CHEMISTRY MIDDLE SCHOOL

When an electric kettle containing cold water is switched on, the water in it starts boiling after a few minutes. What is the source of the heat energy of the boiling water? (3 points)a. Mechanical energy from the power socket

b. Newly created energy that increased the total energy

c. Mechanical energy from the heating element in the kettle

d. Already existing energy that was present in some other form

Answers

Answer 1

Answer:

Answer:

c. Mechanical energy from the heating element in the kettle

Answer 2

Answer: C is correct
Hope you do good

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What type of Technology would you want to use to study the gas giant planets

Answers

To study the gas giants, scientists and space explorers used spacecraft and probes. And also, one of the breakthroughs, that made exploration in the outer planet much easier was the planet gravity assist concept wherein, a much smaller space craft is used to launch in order to cope up with the accelerated speed if a spacecraft approaches the planet.

.An alkane reacts with a halogen to form a halocarbon. What is the role of UV light in this reaction?

It provides energy for the reaction.

It is released by the reaction.

It catalyzes the reaction.

PLEASE EXPLAIN YOUR ANSWER

Answers

Answer:

First choice: it provides energy for the reaction.

Explanation:

Alkanes are relative stable molecules: saturated chains of carbon and hydrogen atoms, where each carbon atom is hydridized sp³ and is bonded to one or two carbon atoms and 2 or 3 hydrogen atoms.

The C-H bonds are slightly polar (carbon is more electronegative than oxygen).

On the other hand, the diatomic halogen molecule (F₂, Cl₂, Br₂, or I₂) is a non-polar molecule.

The mechanism of reaction between the alkane and the halogen is via free radicals: the halogen molecule must be splitted into two radicals (two atoms each with a free electron). This implies the rupture of the diatomic halogen, and this requires an important amount of energy. The role of the UV ligth is to provide the energy to split the halogen molecule and, in this way, start the reaction.

Then, the free halogen radical may react with the alkane molecule breaking a C - H bond and substituting the leaving hydrogen atom, forming a C - X bond (X represents the halogen atom).

As a demonstration of this role, you may find in the specialized textbooks this typical reaction:

CH₄ + Cl₂ + energy → CH₃Cl + HCl

The energy shown in the reactant side may be supplied as UV light or heat. So, the role of UV light is to provide energy to start the reaction.

Answer:

It provides energy for the reaction.

Explanation: gradpoint

What are small round structures in the cell that breaks down large food particles into smaller ones

Answers

Lysosomes break down large food particles into smaller ones in a cell.

the small particles are known as protiens

where earths plates move , they may slide alongside one another , pull apart , or ? is the answer A . collide or B . divide ?

Answers

A is the answer. From the packet.

The hottest layer of the atmosphere

Answers

That would be the thermosphere, just above the mesosphere, and right below the exosphere.

write the equation for the combined gas law using temperature in degree Celsius. explain why the Kelvin scale is convenient

Answers

Answer:

$(PV)/(T)=k$

Explanation:

Combine Gas law is a combination of three gas laws which are Boyle's Law, Charles' Law, and Gay-Lussac's Law.

Combine gas law states that the ratio of the product of pressure and volume and the absolute temperature of a gas is equal to a constant.

Hence the equation becomes:

$(PV)/(T)=k$

where P = pressure,

V = volume,

T = absolute temperature,

k = constant.

Now we know that Kelvin = °Celsius + 273

For all gas law problems it is necessary to work in the Kelvin scale because temperature is in the denominator in the combined gas laws (P/T, V/T and PV/T) and can be derived in the ideal gas law to the denominator (PV/RT) . If we measured temperature in Celsius we could have a value of zero degrees Celsius and this would solve as no solution, as you cannot have zero in the denominator.

However, if we reached zero in the Kelvin scale this would be absolute zero and all matter would stop and therefore there would be no gas laws to worry about.

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