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3 years ago

PLS ANSWER ALL QUESTIONS FOR 67 POINTS

Chemistry

1 answer:

Elena L [17]3 years ago

3 0

Explanation:

1. subatomic particles.

2.proton, electron and neutron

3.The atomic mass of an element is actually the sum of the MASSES of protons and neutrons in AN atom of that element

4.An element's atomic number is equal to the number of protons in the nuclei of any of its atoms

5. Number of Protons = Atomic Number

Number of Electrons = Number of Protons = Atomic Number

Number of Neutrons = Mass Number - Atomic Number

For krypton:

Number of Protons = Atomic Number = 36

Number of Electrons = Number of Protons = Atomic Number = 36

Number of Neutrons = Mass Number - Atomic Number = 84 - 36 = 48

6. electron, lightest stable subatomic particle known. It carries a negative charge of 1.602176634 × 10−19 coulomb, which is considered the basic unit of electric charge. The rest mass of the electron is 9.1093837015 × 10−31 kg

7.The center of the atom is called a nucleus

8. Negatively charged particles are found in multiple layers outside the nucleus of the atom. These particles are called electrons, and they orbit in various energy levels around the atom's nucleus.

9. A charged particle is also called an ion

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Which of the following choices would have a positive entropy change?

aalyn [17]

Answer:

The option B) Fe₂O₃ (s) + 3C(s) → 2Fe(s) + 3CO₂(g), because the reactants are only solid units and the products contain gas molecules.

Explanation:

A positive entropy change means that the entropy of the products is greater than the entropy of the reactants.

Entropy in a measure of the radomness or disorder of the system.

Let's see every reaction:

A) 4NO₂ (g) + 2 H₂O (l) + O₂ (g) → 4 HNO₃ (aq)

Since 5 molecules of a gas (high disorder) combines with 2 molecules of liquid to produce 4 units of aqueous HNO₃ you may expect that the product is more ordered than the reactants, which means that the change in entropy is negative (the entropy decreases).

B) Fe₂O₃ (s) + 3C(s) → 2Fe(s) + 3CO₂(g)

The left side (reactants) show only solid substances which is a highly ordered arrangement while the right side (products) show the formation a solid (ordered arrangement) and a gas (highly disoredered arrangement), so you can predict the increase of the system entropy, i.e. a positive entropy change.

The equation C) shows the combination of 12 gas molecules to produce 1 solid and 6 gas molecules, so you can expect that the entropy will decrease, i.e. a negative entropy change.

For equation D) the products include solid and gas reactants while the product is just one unit of solid substance, letting you to predict a negative entropy change.

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koban [17]

Answer:

Food testing.

Beverage testing.

Drug testing.

Forensic testing.

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3 years ago

Read 2 more answers

the elements carbon hydrogen and oxygen are all part of the same blank on the periodic table........ i i think GROUP diangol row

Mrrafil [7]

The elements Carbon, Hydrogen, and Oxygen are all part of Non-Metals.

Hope This Helps! :)

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3 years ago

What is family and it's importance

Rus_ich [418]

Answer:

<h2>FAMILY:</h2>

Family is defined as a specific group of people that may be made up of partners, children, parents, aunts, uncles, cousins and grandparents. An example of a family is a set of parents living with their children. The definition of family is the group of people who share common ancestors.

<h2>IMPORTANCE:</h2>

Family is very important part of our everyday life. It helps us in improving our personality. It also helps us in shaping our life. It teaches us the value of love, affection, care, truthfulness and self-confidence and provides us tools and suggestions which are necessary to get success in life. Family is a place where you can be yourself. It is a place where you are accepted for what you are. This is where you are completely tension free and everyone is there to help you. Family encourages you when you are surrounded by problems. It helps you survive through tough times and bring joy and happiness into life.

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3 years ago

The table shows a chemical equation and the dimensional analysis used by a student to calculate the number of moles of Ba3N2 req

a_sh-v [17]

Answer:

c 3 mol of Ba(OH)₂ and 1 mol of Ba₃N₂ should be interchanged

Explanation:

Ba₃N₂ + 6H₂O → 3Ba(OH)₂ + 2NH₃

n/mol: 9.2

$\text{Moles of Ba$_{3}$N}_{2} = \text{9.2 mol Ba(OH)}_{2} \times \dfrac{\text{1 mol Ba$_{3}$N}_{2}} {\text{3 mol Ba(OH)}_{2}}= \text{x mol Ba$_{3}$N}_{2}$

They want to find moles of Ba₃N₂, so that should be in the numerator of the conversion factor,

Moles of Ba(OH)₂ should be in the denominator to cancel the units in 9.2 mol Ba(OH)₂,

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