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Rasek [7]
3 years ago
15

What are the signs that a chemical reaction has occurred

Chemistry
2 answers:
Finger [1]3 years ago
8 0
Well. There is the color change and the formation of bubbles. 
MrRa [10]3 years ago
8 0
Color change, formation of a precipitate, heat, formation of a gas, and odor
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The rate law for a hypothetical reaction is rate = k [A][B]. If the concentrations of A and B are both 0.020 moles per liter and
JulijaS [17]
The answer is c. 5.2 * 10^-5 Ms-1. The rate law for this reaction is given. So you only need to replace the letter with number given. And also calculate the unit. Then you can get answer.
5 0
3 years ago
If any 1 studying 11th can u plz send me the chemistry notes for chapter 2 STRUCTURE OF AN ATOM lesson
timofeeve [1]

Answer:

Atom is the smallest particle of matter that can take part in a chemical reaction.

Atom is made of electron, proton and neutrons.

Atom is not capable of independent existence.

Two or more atoms combine together to form molecules.

Electron:

Negatively charged particle discovered on the basis of ‘cathode ray discharge tube’ experiments.

Conclusion from ‘cathode ray discharge tube’ experiment:

Cathode rays start from cathode and move toward anode.

These rays are not visible but their behaviour can be observed with fluorescent or phosphorus sent material.

In the absence of electric or magnetic field these travels in strait lines.

In the presence of electric or magnetic field the behaviour of cathode rays is similar to negatively charged particles which suggest that these rays contain negatively charge particles called electron.

Proton:

Positively charged particle discovered on the basis of anode ray experiment.

Some of the characteristics of anode rays, also called canal rays, are:

These travel in straight line and posses mass many times the mass of an electron.

These are not originated from anode.

These are deflected by electric and magnetic field.

Unlike cathode rays, the positively charged particles depend upon the nature of the gas from which these originate.

Neutron:

Neutral particles discovered by bombarding a thin sheet of beryllium by α- particles.

Conclusion from α- particles scattering experiment:

Most of the α-particles passed through foil undeflected, indicating most of the space in atom is empty.

Some of the α-particles are deflected to certain angles, which means that there is positively mass present in atom.

Only some of the α-particles suffered large deflections, which means that the positively charged mass must be occupying very small space.

Strong deflections or even bouncing back of α-particles from metal foil indicate the direct collision with positively charged mass in atom.

Comparison between the subatomic particles of an atom

subatomic particles comparison

Thomson model of atom:

atom is considered asa uniform positively charged sphere with radius about 10-10 m, in which electrons are is uniformly distributed.

Electrons are embedded in such a manner to give most stable electrostatic arrangement.

Mass of atom is assumed to be uniformly distributed in atom.

Also known as plum pudding raisin pudding orwatermelon model.

Rutherford’s Nuclear Model of Atom:

Based upon α-particles scattering experiment.

Most part of the atom is empty.

Atom possesses a highly dense, positively charged centre, called nucleus of the order 10-13 cm.

Entire mass of the atom is concentrated inside the nucleus.

Electrons revolve around the nucleus in circular orbits.

Electrons and the nucleus are held together by electrostatic forces of attraction.

Drawbacks of Rutherford’s Model:

It doesn’t explain the stability of atom.

It doesn’t say anything about the electronic distribution of electrons around nucleus.

3 0
3 years ago
Read 2 more answers
N2 molecules absorb ultraviolet light but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of th
Umnica [9.8K]

C. Visible light does not produce transitions between electronic energy levels in the N₂ molecule but does produce transitions in the I₂ molecule.

Explanation:

Abortion of light by molecules will produce electronic transitions from a ground level to a higher level equal to the energy of absorbed light.

In the case of nitrogen (N₂) the allowed electronic transitions are between electronic energy levels with a energy difference equal to the energy of photons of the ultraviolet light. Nitrogen will not absorb from the visible range so it is colorless.

Now iodine (I₂) have the allowed electronic transitions between electronic energy levels with a energy difference equal to the energy of photons of the visible light. As a consequence Iodine vapors have a violet color.

Learn more about:

electronic transitions

brainly.com/question/11328705

#learnwithBrainly

4 0
3 years ago
When the pressure that a gas exerts on a sealed container changes from 22.5 psi to psi the temperature changes from 110 c to 65.
ad-work [718]
Gay- Lussacs law states that the pressure of a gas is directly proportional to temperature for a fixed amount of gas at constant volume.
therefore P/T = k
where P - pressure , T - temperature and k - constant 
\frac{P1}{T1} =  \frac{P2}{T2}

parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation 
T1 - temperature in kelvin - 110 °C + 273 = 383 K
T2 - 65.0 °C + 273 = 338 K
substituting these values in the equation 

\frac{22.5 psi}{383 K} =  \frac{P}{338K}
P = 19.9 psi 
new pressure is 19.9 psi
3 0
3 years ago
Explain the scientific meaning and use of the word "transformation".
sladkih [1.3K]

Transformation in chemistry is scientifically used to explain the process of changing one compound to another in a chemical reaction.

<h3>What is transformation?</h3>

The word "transformation" has a very special significance in chemistry. We know that in English, to transform would simply imply to change from one form to another. This is not quite far from its meaning in the parlance of chemistry.

The word transformation is normally applied in the area of chemical reactions especially as it has to do with reaction with in organic chemistry. It has to do with the change from one molecule to another and this is of great importance in the discussion of synthetic chemistry.

As such, the word transformation in chemistry is scientifically used to explain the process of changing one compound to another in a chemical reaction.

Learn more about chemical transformation:brainly.com/question/8210521

#SPJ1

8 0
2 years ago
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