Scientists in 1.legal services 2.research and development 3.marketing 4.corporate management

What are all 4 levels of the energy pyramid? HELP ASAP

NISA [10]

Producer, Primary consumers, Secondary consumers and Tertiary consumers.

7 0

3 years ago

The reaction described by H2(g)+I2(g)⟶2HI(g) has an experimentally determined rate law of rate=k[H2][I2] Some proposed mechanism

MatroZZZ [7]

Answer:

Mechanism A and B are consistent with observed rate law

Mechanism A is consistent with the observation of J. H. Sullivan

Explanation:

In a mechanism of a reaction, the rate is determinated by the slow step of the mechanism.

In the proposed mechanisms:

Mechanism A

(1) H2(g)+I2(g)→2HI(g)(one-step reaction)

Mechanism B

(1) I2(g)⇄2I(g)(fast, equilibrium)

(2) H2(g)+2I(g)→2HI(g) (slow)

Mechanism C

(1) I2(g) ⇄ 2I(g)(fast, equilibrium)

(2) I(g)+H2(g) ⇄ HI(g)+H(g) (slow)

(3) H(g)+I(g)→HI(g) (fast)

The rate laws are:

A: rate = k₁ [H2] [I2]

B: rate = k₂ [H2] [I]²

As:

K-1 [I]² = K1 [I2]:

rate = k' [H2] [I2]

Where K' = K1 * K2

C: rate = k₁ [H2] [I]

As:

K-1 [I]² = K1 [I2]:

rate = k' [H2] [I2]^1/2

Thus, just mechanism A and B are consistent with observed rate law

In the equilibrium of B, you can see the I-I bond is broken in a fast equilibrium (That means the rupture of the bond is not a determinating step in the reaction), but in mechanism A, the fast rupture of I-I bond could increase in a big way the rate of the reaction. Thus, just mechanism A is consistent with the observation of J. H. Sullivan

5 0

3 years ago

Which statement justifies that hydrogen peroxide (H2O2) is a polar molecule?

Rudik [331]

To determine whether a compound is polar or nonpolar you have to take into account:

1) formation of dipoles due to the difference in electronegativities of the atoms

2) shape of the molecule to conclude whether there is a net dipole momentum.

You already, likely, know that the electronegativities of H and O are significatively different, being O more electronegative thatn H. So, you can conclude easilty that the electrons are atracted more by O than by H, thus creating two dipoles H→O

Regarding the shape, it may appear that the molecule is symmetrical, which would lead to the cancellation of the two dipoles. But that is not the true. The H2O2 is not symmetrical.

The lewis structure just show this shape

** **
H - O - O - H
** **

which is what may induce to think that the molecule is symmetrical, leading to the misconception that it is nonpolar.

But in a three dimensional arrangement you could see that the hydrogens are placed in non symmetrical positions, which leads to the formation of a net dipole momentum, and thus to a polar molecule.

The fact that H2O2 is a polar compound is the reason why it can be mixed with water and the H2O2 that you buy in the pharmacy is normally a solution in water.

So, the hydrogen peroxide is polar because the hydrogens are not placed symmetrically in the molecule, which result in a net dipole momentum.

4 0

3 years ago

Your friend challenged you to a race you know in order to beat him you must run 15 meters within 20 seconds in the northern dire

Marat540 [252]

Answer:

.75 meter north

Explanation:

v = d/t

v = 15/20

v = .75

7 0

3 years ago

How to calculate delta S surroundings? calculate Delta S(surr) at the indicated temperature for a reaction having each of the fo

astraxan [27]

You can use the equation ΔS(surr)=q(surr)/T or ΔS(surr)=-q(rxn)/T.
the two equations are equal since we know that the energy the system (reactoin) puts out just goes into the surroundings.
(In other words q(surr)=-q(rxn))

Using the equation, ΔS(surr)=-(-283kJ/298K)=0.9497kJ/K or 949.7J/K

This answer makes sense since the reaction is exothermic which means it released energy into the system which usually causes the entropy to increase.

I hope that helps.

8 0

4 years ago