Answer 1
The sample will dissolve in more than 1 minute.
Explanation :-
Generally Solubility and rate of solubility of substances increase with the increase in temperature. So lower the temperature less fast will it dissolve in the same amount of water.
Since at 50 C it takes 1 minute to dissolve, at 20 C which is lower temperature it will take more time to dissolve.
Answer 2
Transition metals
Explanation:-
Hardness depends on the extent of metallic bonding for metals. More the number of electrons more the metallic bonding.
Alkali metals with just 1 valence electron have weak metallic bonding. Alkaline earth metals have just 2 valence electrons. Transition elements has more electrons in penultimate shell and valence shell than lanthanides. Transition metals with most metallic bonding are the hardest
Seems to be 3.6 since it’s closer by 1, As for 4.0 it would be 5 more.
The lone pairs on the oxygen in the following compound are best described as: <u>one localized and one delocalized</u>
<h3>Lone pair electron</h3>
A lone pair electron is valence shell electron pair associated with one atom, and not part of a covalent bond.
Within the context of this question, the oxygen atom of water for instance has two lone pair of which one of them is localized and other one is delocalized
Learn more about lone pair electrons:
brainly.com/question/3915115
Oxygen, silicon, calcium, magnesium, potassium and sodium
Answer:
The reaction has a single reactant
Explanation:
Decomposition reaction is a reaction in which an insoluble single compound is heated at a high temperature and decomposes into several products.
Typically, we may see decomposition of calcium carbonate producing calcium oxide and carbon dioxide, this is represented by the following reaction:

Another example would be decomposition of ammonium nitrite. Ammonium nitrite would decompose into nitrogen and water:

Notice that the two examples above share something in common: the two decomposition reactions have a single reactant.