Which of the following describes green design?
A. Materials that will fail in a predictable and safe way
B. The use of new engineering technologies in building construction
c. Building structures made of composite materials to make them
safer
D. Materials and design techniques that reduce the negative
environmental impact of a structure

Answer:

9.375

Explanation:

According to the chemical equation, for every 4 moles of gallium, 3 moles of sodium are needed to react.  Set up a ratio using this relationship to solve.

4/3 = 12.5/x

4x = 37.5

x = 9.375

You need 9.375 moles of sulfur.

Answer:

114 grams

Explanation:

3chlorines per compound*38grams=114

Answer:

0.96 mol CO

Explanation:

We simply just use the reaction to help us find this:

[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]

Multiply it out and we get 0.96 as our answer.

Answer:

Option E. 2.04 L

Explanation:

Data obtained from the question include:

Molarity of NaCl = 2.25 M

Mole of NaCl = 4.58 moles

Volume =..?

Molarity is simply defined as the mole of solute per unit litre of the solution. It is represented mathematically as:

Molarity = mole /Volume

With the above formula, we can obtain the volume of the solution as follow:

Molarity = mole /Volume

2.25 = 4.58/volume

Cross multiply

2.25 x volume = 4.58

Divide both side by 2.25

Volume = 4.58/2.25

Volume = 2.04 L

Therefore, the volume of the solution is 2.04 L

Answer:

The correct answer is - 0.570 grams

Explanation:

The balanced chemical reaction is given by

Cu(NO3)2(aq)     + 2NaOH(aq)    -------->    Cu(OH)2(s)      + 2NaNO3(aq)

        1.0 mole            2.0 mole                 1.0 mole          2.0 mole

number of mol of Cu(OH)2,

n = Molarity * Volume

= [tex]35.0*0.167 = 5.845[/tex] millimoles

As clear in the equation, 1 mole of Cu(NO3)2 gives 1 mole of Cu(OH)2 , So, 5.845 millimoles of Cu(NO3)2 will produce 5.845 millimoles of Cu(OH)2

Mass of Cu(OH)2 = number of mol * molar mass

= [tex]97.5*5.845*10^-3[/tex]

= 0.570 grams

Thus, the correct answer is - 0.570 grams

Answer:

W= -11KJ

Explanation:

Given:

volume expands from 28 L to 51 L

pressure =4.9 atm.

We will need to Convert the pressure to Pascal SI

But 1 atm = 101,325 Pa.

Then,

Pressure= (4.9*101323)/1atm = 5*10^5 pa

Then we need to Convert the volumes to cubic meters

But we know that1 m³ = 1,000 L.

V1= 28L * 1m^3/1000L = 0.028m^3

V2=51L × 1m^3 /1000L =0.051m^3

The work done during the expansion of a gas can be calculated as

W= -P(V2-V1)

W= - 5*10^5(0.051m^3 - 0.028m^3)

W= -1.1× 10^4J

Then we can Convert the work to kiloJoule

But1 kJ = 1,000 J.

W= -1.1× 10^4J× 1kj/1000J

= -11KJ

Answer:

14.32g

Explanation:

Initial temperature = 83.8°C

Final temperature = 77.1°C

Temperature change, ΔT = 83.8°C - 77.1°C = 6.7

Heat, H = 167J

Specific heat, c = 1.740J/g °C

m = ?

All these parameters are related with the equation below;

H = mcΔT

m = H / cΔT

m = 167 /  (1.740 * 6.7)

m = 167 / 11.658 = 14.32g

Answer:

alcohol

Explanation:

Since in its chemical structure it presents an amide, amine and aromatic ring group.

What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.

Answer:

THE AMOUNT OF HEAT REQUIRED TO CONVERT ICE FROM -20 C TO STEAM AT 120 C IS 30 946 J OR 30.946 KJ OF HEAT.

Explanation:

Mass = 10 g

To convert 10 g of ice at -20°C to steam at 120°C, the heat involved is:

1. Heat involved in converting the ice from -20 °c to ice at 0 °C:

Heat = mass * specific heat of water solid * change in temperature

heat = 10g * 2.09 J/g°C * ( 0- (-20))

Heat = 10 * 2.09 * 20

heat = 418 J

2. Heat required to convert the ice from 0°C to water at 0°C:

Heat = mass * specific heat of fusion of water solid

Heat = 10 * 333

Heat = 3330 J

3. Heat required to convert water at 0 C to water at 100 C:

Heat = mass * specific heat of water * change in teperature

Heat = 10 * 4.18 * (100 -0)

Heat = 4180 J

4. Heat required to convert water at 100 C to steam at 100 C:

Heat = mass * specific heat of vaporization

Heat = 10 * 2260

Heat = 22600 J

5. Heat required to convert steam from 100 C to steam at 120 C:

Heat = mass * specific heat of water * change in temperature

Heat = 10 * 2.09 * (120 -100)

Heat = 10 * 2.09 * 20

Heat = 418 J

T

he heat required to convert 10 g of ice at -20 C to steam at 120 C is therefore the total of the individual heat of reactions

Total amount of heat = ( 418 J + 3330 J + 4180 J + 22600 J + 418 J)

Total heat =  30946 J

Answer:

0.774g of ethanol

0.970mL of ethanol

Explanation:

Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.

In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).

14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:

0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol

To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:

0.0168moles Ethanol ₓ (46.07g / mol) =

And to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):

0.774g ₓ (1mL / 0.798g) =

Answer:

D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M

Explanation:

Based on the reaction:

PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)

And knowing:

Kc = [PCl₃] [Cl₂] / [PCl₅] = 1.80

When you add PCl₅ into a flask, this gas will react producing PCl₃ and Cl₂ until [PCl₃] [Cl₂] / [PCl₅] = 1.80

This could be written as:

[PCl₃] = X

[Cl₂] = X

[PCl₅] = 0.125M - X

Where X represents the moles of PCl₅ that react, reaction coordinate.

Replacing in Kc expression:

[PCl₃] [Cl₂] / [PCl₅] = 1.80

[X [X] / [0.125 - X] = 1.80

X² = 0.225 - 1.80X

0 = -X² -1.80X + 0.225

Solving for X:

X = -1.9M → False solution, there is no negative concentrations

X = 0.11735M → Right solution.

Replacing, concentrations in equilibrium are:

[PCl₃] = X

[Cl₂] = X

[PCl₅] = 0.125M - X

[PCl₃] = 0.117M

[Cl₂] = 0.117M

[PCl₅] = 0.00765M

And right option is:

Answer:

The unknown compound is a weak acid.

Explanation:

Given that :

a 25 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution.

A buffer region was found around a pH of 3.5. We know that a pH of 3.5 is a weak acid. So, it is likely to be an organic acid

Let assume the solution of the unknown sample to be CH₃COOH

Now :

25 mL of CH₃COOH reacted with 0.115 M of NaOH

The equation for the reaction will be :

CH₃COOH    +    NaOH -----> CH₃COONa + H₂O

at x mole of      0.115y M of

CH₃COOH       NaOH is present

If NaOH was added in excess;

CH₃COOH    +    NaOH -----> CH₃COONa , NaOH will be lost then CH₃COOH    and CH₃COONa will be present

Therefore;

At equilibrium : Only CH₃COONa will be present but if it is above equilibrium NaOH will be present   because the pH will increase due to the presence of the strong base

Answer:

CH4

Explanation:

In solving this problem, we must remember that one mole of a compound contains Avogadro's number of elementary entities. These elementary entities include atoms, molecules, ions etc. Recall that one mole of a substance is the amount of substance that contains the same number of elementary entities as 12g of carbon-12. The Avogadro's number is 6.02 × 10^23.

Hence we can now say;

If 163 g of the compound contains 6.13 ×10^24 molecules

x g will contain 6.02 × 10^23 molecules

x= 163 × 6.02 × 10^23 / 6.13 × 10^24

x= 981.26 × 10^23/ 6.13 ×10^24

x= 160.1 × 10^-1 g

x= 16.01 g

x= 16 g(approximately)

16 g is the molecular mass of methane hence x must be methane (CH4)

Answer:

Partial pressure of hydrogen H₂ = 0.32 atm

Explanation:

Given:

Total pressure = 0.48 atm

Find:

Partial pressure of hydrogen

Computation:

Number of mole of H₂ = 1 / 2 = 0.5 moles

Number of mole of He  = 1 / 4 = 0.25 moles

Total moles = 0.5 + 0.25 = 0.75

Partial pressure of hydrogen H₂ = [moles / total moles] Total pressure

Partial pressure of hydrogen H₂ = [0.50 / 0.75]0.48 atm

Partial pressure of hydrogen H₂ = 0.32 atm

Answer: 0.32 atm

Explanation:

First convert the mass of H2 to moles using the molar mass.

(1.0 gram H2 ⋅ (1.0 mol H2 / 2.016 g H2)) ≈ 0.50 mol H2

Next, convert the mass of helium He to moles using the atomic mass.

(1.0 gram He ⋅ (1.0 mol He / 4.003 g He)) ≈ 0.25mol He

The total number of moles is about 0.75 moles . The partial pressure of a component of a gas mixture can be found by multiplying the mole fraction by the total pressure.

PH2 = XH2 × Ptotal

PH2 = (0.50 mol / 0.75 mol)(0.48 atm) = 0.32 atm

A nonmetal and a nonmetal will make molecular compounds like H2O and CO2

Answer:

Atomic radius of Strontium is 27.38pm

Explanation:

In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:

a² + a² = b² = (4r)²

2a² = 16r²

a = √8 r

As edge length of Strontium is 77.43pm:

77.43pm / √8 = r

27.38pm = r

Answer:

Light is composed of particles and travels in a straight line.

Explanation:

The general consensus among scientists in Sir Isaac Newton's time in the early 1700s was that light was composed of a steady stream of particles, since it was observed that light traveled in a straight line and was able to pass through a vacuum. They argued along the lines of Sir Isaac Newton that since sound travels in waves and cannot travel though a vacuum, light must consist of something other than waves, such as particles.

Also, on reflection of light from rough surfaces, the particle theory suggests that if the surface is very rough, the particles bounce away at different angles from the surface, scattering the light as is confirmed by experimental observation.

In his 1704 book Opticks, Sir Isaac Newton stated that "Light is never known to follow crooked passages nor to bend into the shadow". This idea lent support to the particle theory, which proposes that light particles must always travel in straight lines. If the particles encounter the edge of a barrier, then they will cast a shadow because the particles not blocked by the barrier continue on in a straight line and cannot spread out behind the edge. This was observed in eclipses as well as formation of shadow of objects.

Answer:

Light is composed of particles and travels in a straight line.

Explanation:

PF The majority of scientists in the early 1700s agreed that light must be particle-like, since it was apparent that light traveled in a straight line and was able to pass through a vacuum. Their logic was that since sound travels in waves and can't travel though a vacuum, light must consist of something other than waves, such as particles.

Answer:

Option B. 2096.1 K

Explanation:

Data obtained from the question include the following:

Enthalpy (H) = +1287 kJmol¯¹ = +1287000 Jmol¯¹

Entropy (S) = +614 JK¯¹mol¯¹

Temperature (T) =.?

Entropy is related to enthalphy and temperature by the following equation:

Change in entropy (ΔS) = change in enthalphy (ΔH) / Temperature (T)

ΔS = ΔH / T

With the above formula, we can obtain the temperature at which the reaction will be feasible as follow:

ΔS = ΔH / T

614 = 1287000/ T

Cross multiply

614 x T = 1287000

Divide both side by 614

T = 1287000/614

T = 2096.1 K

Therefore, the temperature at which the reaction will be feasible is 2096.1 K

Answer:

A) CH3CH2SH

Explanation:

Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a  non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.

Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.

Now; for option (A)

CH3CH2SH

The molar mass is :

= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)

= (12 + 3+ 12 + 2 + 32 + 1)

= 62 g/mol

For option (B)

CH3NH2

The molar mass is:

= (12 + (1 ×  3 ) +14 + (1 ×  2)

= (12 + 3 + 14 + 2)

= 31 g/mol

For option (C)

CH4

The molar mass is :

= 12 + (1 × 4)

= 12 + 4

= 16 g/mol

For option (D)

CH3CH3

The molar mass is :

= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)

= 12 + 3 + 12 + 3

= 30 g/mol

Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH

Answer:

THE HEAT CAPACITY OF THE CALORIMETER IS 3666.67 J/C

Explanation:

Mass = 2 g

Temperature difference = 32 C - 29 C = 3 C

Heat of combustion = 11 kJ/g

Heat capacity of the calorimeter = unknown

It is important to note that the heat of combustion of the reaction is the heat absorbed by the calorimeter in raising the mixture by 3 C

So therefore,

Heat = heat capacity * temperature difference

Heat capacity = Heat / temperature difference

Heat capacoty = 11 000 J / 3 C

Heat capacity = 3666.67 J/ C

Answer:

[tex]m_{CO_2}=46.6gCO_2[/tex]

Explanation:

Hello,

In this case, considering the combustion of propane:

[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)\ \ \ \Delta _CH=-2220.0 kJ/mol[/tex]

We can compute the burnt moles of propane as shown below:

[tex]n=\frac{-784kJ}{-2220.0 kJ/mol} =0.353molC_3H_8[/tex]

Then, by noticing propane and carbon dioxide are in a 1:3 molar ratio, we can compute the grams carbon dioxide by using the shown below stoichiometric procedure:

[tex]m_{CO_2}=0.353molC_3H_8*\frac{3molCO_2}{1molC_3H_8} *\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=46.6gCO_2[/tex]

Best regards.

Answer:

2.17x10⁻¹⁰ = Kb1

1.69x10⁻¹³ = Kb2

Explanation:

Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:

C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²

C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵

Oxalate ion, C₂O₄²⁻, has as equilibriums:

C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2

Also, you can know: KaₓKb = Kw

Where Kw is 1x10⁻¹⁴

Thus:

Kw = Kb2ₓKa1

1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵

And:

Kw = Kb1ₓKa2

1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²

That is because the inverse reaction of, for example, Ka1:

C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1

+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴

=

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1

Answer:

It may be a hemorrhagic stroke because of the patient's history.

Explanation:

Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain

The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state

Answer:

The total photons required = 5.19 × 10²⁸ photons

Explanation:

Given that:

the radiation wavelength λ= 12.5 cm = 0.125 m

Volume of the container = 0.250 L = 250 mL

The density of water = 1 g/mL

Density = mass /volume

Mass =  Volume ×  Density

Thus; the mass of the water =  250 mL ×  1 g/mL

the mass of the water = 250 g

the specific heat of water s = 4.18 J/g° C

the initial temperature [tex]T_1[/tex] = 20.0° C

the final temperature [tex]T_2[/tex] = 99° C

Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C

The heat q absorbed during the process = ms [tex]\Delta T[/tex]

The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C

The heat q absorbed during the process = 82555 J

The energy of a photon can be represented by the equation :

= hc/λ

where;

h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]

c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]

=  [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]

= [tex]1.59024 \times 10^{-24}[/tex] J

The total photons required = Total heat energy/ Energy of a photon

The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]

The total photons required = 5.19 × 10²⁸ photons

Answer:

second carbon atom from the  end

end carbon atom

Explanation:

Carbohydrates are naturally occurring organic compounds containing carbon, hydrogen and oxygen. The general molecular formula of Carbohydrates is [tex]C_x(H_2O)_y[/tex].

Carbohydrates can be classified based on structures,

Carbohydrates with the structure of alkanals (-CHO) are known as aldose while those of the structure of alkanones (C=O) are known as ketose.

In stereochemistry , D series is a kind of configurational arrangement where the hydroxyl group attaches itself to the right hand side.

Thus; in naturally occurring D series of ketoses, the carbonyl group is found on carbon number second carbon atom from the  end whereas in aldoses, the carbonyl group is found on carbon number end carbon atom.

A) The specific humidity of the air with the given parameters is;

w1 = 0.00967

B) The relative humidity of the air with the given parameters is;

Φ1 = 0.459

C) The enthalpy of the air in KJ/kg dry air with the given parameters is;

h1 = 49.75 KJ/Kg

Correct question is;

The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.

We are given;

Atmospheric Pressure;P = 95 KPa

Dry temperature;T1 = 25 °C

Wet temperature;T2 = 17°C

A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa

First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;

w2 = (0.622 × P_g2)/(P - P_g2)

w2 = (0.622 × 1.938)/(95 - 1.938)

w2 = 0.013

Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;

h_fg2 = 2460 KJ/Kg

h_g1 = 2546.5 KJ/Kg

h_f2 = 71.36 KJ/Kg

The formula for the specific humidity under these conditions is;

w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)

c_p of air has a value of 1.005 KJ/Kg.°C

Thus;

w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)

w1 = 0.00967

B) The relative humidity is determined from the equation;

Φ1 = (w1*p)/(0.622 + w1)p_g1

From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa

Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698

Φ1 = 0.459

C) For the enthalpy of air, h1 we will use the formula;

h1 = (c_p × T1) + (w1 × h_g1)

h1 = (1.005 × 25) + (0.00967 × 2546.5)

h1 = 49.75 KJ/Kg

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Answer:

3.01 × 10²³ molecules

Explanation:

Step 1: Given data

Moles of water (n): 0.500 mol

Step 2: Calculate the molecules of water present in 0.500 moles of water

In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.

0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules

Answer:

The correct answer is 17.845 hours.

Explanation:

To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.  

Based on Faraday's law, m = Mit/nF

Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).  

From the above mentioned equation,  

t = mnF/Mi ------(i)

Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.  

So, from the above gas law's equation, m = PVM/RT

Now putting the values of m in the equation (i) we get,  

t = PVMnF/MiRT = PVnF/iRT

Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.  

1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.  

Now putting the values we get,  

t = PVnF/iRT

= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K

= 64243.81 secs or 64243.81/3600 hr  

= 17.845 hours

Answer:

THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.

Explanation:

First:

Calculate the change in freezing point:

          Freezing point of pure benzene = 5.5°C

Change in temperature = 5.5 - 3.06 = 2.44 °C

Second:

Using the formula:

Δt = i Kf m

Let's assume i = 1

Kf = 5.12 °C/m

M = x / 0.250 kg of benzene

Then we can calculate x which is the molarity

Re-arranging the formula, we have:

m = Δt / i Kf

x / 0.250 = 2.44 / 1 * 5.12

x = 2.44 * 0.250 / 5.12

x = 0.61 / 5.12

x = 0.119 M

Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.

Molar mass = Mass / molarity

Molar mass = 28.8 g / 0.119 M

Molar mass =242.02 g/mol

Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.