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hammer [34]
3 years ago
12

Give an example of each of the following chemical changes.

Chemistry
1 answer:
Andrews [41]3 years ago
7 0

Answer:

Give an example of each of the following chemical changes.

(a) A photochemical reaction involving

(i) silver salt

(ii) water

(b) A reaction involving

(i) blue solution

(ii) formation of dirty green precipitate

(c) Two gases combine to form white solid.

(d) A reaction where colour change is noticed.​

Explanation:

a) A photochemical reaction involving  silver salt is used in black and white photography.

AgCl breaks down and converts into Ag during this photochemical reaction.

(ii) Photochemicalreaction involving water takes place in plants during the photosynthesis process.

Plants prepare food(carbohydrate) by using sunlight water and CO2 gas.

(b) A reaction involving

(i) blue solution:

For example reaction of copper sulfate solution with an iron nail.

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

(ii) Reaction of ferrous sulfate with NaOH forms a dirty green precipitate of ferrous hydroxide.

(C) Two gases combine and form a white solid:

For example when HCl gas reacts with ammonia gas, then a white solid of ammonium chloride will be formed.

(d)  A reaction where the color change is noticed.:

When an iron nail is placed in CuSO4 blue color solution, then it changes to green color and reddish-brown solid deposits at the bottom of the container.

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BrO3- (aq) + NO2(aq) → Br-(aq) + NO3-(aq) Balance this reaction in acidic conditions?
Thepotemich [5.8K]

Answer:

BrO₃⁻ (aq) + NO₂(aq) + 4 H⁺→ Br⁻(aq) + NO₃⁻ + 2 H₂O

Explanation:

The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.

Then, you must balance the chemical equation. For that, you must first look at the subscripts next to each atom to find the number of atoms in the equation. If the same atom appears in more than one molecule, you must add its amounts.  

The coefficients located in front of each molecule indicate the amount of each molecule for the reaction. This coefficient can be modified to balance the equation, just as you should never alter the subscripts.

By multiplying the coefficient mentioned by the subscript, you get the amount of each element present in the reaction.

Then, taking into account all of the above, you can determine the amount of elements on each side of the equation:

Left side: 1 Br, 5 O and 1 N

Right side: 1 Br, 3 O and 1 N

If the reaction occurs in an acidic medium:

  • Each excess oxygen atom is balanced by adding a molecule of water to the other side of the reaction.
  • Hydrogens are balanced by adding protons (H⁺) on the opposite side to the water molecules.

So, balancing the oxygen:

BrO₃⁻ (aq) + NO₂(aq) → Br⁻(aq) + NO₃⁻ + 2 H₂O

Left side: 1 Br, 5 O and 1 N

Right side: 1 Br, 5 O, 1 N and 4 H

Then, balancing the hydrogens:

<em><u>BrO₃⁻ (aq) + NO₂(aq) + 4 H⁺→ Br⁻(aq) + NO₃⁻ + 2 H₂O</u></em>

Left side: 1 Br, 5 O, 1 N and 4 H

Right side: 1 Br, 5 O, 1 N and 4 H

You can see that you have the same amount on each side of the reaction. So the reaction is balanced.

6 0
3 years ago
In a short paragraph, describe how I fuel cell works.
nirvana33 [79]

Explanation:

passing hydrogen through the anode of a fuel cell and oxygen through the cathode.

hopes this helps

7 0
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What type of change is this picture showing?
sladkih [1.3K]

Answer: physical

Explanation: freezing and melting are physical changes.

8 0
3 years ago
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bogdanovich [222]

Answer:

1. Rutherford did the scattering experiment and observed that some of the rays bounce back. He concluded that there is a mass in which positive charge is concentrated. This marks the discovery of nucleus.

2. J.J Thomson discovered electrons by conducting cathode ray experiment.

3. Dalton postulated that matter is made up of small particles caled atoms

8 0
3 years ago
Choose a likely identity for X, Y, and Z in these structures. A central X atom is bonded to two chlorine atoms through single bo
11111nata11111 [884]

Answer:

X= Be

Y= B

Z=O

Explanation:

From the description of the compound XCl2, among the options listed only beryllium can form such compound with three lone pairs in the two chlorine atoms and no lone pair on the central atom X.

From the description of YCl3, only Boron among the options listed can form such a compound with no lone pair on the central atom and three lone pairs on each of the chlorine atoms.

From the description of ZCl2, only oxygen forms the compound OCl2 among the elements listed where oxygen possesses two lone pairs and each chlorine atom possesses three lone pairs each.

8 0
3 years ago
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