The reaction between Ba(OH)2 and NH4SCN is endothermic and the enthalpy change (ΔH) is positive. This is because the reaction absorbs heat from the surrounding environment, causing the temperature to drop. The ΔH is positive in this type of endothermic reaction.
When solids Ba(OH)2 and NH4SCN are mixed, a solution is produced and the temperature drops. This indicates that the reaction is endothermic, which means it absorbs heat from the surroundings. As a result, the surroundings (or in this case the solution) will experience a decrease in temperature. According to the conventions used in chemistry, in an endothermic reaction, the enthalpy change (ΔH) is positive. Hence, the correct statement about the energetics of this particular reaction is: 'The reaction is endothermic and ΔH is positive.'
When considering the enthalpy change of a reaction, it's also key to understand that an exothermic reaction results when the bonds in the products are stronger than the bonds in the reactants - this is characterized by a negative ΔH (heat is released). In contrast, bonds in the products of an endothermic reaction are weaker than in the reactants, resulting in a positive ΔH (heat is absorbed).
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2. Bio Chemistry
3. Organic Chemistry
4. Inorganic Chemistry
Answer:
Organic chemistry
Explanation:
The correct answer is False
Explanation:
A limiting factor refers to a condition that stops or limits the growth of a population of any species. Some of these factors include the availability of sources such as food, shelter or water; predation; natural weather conditions; natural disasters; and competence.
The previous idea implies food is not the only factor or condition that would stop or limit the growth of a population but there are many other factors that could prevent a population from growing too large, this includes abiotic factors (nonliving condition) such as weather and biotic factors (living condition) such as competition with other species or individuals or predation.
Food is not the only limiting factor that keeps populations from growing too large. This statement is false.
Populations are regulated by a variety of factors, including but not limited to food availability. These factors can be categorized into two main types: density-dependent and density-independent factors.
Density-dependent factors are influenced by population size and include factors such as competition for resources (including food), predation, disease, and territoriality.
As a population grows, competition for limited resources, including food, increases. This can lead to reduced growth, increased mortality, and ultimately limit the population's size.
Thus, while food availability is an important factor in population dynamics, it is not the sole limiting factor. Other ecological factors and interactions within the ecosystem play significant roles in regulating population size and preventing populations from growing too large.
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Buffer capacity is defined as the capacity of a buffer to resist changes in pH upon addition of an acid or a base. The buffer capacity is high when the concentration of the acid and its conjugate base is high, and the pH of the solution is near the pKa value of the weak acid.
The greater the buffer capacity, the better it can resist pH changes upon addition of an acid or base. The buffer capacity of a solution is highest when the pH is near the pKa value of the weak acid.
A buffer is a solution that has the ability to resist changes in pH upon the addition of an acid or base. The buffer capacity is highest when the pH of the buffer is close to the pKa of the weak acid component in the buffer. Therefore, the buffer capacity is the highest when the pH is equal to the pKa value of the weak acid.
Therefore, the solution with the greatest buffer capacity is the one with the highest concentration of both the weak acid and its conjugate base, which can resist the changes in pH with the addition of an acid or base.
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Answer:
The correct option is: Potassium
Explanation:
Sodium, Potassium, Rubidium and Caesium are referred to as the alkali metals that belong to the group 1 of the periodic table, thus having one valence electron in their outer or valence shell.
Sodium, atomic number 11, belongs to the period 3 of the periodic table. It has three shells and the number of electrons per shell is 2, 8, 1.
Potassium, atomic number 19, belongs to the period 4 of the periodic table. It has four shells and the number of electrons per shell is 2, 8, 8, 1.
Rubidium, atomic number 37, belongs to the period 5 of the periodic table. It has five shells and the number of electrons per shell is 2, 8, 18, 8, 1.
Caesium, atomic number 37, belongs to the period 6 of the periodic table. It has six shells and the number of electrons per shell is 2, 8, 18, 18, 8, 1.
Therefore, Potassium, atomic number 19, has four shells or energy levels.
Among the given options, the element that has four energy levels is potassium (K). The correct answer is option 2.
An energy level is a specific amount of energy that an electron in an atom can possess.
The electronic configurations of Na (sodium), K (potassium), Cs (cesium), and Rb (rubidium) are as follows:
Na:
K:
Cs:
Rb:
The above electronic configurations shows that only Potassium has 4 energy levels while Na has 3 energy levels, Cs has 6 energy levels and Rb has 5 energy levels.
Therefore, the correct answer is option 2. Potassium (K) has four energy levels.
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