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Alex787 [66]
3 years ago
7

Which processes represent one chemical change

Chemistry
2 answers:
brilliants [131]3 years ago
5 0
I believe the answer is (3) since decomposition is a chemical change and melting is a physical change
Sedaia [141]3 years ago
4 0

Answer: (3) decomposition and melting

Explanation: Chemical change is one in which chemical composition of substance changes.

Physical change is one in which chemical composition of substance do not change.

Freezing is a process in which a liquid changes into solid phase when allowed to cool. Thus it is a physical change.

Melting : It is process in which a solid changes into liquid phase by providing heat. Thus it is a physical change.

Vaporization : It is process in which liquid changes into gaseous phase by providing heat. Thus it is a physical change.

Decomposition is a chemical reaction in which one substance decomposes to form two or more than two products. Thus the chemical composition change, and hence is a chemical change.

Combustion is a reaction in which a substance combines with oxygen gas to produce carbon dioxide, water and a lot of heat. Thus the chemical composition change, and hence is a chemical change.

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Nuclear physicists have discovered over 100 different particles that compose the nucleus of an atom. From a chemistry perspectiv
Julli [10]

Answer:

Protons and neutrons which packed tightly into central core of the atom.

Explanation:

Atoms are composed of three subatomic particle; electron, proton and neutron. Electrons are negatively charged, protons are positively charged whereas neutrons are neutral, hence does not have any charge.

Out of three, protons and neutrons are present in the nucleus of the atom.

Nucleus is the central part of the atom possessing most of the mass of the atom. In the nucleus, protons and neutrons are tightly packed with the help of nuclear force.

Electrons are present around the nucleus also called electron cloud.

Therefore, nucleus are composed of protons and neutrons which packed tightly into central core of the atom

4 0
3 years ago
Ultra Clorox bleach is 6.68% sodium hypochlorite in water. How much of each is needed to make an 800.mL bottle?
sweet-ann [11.9K]
If we have 6.68% NaClO, it is the same as saying--> 6.68 grams NaClO= 100 mL of solution. we can use this as a conversion. 

800. mL (6.68 mL/ 100 mL)= 53.4 mL

solution = solute + solvent

solute= NaClO
solvent= H2O

solvent= 800-53.4= 747 mL of H2O

so, we you need 53.4 mL of NaClO and 747 mL of water or 53.4 grams of NaClO and 747 mL of water
7 0
3 years ago
Below are the steps of the engineering process (not necessarily in order): 1) Know the background 2) Do the work 3) Make a plan
LuckyWell [14K]

Answer:

4 - 1 - 3 - 2 - 6 - 5

Explanation:

During an engineering process, first, we need to identify the problem, or the need because the process only will occur because of some need. Then, it's necessary to know as much as possible about the problem and the things that already exist or already were tested to solve it. Knowing the background will make the work easy.

After that, it's necessary to plan the things we'll do, knowing the costs, the time needed for activities, how many people will be necessary for each step, etc. It's really important to make a plan. Then, do the work, following the plan. Thus, the process must be tested. During the test of the results, some problems must be found, so it's time to evaluate and redesign the process, to solve these problems found.

3 0
3 years ago
4.81*10^24 atoms of lithium
enyata [817]

Answer:

Mass = 55.52 g

Explanation:

Given data:

Number of atoms of Li = 4.81×10²⁴ atom

Number of grams = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For Li:

4.81×10²⁴ atom × 1 mol / 6.022 × 10²³ atom

8 moles

Mass in gram:

Mass = number of moles × molar mass

Mass = 8 mol × 6.94 g/mol

Mass = 55.52 g

4 0
3 years ago
Which type of allergy test, also called a subcutaneous test, introduces dilute solutions of allergens into the skin of the inner
alexgriva [62]

Answer:

The type of allergy test is scratch test.

Explanation:

In a scratch test also called a skin pri c k test or puncture test, an allergy provoking substance placed on the skin is gradually scratched  into the skin surface with the aid of a needle or lancet so as to detect bodily reactions to allergens. Some of the types allergens whose reactions are generally tested for include pollen, dust mites, molds and foods.

The scratch test takes about 5 to 10 minutes and it could cause slight pain and the may  result in itching feeling at the location where the allergen was introduced.

6 0
4 years ago
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