Use the grams to moles first. The molar mass of sodium is 22.99g, so 10/22.99 ≈ 0.43 moles. The use moles to atoms conversions. 0.43 x (6.022 x 10^23), which would be about 2.62 x 10^23 atoms in 10g of sodium.
<h3>
Answer:</h3>
0.130 moles NH₃
<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Atomic Structure</u>
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[Given] 7.85 × 10²² molecules NH₃
[Solve] moles NH₃
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
- [DA] Set up:

- [DA] Multiply/Divide [Cancel out units]:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 3 sig figs.</em>
0.130355 moles NH₃ ≈ 0.130 moles NH₃
A.) In the beginning the universe was too hot for atoms to exist.
Because choice b,c,and d are all part of the big bang theory.