Answer:
D. a reactant that is catalyzed by an enzyme
Explanation:
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The answer is homogeneous
The answer to this question would be: alkaline earth metal
Alkali earth metal is the second column group of the periodic table. In this group, the element has 2 extra electrons in their outer cells. That is why most of this metal has 2+ charge.
Their neighbor is the alkali metal which was the first column of the periodic table. The name is similar so don't confused and mix them each other.
Answer:

Explanation:
Hello!
In this case, we can divide the problem in two steps:
1. Dilution to 278 mL: here, the initial concentration and volume are 1.20 M and 52.0 mL respectively, and a final volume of 278 mL, it means that the moles remain the same so we can write:

So we solve for C2:

2. Now, since 111 mL of water is added, we compute the final volume, V3:

So, the final concentration of the 139 mL portion is:

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Answer:
ΔS> 0 means Letter A
Explanation:
Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, we may reach a significant conclusion regarding the relation between this property and spontaneity. In thermodynamic models, the system and surroundings comprise everything, that is, the universe, and so the following is true:
\displaystyle \Delta {S}_{\text{univ}}=\Delta {S}_{\text{sys}}+\Delta {S}_{\text{surr}}