Answer:
d = 43.5 g/cm³
Explanation:
Given data:
Mass of magnesium cube = 217.501 g
Volume of magnesium cube = 5.00 cm³
Density of magnesium cube = ?
Solution:
Formula:
d = m/v
d = density
m = mass
v = volume
by putting values,
d = 217.501 g/ 5.00 cm³
d = 43.5 g/cm³
An exergonic reaction is a chemical reaction where the change in the free energy is negative (there is a net release of free energy),[1] indicating a spontaneous reaction. For processes that take place under constant pressure and temperature conditions, the Gibbs free energy is used whereas the Helmholtz energy is used for processes that take place under constant volume and temperature conditions.
Symbolically, the release of free energy, G, in an exergonic reaction (at constant pressure and temperature) is denoted as
{\displaystyle \Delta G=G_{\rm {products}}-G_{\rm {reactants}}<0.\,}
Although exergonic reactions are said to occur spontaneously, this does not imply that the reaction will take place at an observable rate. For instance, the disproportionation of hydrogen peroxide is very slow in the absence of a suitable catalyst. It has been suggested that eager would be a more intuitive term in this context.[2]
More generally, the terms exergonic and endergonic relate to the free energy change in any process, not just chemical reactions. An example of an exergonic reaction is cellular respiration. This relates to the degrees of freedom as a consequence of entropy, the temperature, and the difference in heat released or absorbed.
By contrast, the terms exothermic and endothermic relate to the overall exchange of heat during a process
A buffer solution contains an equivalent amount of acid and base. The pH of the solution with an acid dissociation constant (pKa) value of 3.75 is 3.82.
<h3>What is pH?</h3>
The amount of hydrogen or the proton ion in the solution is expressed by the pH. It is given by the sum of pKa and the log of the concentration of acid and bases.
Given,
Concentration of salt [HCOO⁻] = 0.24 M
Concentration of acid [HCOOH] = 0.20 M
The acid dissociation constant (pKa) = 3.75
pH is calculated from the Hendersons equation as,
pH = pKa + log [salt] ÷ [acid]
pH = 3.75 + log [0.24] ÷ [0.20]
= 3.75 + log (1.2)
= 3.75 + 0.079
= 3.82
Therefore, 3.82 is the pH of the buffer.
Learn more about pH here:
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Answer:
D. Surface tension.
Explanation:
Surface tension is defined as the energy required to increase the surface area of a liquid by a unit amount.
The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules:
A molecule in a liquid experiences cohesive forces with other molecules in all directions while molecules at the surface of a liquid experiences only net inward cohesive forces.
The more UV rays reach the earth
