A team of engineers has decided to design a new shoe for people suffering from a painful foot condition. Each of the following tasks is necessary for the engineers to undertake during the beginning phase of the project except which?

A. Have subjects wear the shoes in an experimental trial to see if symptoms improve
B. Do research on orthopedic shoes that have already been designed for this condition
C. Estimate the price potential consumers would be willing to pay for this product
D. Look into the available materials and weigh the advantages and disadvantages of each

Answer:

PH of the weak acid: approximately 2.513.

PH of the buffer solution: approximately 4.495.

Explanation:

The Ka value of benzoic acid is much smaller than 1. Benzoic acid will dissociate but only partially when dissolved in water. Construct a RICE table for this process. Let the equilibrium of [tex]\rm H^{+}[/tex] be [tex]x\; \rm mol\cdot L^{-1}[/tex]. Note that [tex]x \ge 0[/tex].

[tex]\displaystyle \begin{array}{c|ccccc}\textbf{R}&\mathrm{C_6H_5COOH} & \rightleftharpoons & \mathrm{C_6H_5COO^{-}} & + &\mathrm{H^{+}}\\\textbf{I} & 0.015 & & 0 & & 0\\\textbf{C} & -x & & +x & & +x\\\textbf{E} & 0.015-x & & x & & x\end{array}[/tex]

[tex]\displaystyle \frac{[\mathrm{C_6H_5COO^{-}}]\cdot [\mathrm{H^{+}}]}{[\mathrm{C_6H_5COOH}]} = \mathrm{pK}_{a}[/tex].

[tex]\displaystyle \frac{x^{2}}{0.015 - x} = 6.4\times 10^{-5}[/tex].

Solve this quadratic equation for [tex]x[/tex]:

[tex]x^{2}+ 6.4\times 10^{-5}\;x - 6.4\times 10^{-5}\times 0.150 = 0[/tex].

[tex]\displaystyle x = \frac{-6.4\times 10^{-5} \pm \sqrt{(6.4\times 10^{-5})^{2} - 4\times (- 6.4\times 10^{-5}\times 0.150)}}{2}[/tex].

Take only the non-negative root. [tex]x \approx 0.00306655[/tex].

[tex]\rm [H^{+}] = 0.00306655\; mol\cdot L^{-1}[/tex].

[tex]\displaystyle \mathrm{pH} = -\log_{10}{[\mathrm{H^{+}}]} = 2.513[/tex].

Each benzoic acid contains only one carboxyl group [tex]\mathrm{-COOH}[/tex]. Benzoic acid is thus a monoprotic acid. Each mole of the acid will react with only one mole of [tex]\rm NaOH[/tex]. The 100 mL solution initially contains [tex]1.50\times 10^{-3}[/tex] moles of benzoic acid. The [tex]1\times 10^{-3}[/tex] moles of [tex]\rm NaOH[/tex] will neutralize only part of the acid. The solution will eventually contain [tex]1\times 10^{-3}[/tex] moles of [tex]\mathrm{C_6H_5COO^{-}}[/tex] (from the salt [tex]\mathrm{C_6H_5COONa}[/tex]) and [tex]0.50\times 10^{-3}[/tex] moles of [tex]\mathrm{C_6H_3COOH}[/tex].

Both the acid [tex]\mathrm{C_6H_5COOH}[/tex] and the conjugate base of the acid [tex]\mathrm{C_6H_5COO^{-}}[/tex] exist in large amounts in the solution. Apply the Henderson-Hasselbalch equation for weak acid buffers to find the pH of this buffer solution.

[tex]\mathrm{pK}_{a} = -\log_{10}{\mathrm{K}_{a}} \approx 4.19382[/tex] for benzoic acid.

[tex]\begin{aligned}\mathrm{pH} &= \mathrm{pK}_{a} + \log{\frac{{[\text{Conjugate Base}]}}{[\text{Weak Acid}]}} \\ &= \mathrm{pK}_{a} + \log{\frac{{[\mathrm{C_6H_5COO^{-}}]}}{[\mathrm{C_6H_5COOH}]}}\\ &= 4.19382 + \log{\frac{0.01}{0.005}}\\ &\approx 4.495 \end{aligned}[/tex].

Answer:

- 0.8217°C.

Explanation:

ΔTf = Kf.m,

ΔTf is the depression in the freezing point.

Kf is the molal freezing point constant for water (Kf = -1.86 °C/m).

m is the molality of glucose.

Molality (m) is the no. of moles of solute in 1.0 kg of solvent.

∴ m = (mass/molar mass) of glucose/(mass of water (kg))

∴ m = (19.5 g/180.156 g/mol)/(0.245 kg) = 0.4418 m.

∴ ΔTf = Kf.m = (-1.86 °C/m)(0.4418 m) = - 0.8217°C.

Answer:

the work the simple machine performs (second choice)

Answer:Troposphere, Stratosphere, Mesosphere and Thermosphere

Explanation:

a. The quantity of heat in Joules is equal to 1,305.832 Joules.

b. The quantity of heat in Calories is equal to 312.10 Cal.

Given the following data:

Scientific data:

To determine the quantity of heat in Joules:

Mathematically, quantity of heat is given by the formula;

[tex]Q=mc\theta[/tex]

Where:

Substituting the given parameters into the formula, we have;

[tex]Q = 28.4 \times 2.09 \times (-1.0 -[-23.0])\\\\Q=59.356 \times (-1.0+23.0)\\\\Q=59.356 \times22[/tex]

Quantity of heat, Q = 1,305.832 Joules.

In Calories:

[tex]Calories =\frac{1305.832}{4.184}[/tex]

Calories = 312.10 Cal.

Read more: https://brainly.com/question/2834175

The answer is:

When the pressure that a gas exerts  on a sealed container changes from

22.5 psi to 19.86 psi, the  temperature changes from 110°C to

65.9°C.

To calculate which is the last pressure, we need to use Gay-Lussac's law.

The Gay-Lussac's Law states that when the volume is kept constant, the temperature (absolute temperature) and the pressure are proportional.

The Gay-Lussac's equation states that:

[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]

We are given the following information:

We need to remember that since the temperatures are given in Celsius degrees, we need to convert it to Kelvin (absolute temperature) before use the equation, so:

[tex]P_1=22.5Psi\\T_1=110\°C=110\°C+273.15=383.15K\\T_1=65.9\°C=65\°C+273.15=338.15K[/tex]

Now, calculating we have:

[tex]\frac{P_1}{T_1}*(T_2)=P_2\\\\P_2=\frac{P_1}{T_1}*(T_2)=\frac{22.5Psi}{383.15}*338.15=19.86Psi[/tex]

Hence, the final pressure is equal to 19.86 Psi.

Have a nice day!

Answer:

The final pressure at 65.9°C is 19.91 psi.

Explanation:

To calculate the final pressure of the system, we use the equation given by Gay-Lussac Law.

This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]  (at constant Volume)

where,

[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.

[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.

We are given:

[tex]P_1=22.5 psi\\T_1=110^oC=383.15 K\\P_2=?\\T_2=65.9^oC=339.05 K[/tex]

Putting values in above equation, we get:

[tex]\frac{22.5 psi}{383.15 K}=\frac{p_2}{339.05 K}[/tex]

[tex]P_2=\frac{22.5 psi}{383.15 K}\times 339.05 K=19.91 psi[/tex]

The final pressure at 65.9°C is 19.91 psi.

The percent error in the worker's measurement, when compared to the manufacturer's specifications, is 1.39%.

To calculate the percent error in the worker's measurement, we need to compare the measured value to the accepted value given by the manufacturer's specifications. The formula to determine percent error is:

[tex]Percent\ Error = |\frac{Measured\ Value\ -\ True\ Value}{True\ Value}| \times 100\%[/tex]

In this case:

Applying the values to the formula, we get:

[tex]Percent\ Error = |\frac{14.6 cm - 14.4 cm}{14.4 cm}| \times 100\% = |\frac{0.2 cm}{14.4 cm}| \times 100\% = 0.0139 \times 100\% \\ = 1.39\%[/tex]

Therefore, the percent error in the worker's measurement is 1.39%.

Answer:

51.88 grams

Explanation:

make it in ratio form

Al=27×2=54.

54:48

(54/102)×98

=51.88 grams

O=16×3=48

(48/102)×98

=46.12 grams

Answer:

Lithium (Li)

Explanation:

Lithium had the lowest ionization energy value because it has a low effective nuclear charge and a large radius

Answer:

lithium

Explanation:

Answer:

- motors that run on electricity

- tires that improve gas mileage

Explanation:

The transportation is a major polluter of the air. The big problem with it is that it is necessary for the humans to be able to live and function properly, as the trade is happening through it, thus it is crucial for the economy. In order to stop or reduce the negative impact on the air quality, there are some solutions which can help. The motors that can run on electricity are an excellent method, as the production of electricity is not polluting the are as the fossil fuels are. The only problem is that this type of motors are still very expensive, so once their price is on pair with the combustion motors they can be used. Tires that are able to increase the efficiency of the transportation means can also be useful, as they will be able to reduce the amount of pollutants released into the atmosphere, because the transportation will use less fossil fuels for the same mileage.

Answer:

Explanation:

Under the sector of transportation passenger vehicles are the major contributor to the pollution. Emission from cars and two-wheeler is the leading cause of increasing level of carbon dioxide, sulfur content and other greenhouse gases.

Solution to this problem include:

Answer:

Explanation:

Coordinate covalent bonds differs from other types of covalent bonds in that the two atoms bonds in such a way that one member of the bonding pair supplies both electrons to be shared. In normal covalent bonds, both atoms supplies the electrons to be shared.

This type of bond is used to join two covalent compounds together. They can also be used in joining protons to neutral covalent molecules together.

Final answer:

Once established, coordinate covalent bonds are indistinguishable in strength and function from other covalent bonds.

Explanation:

The question asks about the difference between a coordinate covalent bond and other covalent bonds once they are formed. A coordinate covalent bond is a type of covalent bond where a single atom provides a pair of

electrons for the bond, while a regular covalent bond involves each atom contributing one electron to the shared pair. A classic example of a coordinate covalent bond is found in the carbon monoxide molecule (CO), where one of the three bonds between carbon and oxygen is a coordinate covalent bond because oxygen donates both electrons for that bond.

However, once formed, a coordinate covalent bond is just as strong and behaves in the same way as any other covalent bond.

Atoms typically form a characteristic number of covalent bonds that can include double bonds or triple bonds, as depicted in Lewis electron dot diagrams. Whether a bond is a coordinate covalent bond or not does not affect the eventual strength or final properties of the bond.

Answer:

So, we rely on radiometric dating to calculate their ages. Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.

Explanation:

radiometric dating is a very accurate way to date the Earth.We know it is accurate because radiometric dating is based on the radioactive decay of unstable isotopes. When an unstable Uranium (U) isotope decays, it turns into an isotope of the element Lead (Pb).

Answer:

The radioactive dating method is one of the efficiently used methods in order to calculate the age of the rocks, meteorites, fossils and various other objects, depending upon the rate at which radioactive isotopes decay. In this method, an unstable element changes into a stable one, releasing some amount of radiation and losing a certain amount of energy.

This is efficient in determining the age of the earth. The earth is comprised of rocks that are present from the time of its formation. These rocks can be dated using this method and the approximate age of the rock is evaluated.

The Uranium-Lead dating (²³⁸U-²⁰⁶Pb) method was used to date the smaller zircon crystals of Australia that are about 4.4 billion years old. The half-life of U-238 is approximately 4.5 billion years, which shows that these are one of the oldest rocks on earth and helps in understanding how old the earth is.

Half-life is defined as the time required by a radioactive isotope to decay half of its atoms.

So the radioactive dating method is one of the common method gives the approximate age of the earth.

Answer:

Aluminum

Explanation:

An atom of any elements has an outer electron and a proton and neutron located in the nucleus . The proton and neutron found in the nucleus of an atom determine the mass number of an element. The mass number of an element is the sum of the proton(atomic number) and the neutron number.

Mathematically,

Mass number = proton number(atomic number) + neutron number

Therefore,

neutrons number = mass number - proton number

Aluminium has the highest neutron  

neutron = 27 - 13 = 14

Neutron of aluminium = 14

Final answer:

Aluminum, with a mass number of 27 and an atomic number of 13, has the most neutrons in its nucleus among the given elements, totaling 14 neutrons.

Explanation:

To determine which element has the most neutrons in its nucleus, we need to subtract the atomic number from the mass number for each element. The atomic number represents the number of protons, and the mass number is the sum of protons and neutrons in the nucleus.

Aluminum has a mass number of 27 and an atomic number of 13, resulting in 27 - 13 = 14 neutrons.

Nitrogen has a mass number of 14 and an atomic number of 7, resulting in 14 - 7 = 7 neutrons.

Helium has a mass number of 4 and an atomic number of 2, resulting in 4 - 2 = 2 neutrons.

Fluorine has a mass number of 19 and an atomic number of 9, resulting in 19 - 9 = 10 neutrons.

Comparing the number of neutrons calculated for each element, we can see that Aluminum has the most neutrons in its nucleus.

Answer:

B) C2

Explanation:

C2 is oxygen and oxygen is an element :)

Answer:

A is water

B is an oxygen molecule

C is an organic compound

The answer is B

The balanced chemical equation for photosynthesis is 6CO2(g) + 6H2O(l) → C6H12O6(s) + 6O2(g), with water being the limiting reactant and carbon dioxide in excess. The mass of excess CO2 and the mass of glucose produced is determined by stoichiometric calculations.

The balanced chemical equation for photosynthesis is 6CO2(g) + 6H2O(l) → C6H12O6(s) + 6O2(g). This shows that carbon dioxide (CO2) and water (H2O) react to form glucose (C6H12O6) and oxygen (O2). To find the limiting reactant, you convert the masses given for CO2 and H2O to moles using their respective molar masses (44.01 g/mol for CO2 and 18.02 g/mol for H2O). You would find that water is the limiting reactant because there are fewer moles of H2O than CO2 when compared to the stoichiometric coefficients in the balanced equation.

To find the excess reactant, subtract the amount of CO2 that would react with the available H2O from the initial amount of CO2 to determine the mass in excess. For the mass of glucose produced, use the mole ratio from the balanced equation, multiplied by the number of moles of the limiting reactant and then by the molar mass of glucose (180.16 g/mol).

Answer:

1.15 molecules

Explanation:

To get to molecules, you need to first convert grams into moles, then moles into molecules.

345g of water x [tex]\frac{1 mol }{18.02g}[/tex]

This will get you the moles of water. (The number 18.02 came form the molar mass of water which is H2O)

I MOLE EQUALS AVOGADRO'S NUMBER

19.15 mol of water x[tex]\frac{6.022*10^{23}molecules }{1 mol}[/tex]

= 1.15

Answer:

There are [tex]1.1542\times 10^{25} [/tex] molecules of water are in 345 grams.

Explanation:

[tex]n=\frac{m}{M}[/tex]

[tex]N=n\times N_A[/tex]

Where:

m = mass of compound

M = Molar mass of compound

N = Number of particles / atoms/ molecules

n = Number of moles

[tex]N_A=6.022\times 10^{23} mol^{-1}[/tex] = Avogadro's number

Mass of water = m =  345 g

Molar mas of water = M = 18 g/mol

[tex]n=\frac{345 g}{18 g/mol}=19.167 mol[/tex]

Number of molecules of water = N

[tex]N=19.167 mol\times 6.022\times 10^{23}mol^{-1}[/tex]

[tex]N = 1.1542\times 10^{25} molecules[/tex]

There are [tex]1.1542\times 10^{25} [/tex] molecules of water are in 345 grams.

Answer:

PLATO: Polar, Tetrahedral, NonPolar

Explanation:

Halogens are in Group 17 of the periodic table because they have seven valence electrons, making them highly reactive as they seek one more electron to achieve a full octet. Their ability to readily form singly negative ions and salts when reacting with metals further characterizes their group placement.

Halogens are kept in Group 17 (also known as Group VIIA) of the modern periodic table because of their distinctive chemical properties. Each halogen has seven valence electrons (a p⁵ configuration in their outermost p subshell), which is just one electron short of completing their outer shell. Thus, they are highly reactive, as they need only one additional electron to achieve a stable, noble gas electron configuration.

The reactivity of halogens also allows them to form singly negative ions, such as Cl-, by accepting an extra electron into the vacancy in their outer p subshell. This contrasts with alkali metals that reside in Group 1, which easily give up their single s electron to form singly positive ions like Na+. Because halogens readily combine with metals to form salts, such as sodium chloride, they are known as "salt-forming" or halogens.

Moreover, the physical states of halogens at room temperature are diverse: chlorine is a gas, bromine is a liquid, and iodine and astatine are solids. This variation doesn't affect their placement in Group 17, which is based on their shared electronic configuration and chemical properties.

Answer:

the answer is B

Explanation:

reactants are on the left because they are the ones reacting. products are on the right because they are the final products.

Answer:

An endothermic reaction is identified by noting the drop in temperature in the system.

Explanation:

An endothermic reaction occurs by absorbing heat energy from the environment( apparatus and solution). Once the energy in the surrounding reduces the temperature drops. The energy absorbed is used to form new bonds. The energy absorbed is directly proportional to the temperature drop.

Answer:

An endothermic reaction absorbs heat from its surroundings.  

Explanation:

An example is the reaction of acetic acid with baking soda.

Three ways to tell if a reaction is endothermic:

Answer:

They present 1 electron

Answer:

heat is supplied to the reaction

Answer:

The Δ symbol in a chemical equation means energy in form of heat is provided to the system.

Explanation:

When the Δ symbol is above or under the arrow of a chemical reaction representation it is indicating that the reagents must be heated to obtain the products. i.e. is representing an endothermic reaction in which energy must be provided to the system for the reaction to occur.

Answer:

Acid from abandoned mines- D.

Answer:

Water from a sewage treatment plant

Explanation:

Water from a sewage treatment plant is an example of point-source pollution.

Answer:

On a power source such as a battery, the anode is labelled with a + (plus)

The cathode on the other side is labelled with a - (minus)

When ionic compounds ionize, they produce both positive and negative ions.

Anion- This is a negatively charged ion for example chloride ion (Cl⁻)

Cation- This is a positively charged ion for example sodium ion (Na⁺)

The morality, or molarity, of a 2.50 L solution containing 1.85 mol of anhydrous sodium tetraborate is calculated by dividing the amount of solute by the volume, yielding a concentration of 0.74 M.

The morality of a 2.50 L solution containing 1.85 mol of anhydrous sodium tetraborate refers to its molar concentration, which is expressed in moles per liter (mol/L). To find the morality, also known as molarity, you would divide the number of moles of solute by the volume of the solution in liters.

Molarity (M) = moles of solute / volume of solution in liters

Therefore, the molarity of the sodium tetraborate solution is:

M = 1.85 mol / 2.50 L

M = 0.74 M

Answer:

0.823 g.

Explanation:

M = (no. of moles of K⁺)/(Volume of the solution (L).

∵ no. of moles of K⁺ = (mass/molar mass) of K⁺.

∴ M = (mass/molar mass) of K⁺/(Volume of the solution (L).

M = 0.0044 M.

Volume of the solution = 4785.0 mL = 4.785 L.

mass of K⁺ = ??? g.

molar mass of K⁺ = 39.01 g/mol.

∴ mass of K⁺ = (M)((molar mass of K⁺)(volume of the solution (L)) = (0.0044 M)(39.10 g/mol)(4.785 L) = 0.823 g.

Answer:

Place two of them as reactants.

Explanation:

1) N₂(g ) + O₂(g) → 2NO(g).

2) 2NO(g )+ O₂(g) → 2NO₂(g).

N₂(g ) + 2O₂(g) → 2NO₂(g).

NO is cancelled out because there is one in each equation in the products side in eq. 1 and in oriduct side in eq. 2.

So, we place two of oxygen as reactants.

Answer:

Place two of them as reactants

Explanation:

To express 0.026890 in scientific notation, it is written as 2.6890 x [tex]10^{-2}[/tex].

Express the following number in scientific notation:

0.026890 = 2.6890 x [tex]10^{-2}[/tex]

Scientific notation is a way to represent very large or very small numbers more concisely. It is written as a number between 1 and 10 multiplied by a power of 10.

Answer:

3.85L

Explanation:

Given parameters:

Initial pressure P₁ = 15psi (1psi = 52mmHg)

                       converting to mmHg gives (15x52)mmHg = 780mmHg

Initial volume V₁ = 7.0L

Final pressure P₂ = 1420torr= 1420mmHg

Unknown:

Final volume V₂ = ?

Condition of the process: Constant temperature

Solution

To solve this problem, we simply apply Boyle's law. Boyle's law states that "The volume of a given mass of gas varies inversely as the pressure changes, if the temperature is constant".

It is mathematically expressed as ;

                 P₁V₁ = P₂V₂

The unknown here is V₂ and we simply express it as the subject of the formula:

                V₂ = [tex]\frac{P_{1} V_{1} }{P_{2} }[/tex]

         V₂ = [tex]\frac{780 x 7 }{1420}[/tex]

          V₂ = [tex]\frac{5460}{1420}[/tex] = 3.85L