The expression for 11 million km in scientific notation is

(02.03 MC)

Olegator [25]

3 because of the thing it’s trying to say

7 0

3 years ago

Which statement best describes the relationship between photosynthesis and cellular respiration?

Elena L [17]

Answer:

Photosynthesis removes carbon from the atmosphere, and cellular respiration releases carbon back into the atmosphere.

Explanation:

The first option clearly expresses the relationship between photosynthesis and cellular respiration.

Cellular respiration releases carbon back into the atmosphere whereas photosynthesis removes the carbon from the atmosphere.

Photosynthesis is the process whereby green plants manufacture their food using carbon dioxide and water.

In cellular respiration, the product of the photosynthesis is used by organisms to produce energy.

5 0

3 years ago

A reaction is second order respect to the reactant A. If the reaction is 85% complete in 12 minutes, how long would it take for

AnnZ [28]

Answer:

e. 22s

Explanation:

Initial Concentration = 100

Final concentration = 15 ( Since the reaction is 85% complete)

Time = 12 minutes = 720 seconds

The integrated rate law for second order reactions is given as;

1 / [A] = (1 / [A]o) + kt

Making k subject of interest, we have;

kt = (1 / [A] ) - (1 / [A]o )

k = (1 / [A] ) - (1 / [A]o ) / t

k = [(1/ 15) - (1 / 100) ] / 720

k = (0.0667 - 0.01 ) / 720

k = 0.0567 / 720

k = 7.875e^-5

How long would it take for the reaction to be 15% complete?

Final concentration = 85 (Since the reaction would be 15% complete)

The integrated rate law for second order reactions is given as;

1 / [A] = (1 / [A]o) + kt

Making t subject of interest, we have;

kt = (1 / [A] ) - (1 / [A]o )

t = (1 / [A] ) - (1 / [A]o ) / k

t = [(1 / 85 ) - (1 / 100) ] / 7.875e^-5

t = (0.0117 - 0.01 ) / 7.875e^-5

t = 0.001765 / 7.875e^-5

t = 22.41 seconds

Corect option = E.

3 0

4 years ago

In this chemical Formula for Ammonia, the Subscripts indicate what?

zubka84 [21]

Answer:

B

Explanation:

B. There are two atoms of Nitrogen and two atoms of Hydrogen combined to make Ammonia.

7 0

3 years ago

A sample of gas occupies a volume of 61.5 mL . As it expands, it does 130.1 J of work on its surroundings at a constant pressure

Lesechka [4]

Answer:

the final volume of the gas is $V_2$ = 1311.5 mL

Explanation:

Given that:

a sample gas has an initial volume of 61.5 mL

The workdone = 130.1 J

Pressure = 783 torr

The objective is to determine the final volume of the gas.

Since the process does 130.1 J of work on its surroundings at a constant pressure of 783 Torr. Then, the pressure is external.

Converting the external pressure to atm ; we have

External Pressure $P_{ext}$ :

$P_{ext} = 783 \ torr \times \dfrac{1 \ atm}{760 \ torr}$

$P_{ext} = 1.03 \ atm$

The workdone W = $P_{ext}$ V

The change in volume ΔV= $\dfrac{W}{P_{ext}}$

ΔV = $\dfrac{130.1 \ J \times \dfrac{1 \ L \ atm}{ 101.325 \ J} }{1.03 \ atm }$

ΔV = $\dfrac{1.28398717 }{1.03 }$

ΔV = 1.25 L

ΔV = 1250 mL

Recall that the initial volume = 61.5 mL

The change in volume V is $\Delta V = V_2 -V_1$

$- V_2= - \Delta V -V_1$

multiply through by (-), we have:

$V_2= \Delta V+V_1$

$V_2$ = 1250 mL + 61.5 mL

$V_2$ = 1311.5 mL

∴ the final volume of the gas is $V_2$ = 1311.5 mL

5 0

3 years ago