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:
d. Hydrophobic molecules are attracted to each other.
Explanation:
The term “hydrophobic effect” is associated with the spontaneous tendency of macromolecules, such as proteins, to prefer a conformation in an aqueous medium, with hydrophobic groups facing the interior of the mac romolecule, favoring attractive intramolecular interactions, and hydrophilic groups exposed on the surface, for maximize interactions with water molecules in the medium. This is because the hydrophobic molecules are attracted to each other, allowing them to turn inward.
Answer:
1) After adding 15.0 mL of the HCl solution, the mixture is before the equivalence point on the titration curve.
2) The pH of the solution after adding HCl is 12.6
Explanation:
10.0 mL of 0.25 M NaOH(aq) react with 15.0 mL of 0.10 M HCl(aq). Let's calculate the moles of each reactant.
There is an excess of NaOH so the mixture is before the equivalence point. When HCl completely reacts, we can calculate the moles in excess of NaOH.
NaOH + HCl ⇒ NaCl + H₂O
Initial 2.5 × 10⁻³ 1.5 × 10⁻³ 0 0
Reaction -1.5 × 10⁻³ -1.5 × 10⁻³ 1.5 × 10⁻³ 1.5 × 10⁻³
Final 1.0 × 10⁻³ 0 1.5 × 10⁻³ 1.5 × 10⁻³
The concentration of NaOH is:
![[NaOH]=\frac{1.0 \times 10^{-3} mol }{25.0 \times 10^{-3} L} =0.040M](https://tex.z-dn.net/?f=%5BNaOH%5D%3D%5Cfrac%7B1.0%20%5Ctimes%2010%5E%7B-3%7D%20mol%20%7D%7B25.0%20%5Ctimes%2010%5E%7B-3%7D%20L%7D%20%3D0.040M)
NaOH is a strong base so [OH⁻] = [NaOH].
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log 0.040 = 1.4
pH = 14 - pOH = 14 - 1.4 = 12.6
Evidence could be gathered in the future that contradicts original theories. <span>Phenomena cannot be proven by conclusive evidence in science because, as of now, the evidence isn't conclusive. It is speculation. Just as a phenomena cannot be proven, it also cannot be disproven. </span>
Answer:
E = 29.7× 10⁻²⁰ j
Explanation:
Given data;
Frequency of light = 4.48 × 10¹⁴ Hz
Energy of photon = ?
Solution:
Formula:
E = h.f
E = energy of photon
h = planck's constant
f = frequency
E = h.f
E = 6.63 × 10⁻³⁴ Kg.m² /s × 4.48 × 10¹⁴ s⁻¹
E = 29.7× 10⁻²⁰ Kg.m²/s²
Kg.m²/s² = j
E = 29.7× 10⁻²⁰ j
