<h3>
Answer:</h3>
0.0463 mol KCl
<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>
- Reading a Periodic Table
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
3.45 g KCl
<u>Step 2: Identify Conversions</u>
Molar Mass of K - 39.10 g/mol
Molar Mass of Cl - 35.45 g/mol
Molar Mass of KCl - 39.10 + 35.45 = 74.55 g/mol
<u>Step 3: Convert</u>
- Set up:
- Multiply/Divide:
<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 3 sig figs.</em>
0.046278 mol KCl ≈ 0.0463 mol KCl
Answer:
XY would have a higher melting point than NaCl.
Explanation:
The electrostatic force (F) between ions in an ionic lattice can be estimated using Coulomb's Law.
where,
k is the Coulomb's constant
q₁ and q₂ are the charges of the ions
r is the distance between the ions
X⁺⁺ and Y⁻⁻ are doubly charged with respect to Na⁺ and Cl⁻ so the force between them is 4 times the force between Na⁺ and Cl⁻. Since the force is stronger, it would require more energy to break it to take it to the liquid state, so a higher melting point is expected.
For this problem, we use the Beer Lambert's Law. Its usual equation is:
A = ∈LC
where
A is the absorbance
∈ is the molar absorptivity
L is the path length
C is the concentration of the sample solution
As you notice, we only have to find the absorbance. But since we are not given with the molar absorptivity, we will have to use the modified equation that relates % transmittance to absorbance:
A = 2 - log(%T)
A = 2 - log(27.3)
A = 0.5638
Only when it is found in the atmosphere, because it will create a hole, letting strong UV rays shine down on earth, heating it up, and causing skin cancer in humans and other animals.
