1. The answer is option E, that is None of the above is correct.
As a polymer becomes more crystalline,
its melting point doesn't decreases, its density doesn't decreases, its stiffness doesn't decreases and its yield stress doesn't decreases.
2. The answer is option B, that is the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.
In the smectic A liquid-crystalline phase, molecules are arranged in sheets, with their long axes parallel and their ends aligned as well.
3. For a substitutional alloy to form, the two metals combined must have similar atomic radii and chemical bonding properties.
Answer:
d. the conjugate base of the weak acid
Explanation:
The strong base (BOH) is completely dissociated in water:
BOH → B⁺ + OH⁻
The resulting conjugate acid (OH⁻) is a weak acid, so it remains in solution as OH⁻ ions.
By other hand, the weak acid (HA) is only slightly dissociated in water:
HA ⇄ H⁺ + A⁻
The resulting conjugate base (A⁻) is a weak base. Thus, it reacts with H⁺ ions from water to form HA, increasing the concentration of OH⁻ ions in the solution.
Therefore, the resulting solution will have a pH > 7 (basic).
Answer is: <span>concentration of fluoride in the water in parts-per-million is 1 ppm.
</span>Parts-per-million (10⁻⁶) is<span> present at one-millionth of a </span>gram per gram of sample solution, f<span>or example mg/kg.
</span>m(fluoride) = 500 g · 1000 mg/g = 500000 mg.
m(water) = d(water) · V(water).
m(water) = 1 kg/L · 500000 L.
m(water) = 500000 kg.
arts-per-million = 500000 mg ÷ 500000 kg = 1 mg/kg = 1 ppm.
Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.
Ex: cutting a paper, gaining weight, cutting hair
Answer:
exothermic
Explanation:
This chemical reaction is an exothermic reaction because heat is liberated into the environment.
In organic chemistry, the reaction is termed a combustion reaction. In such a reaction, a fuel combines with oxygen to produce carbon dioxide and water.
It is an energy transformation from chemical energy to heat energy.
- An exothermic reaction is one in which heat is liberated to the surrounding.
- The surrounding becomes hotter at the end of the reaction.
In the reaction depicted, heat is liberated.
