I need help with 17,18,19,& 21

Answer:

pH = 6.76

Explanation:

Ka = 3.4x10⁻⁷; 3.0x10⁻⁵g

The molarity of the vitamin B1 -Molar mass: 327.268g/mol- solution is:

3.0x10⁻⁵g * (1mol / 327.268g) = 9.167x10⁻⁸M

The Ka expression is:

Ka = 3.4x10⁻⁷ = [H⁺] [B1-] / [B1]

Where B1- is the conjugate base of vitamin B1,

In equilibrium, the concentrations are:

[H⁺] = X

[B1-] = X

[B1] = 9.167x10⁻⁸M - X

Where X is reaction coordinate

Replacing:

3.4x10⁻⁷ = [X] [X] / [9.167x10⁻⁸M - X]

3.117x10⁻¹⁴ -3.4x10⁻⁷X = X²

3.117x10⁻¹⁴ -3.4x10⁻⁷X - X² = 0

Solving for X:

X = -4.15x10⁻⁷M. False solution. There is no negative concentrations.

That means from the equilibrium of vitamin B1, the [H⁺] = 7.51x10⁻⁸M

From the autoinoization of water:

[H⁺] = 1.0x10⁻⁷M

[H⁺] in the solution is:

1.0x10⁻⁷M + 7.51x10⁻⁸M = 1.751x10⁻⁸M

As pH = -log[H⁺]

Answer:

% Free space in water = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%

% Free space in ice  = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%

Explanation:

As given ,

Density for ice at 0⁰C = 0.917 g/ml

Density for water at 0⁰C = 0.999 g/ml

Radii of H atoms = 37 pm

Radii of O atoms = 66 pm

Now,

Consider 1 ml of water = 1 cm²

As , we know that mass of water in 1 cm² = 0.999 g

Moles of water = [tex]\frac{0.999}{18} = 0.056[/tex]

Volume of H₂O = 1.624×[tex]10^{-31}[/tex] m²

Now,

Volume occupied by water = 0.056×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²

                                              = 5.48×[tex]10^{-9}[/tex] m²

⇒Volume occupied by water = 5.48×[tex]10^{-9}[/tex] m²

Now,

Free space = 1×[tex]10^{-6}[/tex]  - 5.48×[tex]10^{-9}[/tex] = 9.95×[tex]10^{-7}[/tex] m²

% Free space = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%

Now,

Consider 1 ml of ice  = 1 cm²

S.I unit of ice = 1×[tex]10^{-6}[/tex] m²

As , we know that mass of water in 1×[tex]10^{-6}[/tex] m² = 0.917 g

Moles of ice = [tex]\frac{0.917}{18} = 0.012[/tex]

Volume of H₂O = 6.022×[tex]10^{23}[/tex] ×0.012

Volume of ice unit = [tex]\frac{4}{3} \pi (37*10^{-12})^{3} *2 + \frac{4}{3} \pi (66*10^{-12})^{3} = 1.624*10^{-31}m^{3}[/tex]

Now,

Volume occupied by water = 0.012×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²

                                              = 1.17×[tex]10^{-9}[/tex] m²

⇒Volume occupied by water = 1.17×[tex]10^{-9}[/tex] m²

Now,

Free space = 1×[tex]10^{-6}[/tex]  - 1.17×[tex]10^{-9}[/tex] = 9.98×[tex]10^{-7}[/tex] m²

% Free space = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%

Answer:

Carbon and oxygen are chemically bonded in it.

Explanation:

The other answer choices do not apply for compounds, but rather for mixtures instead.

Answer:

K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷

Explanation:

The equation for the reaction is given below:

7CH₄(g) + 8N₂(g) +2O₂(g) + 17H₂O(g) + 7K₂CO₃(s) —> 16NH₃(g) + 14KHCO₃(s)

Equilibrium constant (K) =..?

Equilibrium constant, K for a reaction is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.

Thus, the equilibrium expression for the Harber-Bosch process for the synthesis of ammonia can be written as shown below:

K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷

Answer:

Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available in limited supplies. This is usually due to the long time it takes for them to be replenished. Renewable resources are replenished naturally and over relatively short periods of time

Answer:

See explanation

Explanation:

Let us look at the situation closely, the undissociated Hmo is red in colour while the mo^- is yellow in colour.

This means that an acidic solution will appear red while a basic solution will appear yellow in colour.

NaC2H3O2 is a basic salt. When it is introduced, the acetate ion pulls a proton from water forming  CH3COOH. CH3COOH is a weak acid and largely does not dissociate, it means that the undissociated acid remains in the solution leaving only the OH^- ions floating around thereby making the solution basic.

The colour of the system now changes to yellow.

Consider the equilibrium;

CH3COO^-(aq) + H2O(l) ------> CH3COOH(aq) + OH^-

Addition of NaC2H3O2  causes the equilibrium of this system to shift to the right.

The methyl orange water equilibrium also shifts towards the position where more mo^-(yellow) is produced.

Answer:

i gussss D is the answer may be

Answer:

A. The mass of a system does not change during a chemical reaction

Explanation:

Correct Answer

Answer:yes anything can be addictive

Explanation:

Answer:

While caffeine produces a small rise in dopamine, it does not cause the large surge that unbalances the reward circuits in the brain and is necessary for an addiction. So even though the word “addiction” is often used casually, caffeine is not addictive (scientifically speaking).

Answer: 33.3 moles

Explanation: 67.2 g H2 = 67.2/2.016 = 33.3 moles

Solar Radiation(Basically Radiation)

Answer: 0.25 mol × (6.02214 × 1023 /mol) = 1.5 × 10

Explanation: Hope that helps

Answer:

Test it with a blue light that is 45 cm away.

Explanation:

Answer:

2KF+MgSO4

Explanation:

The correct product of the reaction above is 2KF + MgSO4.

A chemical reaction is a reaction in which the reactants or reacting substances react or combine together to produce the products.

Therefore, The correct product of the reaction above is 2KF + MgSO4.

Learn more about chemical reactions below.

https://brainly.com/question/11231920

#SPJ2

Answer:

Bohr placed the electrons in distinct energy levels.  Rutherford described the atom as consisting of a tiny positive mass surrounded by a cloud of negative electrons. Bohr thought that electrons orbited the nucleus in quantized orbits. Also, rutherfords was just a hypothesis while Bhor took the time to make his an experiment

Answer:

1.6734 g\ml..hope it helps

Answer:

The property P measured, was a chemical property of X; its acidity

The property D measured, was a physical property of X; its density

The property V measured, was a physical property of X; it's viscosity probably.

Explanation:

1. The property V that was measured is the acidity of X. The acidity of X is a measure of the concentration of hydrogen ions present in it. When drops of another solution, containing dissolved sodium hydroxide, are slowly added, and a pH indicator is used to determine when the sodium hydroxide has completely reacted with X, the procedure determines the concentration of X that would neutralize the base, sodium hydroxide.

2. The property of X determined in the step is the density of X, a physical property. First the volume of X was determined by the displacement method. Then the density of X is calculated from its mass and volume.

3. Since during the determination of the property V, there was no alteration done to the chemical constitution of X, the property thus determined is a physical property. Melting of the sample is a physical change and likewise its flow rate through a very thin tube.

Answer:

-1

Explanation:

According to this question, the oxidation state/number of H and O in C2H4O is +1 and -2 respectively.

The oxidation state of carbon in the compound can be calculated thus:

Where;

x represents the oxidation number of C

C2H4O = 0 (net charge)

x(2) + 1(4) - 2 = 0

2x + 4 - 2 = 0

2x + 2 = 0

2x = -2

Divide both sides by 2

x = -1

The oxidation number of C in C2H4O is -1.

Explanation:

Selenium and tellurium are rare elements, respectively, in order of crustal abundance. However, polonium, on account of its radioactive decay, is less abundant. The main source of selenium and tellurium is the anode slime deposited during the electrolytic refining of copper.

Answer:

B. Similar fossils were found in different continents.

Answer:

B. Similar fossils were found in different continents.

Explanation:

Answer:

propane-1-ol.

is the ans.

ok

is the name

ok

How do I know I'm a fish eh sorry

Answer:

The correct option is d. ion exchange chromatography and gel filtration chromatography

Explanation:

The mixture contains proteins with different isoelectric points and molecular weights. Ion exchange chromatography separates the proteins with different electric charges, which depend on the isoelectric point. At certain pH of the aqueous medium, the proteins will have a certain electric charge and they will be retained differently in the stationary phase. Proteins A and D have similar isoelectric points (around 4.0) and maybe they cannot be efficiently separated by this method; the same occurs with protein B and C (with an isoelectric point around 9.0). To separate proteins A from D and protein B from C, it could be used gel filtration chromatography. This separation method is based on differences in molecular weights. So, at the end of the process, we will obtain the proteins A, B, C, D separated one from each other.

Answer:

The answer is "A"

Explanation:

Please find the complete question in the attachment file.

[tex]\to R(s)= \frac{As}{K+s}[/tex]

when the s in the approach, that is infinity R(s) tends

[tex]\to \frac{A}{\frac{K}{s}+1} \\\\ \to\frac{A}{0+1} \\\\ \to\frac{A}{1} \\\\ \to A[/tex]

Answer:

Air temperature increases.

Explanation:

The air temperature at Riverdale School increases if the groundwater system were used because this system uses very huge amount of water than the other system. By using more molecules having the same temperature, the thing with more molecules has more total kinetic energy or thermal energy than the thing with fewer molecules so that's why air temperature of the school is increases.

Answer:

the crust is the outermost layer

Explanation:

the mantle is under the crust, the core is the innermost layer

land and water.is for crust-mantle. contain semi-molten iron and nickel please make the question clear

Answer:

answer in picture

Explanation:

Answer

Using the law of reflection—the angle of reflection equals the angle of incidence—we can see that the image and object are the same distance from the mirror. This is a virtual image, since it cannot be projected—the rays only appear to originate from a common point behind the mirror.

Explanation:

Hope this helps someone

Answer:

Lead

Explanation:

The subatomic particles within an atom can be used to know the atom or element given.

Of particular interest is the number of protons within the atom.

The periodic table is based on the atomic number of atoms. This atomic number is the number of protons within an atomic space.

So; If we know the number of protons within an atom, we can know the element.

The number of protons given is 82, the element is  therefore lead.

Answer:

The atomic number of polonium is 84. The atomic number lead is 82.

Explanation:

Explanation:

H2SO3 is more acid than H2TeO3. Since S is more electronegative than Te is. In H2SO3, thus, dissociation of H+ would be smoother.

So, H2SO3's got high Ka.

HCH3SO2 is more acid than HCH3CO2. Since S is more electronegative than C. So, HCH3SO2 is a high Ka.

HClO2 is more acid than HClO. Since in HClO2, after the donation of H+ ion, the negative charge is set by two oxygen atoms, while in HClO, only one oxygen atom stabilizes the negative charge.

So, HClO2 is a high Ka

Explanation:

Molar mass of AlCl3 = 133.34g/mol

Moles of AlCl3 used

= 20.0g / (133.34g/mol) = 0.150mol

Mole Ratio of AlCl3 to Cl2 = 2 : 3,

Moles of Cl2 produced

= 0.150mol * (3/2) = 0.225mol

We know that 1 mole of any gas has

6.023 * 10²³ molecules.

Hence, number of molecules in Cl2

= 0.225mol * (6.023 * 10²³/mol)

= 1.35 * 10²³ molecules. (C)

Answer:

oxidizer: one used to support the combustion of a rocket propellant

word: a single distinct meaningful element of speech or writing

Explanation: