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Keith_Richards [23]
2 years ago
6

PLS ANSWER ALL QUESTIONS FOR 67 POINTS

Chemistry
1 answer:
Elena L [17]2 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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The decomposition of NI3 to form N2 and I2 releases −290.0 kJ of energy. The reaction can be represented as 2NI3(s)→N2(g)+3I2(g)
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Answer:

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

Explanation:

Mass of nitrogen triiodide = 20.0 g

Moles of nitrogen triiodide = \frac{20.0 g}{395 g/mol}=0.05063 mol

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According to reaction, 2 moles of nitrogen triiodide gives 290.0 kilo Joules of heat on decomposition ,then 0.05063 moles of nitrogen triiodide will give :

\frac{-290.0 kJ}{2}\times 0.05063=-7.34 kJ

-7.34 kilo Joules is the change in enthaply when 20.0 grams of nitrogen triiodide decomposes.

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This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): An analytical chemist has det
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Answer:

0.054 mol O

Explanation:

<em>This is the chemical formula for acetic acid (the chemical that gives the sharp taste to vinegar): CH₃CO₂H. An analytical chemist has determined by measurements that there are 0.054 moles of carbon in a sample of acetic acid. How many moles of oxygen are in the sample?</em>

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Step 1: Given data

  • Chemical formula of acetic acid: CH₃CO₂H
  • Moles of carbon in the sample: 0.054 moles

Step 2: Establish the appropriate molar ratio

According to the chemical formula, the molar ratio of C to O is 2:2.

Step 3: Calculate the moles of oxygen in the sample

We will use the molar ratio to determine the moles of oxygen accompanying 0.054 moles of carbon.

0.054 mol C × (2 mol O/2 mol C) = 0.054 mol O

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I believe the answer is "b". "During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis."

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