Imagine a chemist is in the lab and trying to make some chemical reactions happen. In one reaction she reacts chemicals in an exothermic reaction and there is an increase in entropy. A second chemical reaction she is trying to run is endothermic and there is a decrease in entropy. Which of the two reactions is more likely to occur and why?
Answer:
1.047 M
Explanation:
The given reaction:

For dichromate :
Molarity = 0.254 M
Volume = 15.8 mL
The conversion of mL to L is shown below:
1 mL = 10⁻³ L
Thus, volume = 15.8 ×10⁻³ L
Thus, moles of dichromate :

Moles of dichromate = 0.0040132 moles
1 mole of dichromate react with 6 moles of iron(II) solution
Thus,
0.0040132 moles of dichromate react with 6 × 0.0040132 moles of iron(II) solution
Moles of iron(II) solution = 0.02408 moles
Volume = 23 mL = 0.023 L
Considering:

<u>Molarity = 0.02408 / 0.023 = 1.047 M</u>
<h3>
Answer:</h3>
0.127 mol Au
<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<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>
- [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>
0.126923 mol Au ≈ 0.127 mol Au