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olga nikolaevna [1]
2 years ago
10

I need help with this someone help

Chemistry
1 answer:
allochka39001 [22]2 years ago
6 0

Answer:

1. Element is Ca

2. 20 electrons

3. 2 valence electrons

4. 4 energy levels

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4. How many moles of gold (Au) are in a pure gold nugget having a mass of 25.0 grams.
ikadub [295]
<h3>Answer:</h3>

0.127 mol Au

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

  • Reading a Periodic Table
  • Moles

<u>Stoichiometry</u>

  • Using Dimensional Analysis
<h3>Explanation:</h3>

<u>Step 1: Define</u>

[Given] 25.0 g Au

[Solve] moles Au

<u>Step 2: Identify Conversions</u>

[PT] Molar Mass of Au - 196.97 g/mol

<u>Step 3: Convert</u>

  1. [DA] Set up:                                                                                                     \displaystyle 25.0 \ g \ Au(\frac{1 \ mol \ Au}{196.97 \ g \ Au})
  2. [DA] Multiply/Divide [Cancel out units:                                                          \displaystyle 0.126923 \ mol \ Au

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

0.126923 mol Au ≈ 0.127 mol Au

3 0
2 years ago
Read 2 more answers
Why is water said to be universal solvent?
Pachacha [2.7K]

Answer:

B

Explanation:

And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This allows the water molecule to become attracted to many other different types of molecules.

8 0
2 years ago
Read 2 more answers
Anyone here im getting bored feel​
xxTIMURxx [149]

Yeah im here and i am alos getting bored to

what are you doing and how is your day ?

5 0
2 years ago
Read 2 more answers
A researcher measures the equilibrium separation between two flat hydrophilic mica plates in a solution of non-ionic surfactant.
svet-max [94.6K]

Answer:

See explaination and attachment

Explanation:

please kindly see attachment for the step by step solution of the given problem.

3 0
3 years ago
Arrange the following chloroarenes in increasing order of their reactivity in nucleophilic substitution to form their correspond
pantera1 [17]
The question is incomplete. Complete question is attached below
..............................................................................................................................

Correct Answer: Option C i.e. I ~ III < IV < V < II

Reason:
During a nucleophilic subsitution reaction of chloroarenes, Cl- group is replaced by an nucleophile like OH-.

Order of reactivity, during such reactions depends on the electron density on carbon atom that is attached to Cl. Lower the electron density, greater will be the reactivity.

Among the provided chloroarenes, electron density on C atom will be minimum in case of compound II, because of presence of electron withdrawing group (-NO2) at ortho and para position. Due to this, there will be large number of resonating structures. This signifies greater electron de-localization, and hence largest reactivity for nucleophilic substitution reaction.

Followed by this, compound V will show greater reactivity, due to presence of -NO2 group at para and one of the ortho position. Compound IV will have less number of resonating structures as compared to compound II and V, hence it will display poor reactivity towards nucleophilic substitution reaction.

Finally, compound 1 and III will minimum reactivity towards nucleophilic substitution reaction, because -NO2 group present at meta position (compound III) will not participate in resonance.  



6 0
3 years ago
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