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3 years ago

Light elements with an atomic number less than 20 generally have a neutron to proton ratio equal to

1 answer:

6 0

Atomic elements consist of a nucleus that contains protons and neutrons. Protons carry a positive charge whilst neutrons are electrically neutral. In light elements with an atomic number less than 20, the neutron to proton ratio is generally equal to 1:1. This changes for heavier elements since the Coulomb interaction between many protons gets stronger and demands more neutrons for the nucleus to remain stable.

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Watching the assignment without knowing how to solve the questions is the worst thing to experience hope someone can help with t

frez [133]

Answer:

- 622.5kJ

Explanation:

1) 2NH3 + 3N2O ----> 4N2 + 3H2O ΔH° 1= - 1010kJ

- 3 (N2O + 3H2 ---> N2H4 + H2O ΔH° 2 = - 317 kJ)

2) 2NH3 + 3N2O ----> 4N2 + 3H2O ΔH° 1= - 1010kJ

- 3N2O - 9 H2 ----> - 3N2H4 - 3H2O - 3ΔH° 2 = 3*317 kJ

2NH3 + 3N2H4 --->4N2+9H2, ΔH° 1 - 3*ΔH° 2

2NH3 + 3N2H4 --->4N2+9H2, ΔH° 1 - 3*ΔH° 2

3) -(2NH3 +1/2O2 ---> N2H4 + H2O, ΔH°3 = -143 kJ)

-2NH3 - 1/2O2 ---> - N2H4 - H2O, - ΔH°3 = 143 kJ

2NH3 + 3N2H4 --->4N2+9H2, ΔH° 1 - 3*ΔH° 2

-2NH3 - 1/2O2 ---> - N2H4 - H2O, - ΔH°3 = 143 kJ

4N2H4 + H2O ---> 4N2 + 9H2 + 1/2O2, ΔH° 1 - 3*ΔH° 2 - ΔH°3

H2 + 1/2O2 ---> H2O, ΔH° 4 = - 286 kJ

9*(H2 + 1/2O2 ---> H2O, ΔH° 4 = - 286 kJ)

9H2+ 9/2 O2 ---> 9H2O, 9*ΔH° 4 = 9*(- 286) kJ

4N2H4 + H2O ---> 4N2 + 9H2 + 1/2O2, ΔH° 1 - 3*ΔH° 2 - ΔH°3

9H2+ 9/2 O2 ---> 9H2O, 9*ΔH° 4 = 9*(- 286) kJ

4N2H4 +4O2 --->4N2+8H2O, ΔH° 1 - 3*ΔH° 2 - ΔH°3 + 9*ΔH° 4

1/4*(4N2H4 +4O2 --->4N2+8H2O, ΔH° 1 - 3*ΔH° 2 - ΔH°3 + 9*ΔH° 4

N2H4 +O2 --->N2+2H2O, 1/4( ΔH° 1 - 3*ΔH° 2 - ΔH°3 + 9*ΔH° 4)

N2H4 +O2 --->N2+2,

1/4( ΔH° 1 - 3*ΔH° 2 - ΔH°3 + 9*ΔH° 4)=

=1/4(-1010kJ - 3*(-317kJ) - (-143kJ) + 9*(-286kJ))= - 622.5 kJ

7 0

3 years ago

Which of the following is a structure of a cow?

AfilCa [17]

Answer:

None of the above.

Explanation:

None of thesse things are part of the structure of a cow, cows have dished forhead 4 stomachs and angular body not sharp teeth comin when called or hooved feet.

6 0

3 years ago

3. A volume of 90 mL of 0.2 M HBr neutralizes

svlad2 [7]

Answer:

0.3M

Explanation:

Step 1:

Data obtained from the question. This include the followingb:

Volume of acid (Va) = 90mL

Concentration of acid (Ca) = 0.2M

Volume of base (Vb) = 60mL

Concentration of base (Cb) =....?

Step 2:

The balanced equation for the reaction. This is given below:

HBr + NaOH —> NaBr + H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 1

The mole ratio of the base (nB) = 1

Step 3:

Determination of the concentration of the base, NaOH.

The concentration of the base can be obtained as follow:

CaVa /CbVb = nA/nB

0.2 x 90 / Cb x 60 = 1

Cross multiply

Cb x 60 = 0.2 x 90

Divide both side by 60

Cb = 0.2 x 90 /60

Cb = 0.3M

Therefore, the concentration of the base, NaOH is 0.3M

7 0

3 years ago

Read 2 more answers

Revise and repeat: Is more water always better? Create your own experiments to find the ideal amount of water for each kind of p

sergij07 [2.7K]

More water is not always better. For example; cacti only need water about every two weeks, the same with succulent plants. Not every plant needs to be watered every day, or the plant may be overwatered and die.

7 0

3 years ago

Consider the following reaction at equilibrium. What will happen if SO2SO2 is added to the reaction? 4FeS2FeS2(s) + 11O2O2(g) ⇌⇌

kupik [55]

Answer:

The equilibrium will change in the direction of the reactants

Explanation:

7 0

3 years ago