what problems can chemistry solve?

Answer:

See figure 1 and figure 2

Explanation:

We can analyze each structure:

A. Structure of 1,4-hexanediamine

For this molecule, we must start with a six-carbon chain. Since, in the name of the molecule we have the prefix "hex", then we have to name the carbons. The first carbon will be the one on the right and the sixth on the left. Finally, we must place two amino groups on carbons 1 and 4 (See figure 1).

B. Draw the structure of 2,4-difluoroaniline

For this molecule, we must start with the aniline molecule. In this molecule, we have an amino group attached to a benzene ring. Carbon number 1 will be the carbon that is attached to the amino group, carbon number 2 must be placed in a clockwise direction. Finally, we must place two fluorine atoms on carbons 2 and 4 (See figure 2).

Answer:

Second order

Explanation:

Given that:

When the reaction A → B + C is studied, a plot 1/[A]t vs. time gives a straight line with a positive slope.

From the integration method for the second order of reaction.

Suppose that:

rate = k₂[A]²

∴

[tex]\dfrac{1}{A}=\dfrac{1}{A_0}+k_2t[/tex]

Therefore, a plot of the linear function [tex]\dfrac{1}{A}[/tex] versus t will be linear with a positive slope k₂ and the intercept on the concentration axis will be [tex]\dfrac{1}{A_o}[/tex]

The linear plot for a second order reaction can be seen in theimage attached below.

Answer:

[tex]m_{solute}=9.19gKClO_3[/tex]

Explanation:

Hello,

In this case, since the molarity is defined as:

[tex]M=\frac{mol_{solute}}{V_{solution}}[/tex]

Whereas the volume of the solution is in liters, we first compute the moles of solute which in this case is the potassium chlorate:

[tex]mol_{solute}=150mL*\frac{1L}{1000mL}*0.50molKClO_3/L \\\\mol_{solute}=0.075molKClO_3[/tex]

Then, by using its molar mass of 122.55 g/mol, we compute the required mass as follows:

[tex]m_{solute}=0.075molKClO_3*\frac{122.55gKClO_3}{1molKClO_3} \\\\m_{solute}=9.19gKClO_3[/tex]

Regards.

Answer:

The 99.68% of the aspirin is present in the neutral form

Explanation:

Aspirin, Acetylsalicylic acid, is a weak acid with pKa = 3.5

Using Henderson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] is the ionized form and HA the neutral form of the acid

Replacing with a pH of stomach of 1.0:

1.0 = 3.5 + log [A⁻] / [HA]

-2.5 = log [A⁻] / [HA]

3.16x10⁻³ = [A⁻] / [HA] (1)

A 100% of aspirin is = [A⁻] + [HA]

100 = [A⁻] + [HA] (2)

Replacing (2) in (1)

3.16x10⁻³ = 100 - [HA] / [HA]

3.16x10⁻³[HA] = 100 - [HA]

1.00316 [HA] = 100

[HA] = 99.68%

Answer:

6 sig figs

Explanation:

sig figs are numbers that are more than 0, but in this case, after the decimal, the 0's at the end count as sig figs as well

There are 6 significant numbers in 31.1100.

If there is no decimal point in the figures then it will be 4 but since there is a decimal point then it is 6 significant figures.

Answer:

This is an exothermic reaction.

Explanation:

You can calculate the reaction using the calculation below:

ΔH reac=  3(413Kj/mol) +358Kj/mol +467 Kj/mol +1070 kj/mol = 3134 kj/mol

ΔH prod = 3(413 kj/mol) + 347 kj/mol + 358kj/mol +467kj/mol +745 kj/mol = 3156kj/mol

ΔH = 3134 kj/mol - 3156kj/mol = -22 Kj/mol

Negative results indicate an exothermic reaction.

An image of the reaction is attached below.

The heat of the reaction has been -22 kJ/mol. The negative sign has been the indication of the exothermic reaction.

The heat of reaction has been given as the amount of energy absorbed or released by the system to form the products.

The heat of reaction has been given by:

[tex]\Delta H=\Delta H_{reactant}-\Delta H_{product}[/tex]

The heat of reaction has been calculated based on the bond energies. The energy constituent by each bond in the reactant has been the heat of the reactant, and the energy of product has been the heat of product.

The reactant molecules have been [tex]\rm CH_3OH[/tex] and [tex]\rm C\equiv O[/tex].

The bond energy of the reactant has been:

[tex]\Delta H_{reactant}=3\;\times \;\text {C-H}\;+\;\text{C-O + O-H}+\;\text C\equiv \text O\\ \Delta H_{reactant}=3\;\times \;413\;+\;358+467+1070\;\text{kJ/mol}\\ \Delta H_{reactant}=3134\;\text{kJ/mol}[/tex]

The heat of reactant has been 3134 kJ/mol.

The product molecule has been [tex]\rm CH_3COOH[/tex]

The bond energy of the product has been:

[tex]\Delta H_{product}=3\;\times \;\text {C-H}\;+\;\text{C-O + O-H +\;C-C}+\;\text C=\text O\\\Delta H_{reactant}=3\;\times \;413\;+\;358+467+\;347\;+\;745\;\text{kJ/mol}\\\Delta H_{reactant}=3156\;\text{kJ/mol}[/tex]

The heat of product has been 3156 kJ/mol.

The heat of reaction has been given as:

[tex]\Delta H=\Delta H_{reactant}-\Delta H_{product}\\ \Delta H=3134-3156\;\text{kJ/mol}\\ \Delta H=-22\;\rm kJ/mol[/tex]

The heat of the reaction has been -22 kJ/mol. The negative sign has been the indication of the exothermic reaction.

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Answer:

I think the teacher was supposed to tell u the answer to that

Answer:

8.34 moles

Explanation:

We are given 8.34 moles.

We need to find moles: 8.34

Answer:

THE MASS OF THE SAMPLE IS 25.37 g

Explanation:

Using PV = m RT / Mm

P = 0.945 atm

V = 1550 mL = 1.55 L

R = 0.082

T = 50 C

m = unknown

Mm = molar mass = 35.5 * 2 = 71 g/mol

Re-arranging the formula by making m the subject of the equation, we have:

m = PV Mm / RT

m = 0.945 * 1.55 * 71 / 0.082 * 50

m = 103.99725 / 4.1

m = 25.37 g

The mass of the sample is therefore 25.37 g

Answer:

Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions. Because the molecules are not moving, they're not able to form as many hydrogen bonds with other water molecules. Ice is a unique substance because it is solid-state — ice — is less dense than its liquid state. Because of this property, ice floats in water. Physical properties are characteristics of a substance. They do not change. Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions.

Answer:

Xenon

Explanation:

Step 1: Given data

Step 2: Convert the temperature to Kelvin

K = °C + 273.15 = 100.0°C + 273.15 = 373.2 K

Step 3: Calculate the number of moles (n)

We will use the ideal gas equation.

P × V = n × R × T

n = P × V / R × T

n = 1.00 atm × 0.335 L / (0.0821 atm.L/mol.K) × 373.2 K

n = 0.0109 mol

Step 4: Calculate the molar mass of the gas

M = 1.44 g / 0.0109 mol = 132 g/mol

Step 5: Identify the gas

The gas with a molar mass of about 132 g/mol is xenon.

The gas with a molar mass of 132.11g/mol is Xenon. Hence the unknown gas is Xenon

Using the ideal gas equation

[tex]PV=nRT\\n=\frac{PV}{RT}[/tex]

R is the Boltzmann constant = 8.31

V is the volume of the gas = 0.355L

P is the pressure = 1.00atm

T is the temperature of the gas = 100.0°C = 373K

To get the unknown gas, we need to first get the number of moles of gas:

[tex]n=\frac{1.0\times 0.335}{0.0831 \times 373}\\n=0.0109 moles[/tex]

Get the molar mass of the element;

[tex]n=\frac{m}{M}\\0.0109=\frac{1.44}{M}\\M=\frac{1.44}{0.0109}\\M= 132.11g/mol[/tex]

The gas with a molar mass of 132.11g/mol is Xenon. Hence the unknown gas is Xenon

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Answer:

9.8 × 10^21

Explanation:

Equation of the reaction;

Cd(s) + Ni^2+(aq) ----> Cd^2+(aq) + Ni(s)

E°cell= E°cathode - E°anode

E°cathode= -0.25 V

E°anode = -0.40 V

E°cell= -0.25 - (-0.40)

E°cell = 0.65 V

∆G= -nFE°cell

∆G= -(2 × 96500 × 0.65)

∆G = -125450 J

From;

∆G= -RTlnK

lnK = ∆G/-RT

K= e^∆G/-RT

K= e^-[-(125450/8.314 × 298)]

K= 9.78 × 10^21

Answer:

- Communication between scientists increased.

- Technological advancements were made.

Explanation:

The complete question is

Which answer choices correctly describe why the number of known elements more than doubled by 1861?

Select all that apply.

 -  Metalworkers began using new metals.

- Communication between scientists increased.

- The American Civil War started.

- Technological advancements were made.

Technological advancement allowed more elements to be properly analysed and classified, and knowledge sharing between scientist by means of communication made it possible for the known number of elements to double by 1861

Answer:

[tex]r_B=k[A][B]^3[/tex]

Explanation:

Hello,

In this case, in order to represent the rate disappearance of B, we need to consider the rate law as:

[tex]r_B=k[A][B]^3[/tex]

Whereas k is the rate constant the third power corresponds to B's stoichiometric coefficient as well as the concentrations of A and B because they are involved in the overall rate too.

Regards.

Answer:

The principal quantum number for the outermost electrons in a Te atom in the ground state is 5

Explanation:

In quantum chemistry, the region of maximum probability of where an electron is located is sometimes referred to as cloud or orbital.

The principal quantum number is used to express the state of an electron

The principal quantum number for the outermost electrons in a Te atom in the ground state is 5

The atomic number of Tellurium Te is Kr 4d¹⁰ 5s² 5p⁴

so quantum no is 5

Answer:

The average persons requires 75000 breaths to exhale 1.0 Kg of fat

Explanation:

Note: The question is incomplete. The complete question is given below:

"The human body burns glucose (C6H1206) for energy according to this chemical reaction:

C6H1206 + 602----> 6CO2 + 6H20

The products of the reaction are carbon dioxide (CO2) and water (H20). Interestingly, all of the carbon dioxide and much of the water exits the body through the lungs: on every breath, the average person exhales 500 mL of air, which is typically enriched to 4% CO2 and 5% water vapor by volume. In short, when a person loses weight by dieting, the weight that is lost actually departs his body as a gas, every time he exhales. Each kilogram of body fat lost requires exhaling about 3.0 kg of carbon dioxide. Calculate how many breaths it takes an average person to "exhale" 1.00 kg of fat. Round your answer to the nearest thousand. You'll need to know that the density of CO2 is 2.0 kg/m³”.

Volume of air exhaled on average per breath = 500 mL

Volume of CO2 exhaled per breath = 4/100 × 500 = 20 mL

Since, 1000000 mL = 1 m³;

20 mL = 0.00002 m³

3.0 kg of CO2 is exhaled per Kg of fat.

Density of CO2 = 2.0 Kg/m³

Volume = mass/density

Volume of 3.0 Kg CO2 = 3.0/2.0 = 1.5 m³

Number of breaths that will have a volume of 1.5 m³ = 1.5/0.00002 = 75000 breaths.

Answer:

volume = 15

density = 10

Explanation:

mass = 150 grams

volume = 45 - 20 = 15

density = mass / volume

density = 150 / 15 = 10

Answer:

D

Explanation:

Because jwbahaggagqhhwjwjja

Answer:

(CH3)3CCH2Br

Explanation:

This reaction proceeds by the following mechanism;

First, irradiation with light of appropriate frequency leads to the homolytic fission of the bromine molecule to yield two bromine free radicals. This is the initiation step of the reaction.

The free radical now attacks one of the -CH3 groups in neopentane leading to the formation of (CH3)3CCH2Br.

Answer:

Direct a magnet towards the mixture of iron and sand. You can observe that only the iron filling is attracted to the magnet and will come in contact with it. Therefore, after this process, you'll be left with iron filling on the surface of the magnet whereas the sand particles are left on the dish

To separate a mixture of iron filings and sand, using the physical property of iron is by using a magnet because a magnet attracts iron, but not sand.

Physical properties are those properties that can be seen by seeing an object or a substance. These properties do not change with the change in the composition of matter.

Physical properties are appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.

Magnetic properties are the property in which the object attracts to magnets and or iron-containing substances, here it can be used to separate sand and iron.

Thus, using a magnet and the magnetic property of iron—which attracts iron but not sand—one can separate a combination of iron filings and sand.

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Answer:

C₁₀H₁₂

Explanation:

90.8% of basketane (Hydrocarbon, contains only C and H) is Carbon, and 100-90.8 = 9.2% of the mass is hydrogen.

The molar mass is between 130-140g/mol, That means the moles of Carbon (Using its molar mass, 12.01g/mol) that are in basketane are between:

140g/mol /12.01g/mol *90.8%= 10.58 moles of C.

130g/mol / 12.01g/mol *90.8%= 9.83 moles of C.

As the moles of carbon must be given in a whole number, There are 10 moles of Carbon.

10 moles C * (12.01g / mol) = 120.1g/mol that are 90.8% of the molar mass. Molar mass of basketane is:

100% * (120.1g/mol / 90.8%) =

132.3g/mol.

The part of the molar mass due hydrogen must be:

132.3 g/mol - 120.1g/mol = 12.2 g/mol

As molar mass of hydrogen is 1g/mol, the moles of hydrogen are 12

And molecular formula is:

Answer:

b

Explanation:

The correct answer would be requiring individuals to complete specific types of work.

A question of how to produce deals with the processes of production itself. There are several small processes that eventually aggregate together to lead to the production of goods or services. Some of these small processes will definitely require that individuals within the production unit complete specific types of work.

The option of growing corn instead of potatoes and producing more capital goods and fewer consumer products address what to produce while the option of selling natural resources to other countries has to do with for whom to produce.

Correct option: b

Answer:

2NaCl > Cl2 + 2Na

Explanation:

2 moles of sodium chloride is irreversible to chlorine gas plus 2 moles of solid sodium

Solid sodium chloride decomposes into chlorine gas and solid sodium balanced chemical equation will be 2NaCl → [tex]2 Na^{+} + 2Cl^{-}[/tex].

An equation with equal proportions of each kind of atom from both ends of the arrow would be called a balanced chemical reaction. A written symbolic description of a chemical reaction will be known as a chemical equation. The reactant chemical(s) were listed on the left, while the product chemical(s) were listed on the right.

Chemical equation is just the presentation of a chemical reaction using symbols and equations for the ingredients.

Solid sodium chloride decomposes into chlorine gas and solid sodium balanced chemical equation will be 2NaCl → [tex]2 Na^{+} + 2Cl^{-}[/tex].

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Answer:

Hydrogen gas

Explanation:

K +H2O=KOH+ H2

Test for hydrogen gas:

Light a splint and put it in the smoke present. If it makes a pop sound, that means hydrogen is present

Answer:

-2.79 × 10³ cal

Explanation:

Step 1: Given data

Step 2: Calculate the heat required to freeze 35.0 g of water

We have 35.0 g of liquid water and we want to freeze it, that is, to convert it in 35.0 g of ice (solid water), at 0 °C (melting point). We can calculate the heat (Q) that must be released using the following expression.

Q = L × m

Q = -79.7 cal/g × 35.0 g

Q = -2.79 × 10³ cal

The heat in calories required to freeze 35.0g of water of water is 2.79 × 10³ cal.

Q = L × m

Where;

According to this question;

Q = L × m

Q = -79.7 cal/g × 35.0 g

Q = -2.79 × 10³ calories

Therefore, the heat in calories required to freeze 35.0g of water of water is 2.79 × 10³ cal.

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Answer:

Exposure of 2-methyl-2-butene to oxymercuration-demercuration conditions provides 2-methyl-2-butanol.

Explanation:

Please see the attachments below

Answer:

75.15 g/mol

Explanation:

First, let us look at the equation of reaction;

[tex]NaOH + HAA --> NaAA + H_2O[/tex]

From the balanced equation of reaction, 1 mole of NaOH is required to completely neutralize 1 mole of HAA.

Recall that: mole = molarity x volume.

Therefore, 27.50 mL, 0.120 M NaOH = 0.0275 x 0.120 = 0.0033 moles

0.0033 mole of NaOH will therefore requires 0.0033 moles of HAA for complete neutralization.

In order to find the molar mass of the unknown amino acid, recall that:

mole = mass/molar mass, hence, molar mass = mass/mole.

Therefore, molar mass of HAA = 0.248/0.0033 = 75.15 g/mol