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3 years ago

What happens to the motion of molecules in a substance is cooled?

1 answer:

7 0

The motion becomes smaller. Lets tale the example of water. At gaseous state, the particles moves rapidly in all directions. As it is cooled, it becomes liquid and the motion becomes smaller because the particles are now closer to each other as the attraction forces becomes stronger. As it is cooled further, it becomes solid. At solid state, the particles now vibrate in fixed position. Apply this concept to motion of molecules in a substance.

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A machine have 75% efficiency,what does it mean.

Kazeer [188]

Answer:

A machine have 75% efficiency means 25% of efficiency has been lost due to friction and a machine can work 75% only.

8 0

3 years ago

In the reaction of sodium and oxygen, which atom is the reducing agent?

pishuonlain [190]

Sodium is the reducing agent because a reducing agent is always the donor of electrons.

8 0

3 years ago

Consider this equilibrium reaction between carbon monoxide and hydrogen gas, occurring in a sealed flexible container. CO(g) + 3

wariber [46]

Answer:

More H2(g) is added to the container : Towards products.

CO is removed from the container : Towards reactants.

More CH4(g) is added to the container : Towards reactants

H2O(g) is removed from the container : Towards products.

The contents of the container are heated up. : Towards the reactants.

The contents of the container are cooled down : Towards the products.

The pressure inside the container is increased. :Towards the products

The container is stretched to increase the volume: Towards the reactants.

Explanation: :

CO(g) + 3 H2g) → CH4(g) + H2O(g)+ heat

There is released heat, so this reaction is exothermic

If the H2 concentration is increased, the system will try to change the concentration change by shifting the balance to the right, and thus the concentration of products will increase. Towards products.

If the CO is removed, the system will try to change this situation by shifting the balance to the left, and thus the concentration of reactants will increase, the concentration of products will decrease. Towards reactants.

If the CH4 concentration is increased, the system will try to change the concentration change by shifting the balance to the left, and thus the concentration of reactants will increase. Towards reactants

If the H2O is removed, the system will try to change this situation by shifting the balance to the right, and thus the concentration of products will increase, the concentration of products will decrease. Towards products.

If the temperature is increased, the system will reduce the amount of heat released. So the balance will shift to the left. Towards the reactants.

This because the extra heat / energy must be used.

If the temperature is decreased, the system will produce more heat So the balance will shift to the right. Towards the products.

This because more heat /energy needs to be produced to make up for the loss of heat (energy).

If the pressure is increased, the system will shift to the side with fewer moles of gas. In this case, there are 4 moles on the left and 2 moles on the right. So the balance will shift to the right. Towards the products. An increase of pressure has the same effect on the equilibrium as a decrease of the volume.

If the volume is increased, this means the pressure is decreased, the system will shift to the side with most moles of gas. In this case, there are 4 moles on the left and 2 moles on the right. So the balance will shift to the left. Towards the reactants. An increase of volume has the same effect on the equilibrium as a decrease of the pressure.

6 0

3 years ago

Apart from plants, what other group of organisms photosynthesises?

Licemer1 [7]

Answer:

Plants, algae, and a group of bacteria called cyanobacteria are the only organisms capable of performing photosynthesis

4 0

2 years ago

Why doesn’t the KHP concentration have to be exactly 0.100M? Explain using complete sentences.

ollegr [7]

Answer:

The answer is in the explanation.

Explanation:

The KHP is an acid used as standard in titrations to find concentration of bases as NaOH.

The reaction that explain this use is:

KHP + NaOH → KNaP + H2O

where 1 mole of KHP reacts per mole of NaOH

That means, at equivalence point of a titration in which titrant is NaOH, the moles of KHP = Moles of NaOH added

With the moles of KHP = Moles of NaOH and the volume used by titrant we can find the molar concentration of NaOH.

The moles of KHP are obtained from the volume and the concentration as follows:

Volume(L)*Concentration (Molarity,M) = moles of KHP

If the concentration is more or less than 0.100M, the moles will be higher or lower. For that reason, we need to know the concentration of KHP but is not necessary to be 0.100M.

8 0

3 years ago