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3 years ago

Select all the correct answers,

Chemistry

1 answer:

Anastasy [175]3 years ago

7 0

Answer:

The reaction for which ΔH is positive are endothermic reactions.

Explanation:

The energy changes occur during the bonds formation and bonds breaking.

There ere two types of reaction endothermic and exothermic reaction.

Endothermic reactions:

The type of reactions in which energy is absorbed are called endothermic reactions.

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O → CO + H₂

ΔH = +131 kj/mol

it can be written as,

C + H₂O + 131 kj/mol → CO + H₂

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Passenger airplanes take off in the troposphere but can eventually move into

zhuklara [117]

Well that is because the stratosphere has lower temperatures and low air density. This gives the airplane less air pressure and with low air density they can fly faster :) Hope this helps.

5 0

3 years ago

A gas tank holds 20000 liters at 850 torr. If the temperature remains constant, what will the volume, in L, of the gas be at sta

nekit [7.7K]

Answer: 22368.4 Liters

Explanation:

Initial Volume of gas V1 = 20000 liters

Initial pressure of gas P1 = 850 torr

Final volume V2 = ?

Final (standard) pressure P2 = 760 torr

Apply the formula for Boyle's law:

P1V1 = P2V2

850torr x 20000L = 760torr x V2

V2 = (850torr x 20000L)/ 760torr

V2 = (17000000)/760torr

V2 = 22368.4L

Thus, the volume of the gas at standard pressure is 22368.4 Liters

6 0

4 years ago

In a fuel cell there is direct conversion of mechanical energy into electricity.

rewona [7]

Answer:

Explanation:

A fuel cell uses both hydrogen and oxygen as fuels. At the cathode oxygen is reduced to water according to the equation

O2+4H^+ +4e ------>2H2O

And hydrogen is oxidized at the anode:

2H2------>4H^+ +4e

Fuel cells produce only water as a by product hence they are environment friendly

5 0

3 years ago

4. Write down the differentiate between a. Atom and molecules

andre [41]

Answer:

Atoms are single neutral particles. Molecules are neutral particles made of two or more atoms bonded together.

Explanation:

Atom refers to the smallest constituent unit of a chemical element. Molecules refer to a group of two or more atoms that are held together due to chemical bonds.

7 0

3 years ago

Read 2 more answers

In another experiment, a 0.150 M BF4^-(aq) solution is prepared by dissolving NaBF4(s) in distilled water. The BF4^-(aq) ions in

Ilia_Sergeevich [38]

Answer:

A) Forward rate = 1.1934 × 10^(-4) M/min

B) I disagree with the claim

Explanation:

A) We are told that [HF] reaches a constant value of 0.0174 M at equilibrium.

The reversible reaction given to us is;

BF4-(aq) +H20(l) → BF3OH-(aq) + HF(aq)

From this, we can see that the stoichiometric ratio is 1:1:1:1

Thus, concentration of [BF4-] is now;

[BF4-] = 0.150 - 0.0174

[BF4-] = 0.1326 M

From the rate law, we are told the forward rate is kf [BF4-].

We are given Kf = 9.00 × 10^(-4) /min

Thus;

Forward rate = 9.00 × 10^(-4) /min × (0.1326M)

Forward rate = 1.1934 × 10^(-4) M/min

(B) The student claims that the initial rate of the reverse reaction is equal to zero can't be true because at equilibrium, rates for the forward and reverse reactions are usually equal.

Thus, I disagree with the claim.

3 0

3 years ago