Which of the following chemical compounds contains two hydrogen atoms in every molecule?

How would this change affect the food web?check all that apply

klio [65]

During the summer, when the land is brown and the grass is green, the population of mice decreases because mice are easily spotted by the organisms that eat them.

How would this change affect the food web? Check all that apply.

A. It will increase the grass population.

D. It will decrease the snake population

E. It will increase the grasshopper population

hope this helps! If so please mark brainliest and rate/heart to help my account if it did!!

7 0

3 years ago

One mole of a monatomic ideal gas is subjected to the following sequence of steps: a. Starting at 300 K and 10 atm, the gas expa

Verdich [7]

Answer:

a) Q = 0; W = 0; ΔU = 0; ΔH = 0; ΔS = 0.09 atm.L/K

b) Q = 1250 J; W = 0; ΔU = 1250 J; ΔH = 1250 J; ΔS = -0.0235 atm.L/K

c) Q = 3653.545 J; W = - 3653.545 J; ΔU = 0; ΔH = 0; ΔS = - 3653.545 J

d) Q = - 2080 J; W = 830 J; ΔU = - 1250 J; ΔH = - 2080 J; ΔS = - 5.984 J/K

Explanation:

a) If there is a vacuum, the work is zero, as it is a free expansion, the volume increases, the pressure decreases, the temperature is constant and the internal energy is constant.

∴ n = 1 mole

∴ PV = RTn....ideal gas

∴ P1 = 10 atm

∴ R = 0.082 atm.L/K.mol

∴ T = 300 K = T2

∴ V2 = 3*V1

⇒ W = 0.....expands freely into vacuum

⇒ ΔU = Q = 0....first law

⇒ ΔS = - nR Ln(P2/P1).....ideal gas

∴ V1*P1/T1 = V2*P2/T2

∴ T1 = T2 = 300 K

⇒ P2 = V1*P1 / V2 = V1*P1 / 3V1 = 10 atm/3 = 3.33 atm

⇒ ΔS = - (1mol)*(0.082 atm.L/K.mol) Ln ( 3.33/10)

⇒ ΔS = 0.09 atm.L/K

∴ ΔH = ΔU + (P2V2 - P1V1) = 0 + 0 = 0

b) heated reversibly at constant volume:

⇒ W = 0 ...at constant volume

∴ T2 = 400 K; T1 = 300 K

∴ V1 = V2

⇒ Q = ΔU = CvΔT....first law

∴ Cv = 12.5 J/K.mol.....monoatomic ideal gas

∴ ΔT = 400 - 300 = 100 K

⇒ Q = ΔU = 12.5 J/mol.K * 100K = 1250 J/mol * 1 mol = 1250 J

∴ ΔH = ΔU + PΔV = ΔU + 0 = 1250 J

∴ ΔS = - nR Ln (P2/P1)

∴ P2/T2 = P1/T1...constant volume

∴ P1 = 3.33 atm

⇒ P2 = P1*T2 / T1 = (3.33 atm)*(400K) / (300K) = 4.44 atm

⇒ ΔS = - (1mol)*(0.082atm.L/K.mol) Ln (4.44/3.33)

⇒ ΔS = - 0.0235 atm.L/K

c) reversibly expanded at constant temperature:

∴ T1 = T2 = 400K

∴ V2 = 3*V1

∴ ΔU = 0...constant temperature

⇒ Q = - W....fisrt law

∴ W = - ∫ PdV..... reversibly expansion

∴ P = nRT/V... ideal gas

⇒ W = - nRT ∫ dV/V

⇒ W = - nRT Ln (V2/V1)

⇒ W = - (1mol)*(8.314 J/K.mol) Ln (3)

⇒ W = - 9.134 J/K *400K = - 3653.545 J

⇒ Q = - W = 3653.545 J

⇒ ΔH = ΔU + P1V1 - P2V2 = 0 + nRT1 - nRT2 = 0 + 0 = 0

∴ ΔS = - nR Ln(P2/P1)

∴ P1 = 4.44 atm

⇒ P2 = V1*P1*T2/ V2*T1 = V1*(4.44atm)*(400K) / (3.V1)*(400K)

⇒ P2 = 4.44atm/3 = 1.48 atm

⇒ ΔS = - (1mol)*(8.314 J/mol.K) Ln (1.48/4.44)

⇒ ΔS = -9.134J/K * 400K = - 3653.545 J

d) reversibly cooled at constant pressure:

∴ T2 = 300 K; T1 = 400 K

∴ P2 = P1

⇒ Q = ΔH = CpΔT

∴ Cp = 20.8 J/K.mol

∴ ΔT = 300 - 400 = - 100 K

⇒ Q = ΔH = 20.8 J/mol.K * ( -100K) = - 2080 J/mol * 1mol = - 2080 J

⇒ ΔU = nCvΔT = (1mol)*(12.5 J/mol.K)*( - 100K) = -1250 J

⇒ W = ΔU - Q = ΔU - ΔH = -1250 J - ( - 2080 J ) = 830 J

∴ ΔS = ∫ δQ/T = ∫ nCpdT/T

⇒ ΔS = nCp Ln (T2/T1)

⇒ ΔS = (1mol)*(20.8 J/mol.K) Ln (300/400) = - 5.984 J/K

7 0

3 years ago

How can objects all be the same size but have a different mass? *help quick*

Elodia [21]

Answer:

All objects can have the same size but have a different mass!

This is true, although it sounds fake. This is one example, there is a Neutron star, and Neutron stars are as big as a city, but they have a mass which is hundreds of times greater than our sun's mass. Because of them having so much mass, they are also having so much gravitational energy, which makes them also have gravity. They're so small, but have so much mass that they can do much. Even a drop of a neutron star can punch open the earth! It's true, so yes, it is possible for objects the SAME size to be having different masses according to that example.

But let's look on how they can have different mass.

They can have different masses becase of different densities. Put a iron ball inside water, and put an apple as close to the iron ball's side, what happens? The apple floats, becuase the apple's mass is less than the water, and the iron ball's mass is MORE than the water. So, because the iron ball is denser than the apple, that's why, it has more mass than the apple. The apple isn't much dense, it isn't as dense as water or the iron ball. But the iron ball is much more denser than the water. So because of the different material densities of the material, that's why it can have different masses.

Remember to Remember those 2 examples I gave you... (neutron star vs sun, iron ball vs apple on water)

8 0

2 years ago

Thirsty Thursday:) post your celebrity crush <br> Or post your favorite drink :)

Nata [24]

Answer:

My celebrity crush is young Keanu Reeves and my favorite drink is matcha tea

Explanation:

7 0

3 years ago

A tire at 21°C has a pressure of 0.82 atm. Its temperature decreases to –3.5°C. If there is no volume change in the tire, what i

Phantasy [73]

Using ideal gas equation, PV = nRT, and since there is no volume change and amount change, the equation is now P = kT, where k =nR/V. Temperature must be in kelvin From the given, k = (0.82)/ (21 + 273) = 2.78 x 10^-3 Substituting T = -3.5+273, P = 0.75 atm

7 0

3 years ago

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