids.

Answer:

1

Explanation:

A decomposition reaction is a chemical reaction in which one product is decomposed to form two or more products. In chemistry, decomposition is primarily achieved by heating the substance at high temperature.

Chlorates normally are decomposed when they are reached at a significant high temperature and are normally used for oxidation purposes. In the given examples from the table:

Sodium chlorate is decomposed to Sodium chloride and oxygen. Potassium chlorate follow the same principle and so will Lithium.

So, the reaction becomes:

2LiClO₃ ----> 2LiCl + 3O₂

You can see that both Sodium chlorate (NaClO3) and Potassium chlorate (KClO3) gave exactly the same products. i.e. a chloride and oxygen.

Answer:

According to the proton theory of acids and bases by J. Brønsted and T. Lowry, the  acid is proton donor.

Explanation:

According to the Bronsted lowry concept an acid is substance that gives protons or hydrogen ion while,

Base is substance that accept hydrogen ion or proton.

Consider the following example:

NH₃ + HCl  →  NH₄⁺ + Cl⁻

In this example HCl is Bronsted lowry acid it gives H⁺ while ammonia is Bronsted lowry base because it accept H⁺.

This also gives the concept of conjugate acid and base. In given example Cl⁻ is conjugate base of HCl while NH₄⁺ is conjugate acid of ammonia.

The Brønsted-Lowry theory defines an acid as a proton donor and a base as a proton acceptor, which broadens the scope of acid-base reactions beyond aqueous solutions.

Brønsted-Lowry Theory of Acids and Bases

According to the Brønsted-Lowry theory of acids and bases, an acid is any substance that can donate a proton (H+), which is the same as a hydrogen ion. This concept broadens the definition of acids beyond the earlier Arrhenius definition, which was limited to substances that increase the concentration of H3O+ in water. In contrast, a Brønsted-Lowry base is any substance that can accept a proton from another molecule. One classic example is the reaction where ammonia (NH3) acts as a Brønsted-Lowry base by accepting a proton from a molecule of water, thereby forming ammonium (NH4+) and hydroxide (OH–) ions.

The theory allows for the classification of molecules in acid-base reactions based on the transfer of protons, which does not restrict the classification to aqueous solutions alone. Therefore, it provides a broader and more versatile framework for understanding acid-base chemistry compared to the Arrhenius definition.

Answer:

a. [tex]2.69 pm[/tex]

b. [tex]4.42\cdot 10^{-34} m[/tex]

Explanation:

The de Broglie wavelength can be found by the following equation:

[tex]\lambda_{dB} = \frac{h}{mv}[/tex]

Here:

[tex]\lambda_{dB}[/tex] is the de Broglie wavelength (in m);

[tex]h[/tex] is the Planck's constant, [tex]h = 6.626\cdot 10^{-34} J\cdot s[/tex];

[tex]m[/tex] is mass (in kg);

[tex]v[tex] is velocity (in m/s).

a. We need to know the mass of an electron here:

[tex]m_e=9.11\cdot10^{-31} kg[/tex]

And the speed of light:

[tex]c = 3.00\cdot 10^8 m/s[/tex]

The fraction of the speed of light is:

[tex]\omega = 0.90[/tex]

Substituting into the equation:

[tex]\lambda_{dB} = \frac{h}{\omega c m_e}=\frac{6.626\cdot10^{-34} J\cdot s}{0.90\cdot 9.11\cdot 10^{-31} kg\cdot 3.00\cdot 10^8 m/s} = 2.69\cdot 10^{-12} m = 2.69 pm[/tex]

b. Similarly, here we have:

[tex]m_b=150 g = 0.150 kg[/tex]

And the velocity of:

[tex]v = 10 m/s[/tex]

We obtain:

[tex]\lambda_{dB}={6.626\cdot 10^{-34} J\cdot s}{0.150 kg\cdot 10 m/s} = 4.42\cdot 10^{-34} m[/tex]

Notice that the wavelength of a large object is smaller by a fraction of:

[tex]\frac{2.69\cdot 10^{-12} m}{4.42\cdot 10^{-34} m} = 6\cdot 10^{21}[/tex]

This means the de Broglie wavelength of a macroscopic object is negligible compared to the wavelength of a microscopic object.

The number of neutrons that would equal a mass of one gram is approximately 6 x 10^23, which is also known as Avogadro's number.

To find the number of neutrons that would equal a mass of one gram, you would need to divide the desired mass (1 gram) by the mass of a single neutron, which is 1.67 x 10^-24 g. So, the calculation would be 1 g / 1.67 x 10^-24 g = approximately 6 x 10^23 neutrons. This number is also known as Avogadro's number, a familiar concept in chemistry and physics.

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Answer: 25.24moles

Explanation:Please see attachment for explanation

Answer:

20, 579, 1901

Explanation:

i don't know why you don't know this or whether this is a joke but there's a pattern sort of because you're just doing 1.2.3.4.5.6.7. and so forth.

Answer:

20

579

100899

Explanation:

Answer:

The answer is A on edge

Explanation:

Answer:

2H⁺(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2H₂O(ℓ)

Explanation:

You aren't dumb. You just need more time to learn the concepts.

There are three steps you must follow. You must write the:

1. Molecular equation

2HBr + Sr(OH)₂ ⟶ SrBr₂ + 2H₂O

To predict the states of the substances, we must remember some solubility rules:

Acids and bases react to give salts and water.

Thus, the molecular equation is

2HBr(aq) + Sr(OH)₂(s) ⟶ SrBr₂(aq) + 2H₂O(ℓ)

B. Ionic equation

You write all the soluble substances as ions.

2H⁺(aq)+ 2Br⁻(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2Br⁻(aq) + 2H₂O(ℓ)

C. Net ionic equation

To get the net ionic equation, you cancel the ions that appear on each side of the ionic equation.

2H⁺(aq) + 2Br⁻(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2Br⁻(aq) + 2H₂O(ℓ)

The net ionic equation is

2H⁺(aq) + Sr(OH)₂(s) ⟶ Sr²⁺(aq) + 2H₂O(ℓ)

The reaction between hydrobromic acid (HBr) and aqueous strontium hydroxide (Sr(OH)2) is a neutralization reaction. The overall chemical equation is HBr(aq) + Sr(OH)2(aq) → SrBr2(aq) + 2H2O(l), and the net ionic equation is 2H+(aq) + 2OH-(aq) → 2H2O(l).

The reaction between hydrobromic acid (HBr) and aqueous strontium hydroxide (Sr(OH)2) is a neutralization reaction that produces water and strontium bromide (SrBr2). The balanced overall chemical equation for this reaction is:

HBr(aq) + Sr(OH)2(aq) → SrBr2(aq) + 2H2O(l)

The complete ionic equation shows all of the ions present in solution:

2H+(aq) + 2Br−(aq) + Sr2+(aq) + 2OH−(aq) → Sr2+(aq) + 2Br−(aq) + 2H2O(l)

The net ionic equation only includes the species that are actually involved in the reaction (those that change their state or form new substances) and omits the spectator ions. For this reaction, the net ionic equation is:

2H+(aq) + 2OH−(aq) → 2H2O(l)

Here, 2H+ from the hydrobromic acid and 2OH− from the strontium hydroxide combine to form two molecules of water, which is the net change taking place in this reaction.

Answer:

Molarity = 0.9 M

Molality = 0.95 m

Explanation:

Data given:

mass of CaCl₂ = 23 g

mass of water = 217g

Density of water = 1g/mol

molality of solution = ?

molarity of solution = ?

Solution:

Molarity and Molality are terms used for concenteration of solution

Formula Used for Molarity

                    Molarity = moles of solute / liter of solution . . . . . (1)

So first we find number of moles of 23 g CaCl₂.

Formula used to find moles

                no. of moles = mass in g / molar mass

molar mass CaCl₂ = 40 + 2(35.5)

molar mass CaCl₂ = 40 + 71 = 111 g/ mole

So,

Put values in mole formula

                  no. of moles = 23 g / 111 g/mol

                   no. of moles = 0.21 mol

Now,

As for molarity we have to convert grams of water to liter

for this purpose we will use density formula

                      d= m/v

for volume rearrange the above equation

                     v = m/d . . . . . . . (2)

put vlue in above equation 2

                  v = 217 g / 1 (g/mL)

                    v = 217 mL

Now,

Total amount of solution = 23 + 217 = 240 mL

Now, Convert the mL to Liter

1000 = 1 L

240 mL = 240 /1000 = 0.24 L

So no we have the following required values to find molarity

no. of moles of CaCl₂ = 0.21 mol

liter of solution = 0.24 L

Put values in equation 1

                 Molarity = 0.21 mol / 0.24 L

                 Molarity = 0.9 M

_______________

To find Molality (m)

Formula used to find Molality

                 Molality = moles of solute / kg of solvent . . . . . . . (3)

So, no we have to convert grams of water to Kg

1000 g = 1 kg

217 g = 217 / 1000 = 0.22 Kg

Now,

Put values in equation

                 Molality = 0.21 mol / 0.22 kg

                 Molality = 0.95 m

So, the Molality =  0.95 m

Answer:

Explanation:

Valance electrons are loosely held electrons of an atom. They are involve in chemical reaction. Consider the example of metals such as group two metals. All these have two valance electrons. They needed six electrons to complete the octet or loses two valance electrons to get complete octet. Thus its easier to remove two electrons than getting six electrons. These metals remove two electrons and form cations.

Now consider the example of nonmetals such group sixteen. They needed two electrons to get complete octet or remove six electrons to get complete octet. Thus its easier for them to get two electrons and they form anion. When group two metals cation and group sixteen anions combine they form compound and chemical reaction occur.

Group two metals also combine with halogens. Two halogens atoms combine with one alkaline earth metal atom to cancel the charge and make compound neutral.

They react with oxygen and form oxide.

2Ba   +   O₂   →    2BaO

2Mg  +   O₂   →    2MgO

2Ca +   O₂   →    2CaO

Oxygen carry -2 charge while Ca, Mg and Ba +2 and make the compound neutral because charges are equal in magnitude.

With sulfur,

Mg + S   →  MgS

Ca + S   →  CaS

Ba + S   →  BaS

Sulfer carry -2 charge while Ca, Mg and Ba +2 and make the compound neutral because charges are equal in magnitude.

Answer:They are all controlled by the human beings.

Explanation:

The selective breeding, cloning and genetic engineering are some of the techniques which is induced by the human efforts.

In case of selective breeding the male and female species having the selective characters are mated with each other so that the offspring produced  has the desired characters. It neither requires any enzyme nor uses udder cells.

In case of genetic engineering, the gene of interest is inserted in the bacterial species by the help of vector so that when the bacterial species amplify the gene of interest. This is how the desired products are produced by bacterial species. Example: Insulin production.

Cloning can be defined as another technique made by human beings in which the genetically identical species is made naturally or artificially for the benefit of the mankind.

Answer:

b, they are controlled by humans

Explanation:

Final answer:

To determine the number of molecules of sugar in a can of soda, you need to calculate the number of moles of sugar in the can and then use Avogadro's number to convert from moles to molecules. The molar mass of sugar is calculated by summing up the atomic masses of carbon, hydrogen, and oxygen. Avogadro's number (6.022 x 10^23) tells us that one mole of any substance contains 6.022 x 10^23 molecules.

Explanation:

In order to determine the number of molecules of sugar in a can of soda, we need to know the number of moles of sugar in the can and then use Avogadro's number to convert from moles to molecules. To calculate the number of moles of sugar, we need to know the molar mass of sugar. The molar mass of sugar, C12H22O11, is calculated by summing up the atomic masses of carbon, hydrogen, and oxygen.

Once we have the molar mass of sugar, we can calculate the number of moles of sugar in the can by using the formula: Moles = Mass / Molar Mass. Once we have the number of moles, we can use Avogadro's number (6.022 x 10^23) to convert from moles to molecules. Avogadro's number tells us that one mole of any substance contains 6.022 x 10^23 molecules.

Please note that the specific molar mass of sugar and the exact amount of sugar in a can of soda would need to be provided in order to calculate the exact number of molecules of sugar in the can.

Answer: answer is D

Explanation:

Answer:

When observing the image inside a spoon, the image seems to be bent or cut, because the rays of light deviate with a  certain angle of incidence, since they travel slower when passing from the air, where there are less particles, to the liquid, where there are more particles .

When turning the spoon a specular reflection is observed, it is when the surfaces are polished, the light rays are reflected with and angle of reflection in only one direction and in an orderly manner. This is why images are formed that look like copies of objects.

Explanation:

Reflection and refraction of waves are two phenomena that occur when a wave that propagates in a certain medium meets a separation surface with another medium.

Reflection is the change in direction that a wave experiences when it comes into contact with the surface that separates two media while returning to the point where it originated. Refraction is the change of direction and speed that a wave undergoes obliquely on a surface that separates two media with different refractive indices.

Looking at your reflection in a shiny soup spoon is a result of light reflection. The angle of incidence and angle of reflection are equal, resulting in an upright and undistorted image. The back of the spoon is concave, causing an upside down and distorted reflection.

When you look at your reflection in the side of a shiny soup spoon, you will see an upright and undistorted image. This is because of the reflection of light. The angle at which light hits the spoon, known as the angle of incidence, is equal to the angle at which it reflects off the spoon, known as the angle of reflection. The back of the spoon is concave, so when you look at your reflection in it, the image will be upside down and distorted.

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Answer: D the rate that varies more with temperature

Explanation: reaction with greater activation energy is not feasible ordinarily as the reacting molecules have little or no energy to overcome the activation energy. But as the temperature of the reaction is increased, the reacting molecules gains more energy to overcome the energy barriers(activation energy) hence proceeding to form products. In this case, the rate of the reaction depends on the temperature. So an increase in temperature will increase the kinetic energy of the molecules thereby increasing the rate of the reaction and a decrease in temperature will leads to a decrease in the rate of the reaction.

Final answer:

In comparing two chemical reactions, the reaction with the greater activation energy typically has the slower rate. This is due to fewer molecules being able to overcome the higher energy barrier to react. The correct answer to the question is (A) the slower rate.

Explanation:

In comparing two reactions, if one has a greater activation energy, it generally has the slower rate. Activation energy is the energy required to initiate a reaction, and it plays a critical role in determining the rate of a chemical reaction. A higher activation energy means that fewer molecules possess the necessary energy to overcome the barrier and react at a given temperature. Thus, the reaction with a higher Ea will have a slower rate.

Therefore, the correct answer to the question is: (A) the slower rate. As temperature increases, reactions with high activation energies can speed up considerably, because the proportion of molecules with sufficient energy to overcome the Ea increases significantly. Conversely, reactions with lower activation energies are less sensitive to temperature changes since a high proportion of molecules already have enough energy, even at lower temperatures.

Answer:

-21 kJ·mol⁻¹  

Explanation:

Data:

                    H₃O⁺ +  OH⁻ ⟶ 2H₂O

       V/mL:    50         50  

c/mol·dm⁻³:   1.0         1.0

ΔT = 4.5 °C  

       C = 4.184 J·°C⁻¹g⁻¹

C_cal = 50 J·°C⁻¹

Calculations:

(a) Moles of acid

[tex]\text{Moles of acid} = \text{0.050 dm}^{3} \times \dfrac{\text{1.0 mol}}{\text{1 dm}^{3}} = \text{0.050 mol}\\\\\text{Moles of base} = \text{0.050 dm}^{3} \times \dfrac{\text{1.0 mol}}{\text{1 dm}^{3}} = \text{0.050 mol}[/tex]

So, we have 0.050 mol of reaction

(b) Volume of solution

V = 50 dm³ + 50 dm³ = 100 dm³

(c) Mass of solution

[tex]\text{Mass of solution} = \text{100 dm}^{3} \times \dfrac{\text{1.00 g}}{\text{1 dm}^{3}} = \text{100 g}[/tex]

(d) Calorimetry

There are three energy flows in this reaction.

q₁ = heat from reaction

q₂ = heat to warm the water

q₃ = heat to warm the calorimeter

q₁ + q₂ + q₃ = 0

     nΔH   +         mCΔT       + C_calΔT = 0

0.050ΔH + 100×4.184×4.5 +   50×4.5  = 0

0.050ΔH +          1883        +      225    = 0

                                  0.050ΔH + 2108 = 0

                                              0.050ΔH = -2108

                                                        ΔH = -2108/0.0500

                                                              = -42 000 J/mol

                                                              = -42 kJ/mol

This is the heat of reaction for the formation of 2 mol of water

The heat of reaction for the formation of mol of water is -21 kJ·mol⁻¹.

Answer:

They are jogging side by side at 5 m/s

Let's distinguish between the concepts of speed and velocity:

The first condition we have here is the fact that two people have the same speed, this means they are moving at the same rate of change of distance. The second condition must be met as well, if we wish them to have the same velocity, this means they should be moving in the same direction, let's say, along the positive or negative x-axis, but not in opposite directions.

Answer:

they need a rough surface to help adhesion

Explanation:

Explanation:

The van der Waals' forces are the forces that exist between the millions of separate water molecules, and not between the hydrogen and oxygen atoms in the case of water. Dipole-Dipole forces are one of van der Waals' three forces. ... For example, HCl comprised of the atom Hydrogen and Chlorine is polar.

Answer:

The frequency will reduced to half if you increase the wavelength to double.

The speed of the wave is constant and equal to [tex]3\times 10^8\ m/s[/tex].

Explanation:

The wavelength of a wave varies inversely to frequency of the wave.

The relation between the frequency and wavelength of a wave is given as:

[tex]v=f\lambda[/tex]

Here,

[tex]v\to \textrm{speed of the wave which is always a constant in vacuum}\\f\to \textrm{frequency of the wave}\\\lambda\to \textrm{wavelength of the wave}[/tex]

Therefore, as the wavelength increases then the frequency will decrease.

Similarly, as the wavelength of the wave decreases, then the frequency will increase.

Now, if we increase the wavelength by a factor 'k', the frequency will reduce by the same factor 'k'.

Here, the wavelength is doubled which means it increases by a factor of '2'. Therefore, the frequency will decrease by a factor of '2'.

So, the frequency will reduced to half if you increase the wavelength to double.

The speed of the wave is constant as the increase in wavelength is compensated by a decrease in frequency and thus the product of the two remains same. Therefore, speed of wave is equal to [tex]3\times 10^8\ m/s[/tex].

The diameter of  the pool is 4

Explanation:

To calculate the diameter we must write the values given in the question, here

The circumference of the pool is given as C=12.56 feet.

To calculate the diameter of the pool,

If radius is given, Multiply the radius by 2

If Circumference is given divide the circumference by Pi (π)

the constant value for  Pi (π)=3.14

Diameter(D)= C/π

12.56/3.14

=4

The diameter for the plastic wading pool is 4

Answer:

The correct answer is A) single

Explanation:

In the case of the Bromo atom, it requires 1 electron to complete its octet, therefore it shares 1 electron with the other Bromo atom.