Mass of Li = 237.38 g
<h3>Further explanation</h3>
The mole itself is the number of particles contained in a substance amounting to 6.02.10²³

<h3>Known</h3>
Moles of Li = 34.2
Molar mass(MW) of Li = 6.941 g/mol
then mass of Lithium (Li) :

B. 3.0 mol·L⁻¹ NaCl
Explanation:
Freezing point is a colligative property: it depends only on the number of particles in solution.
The for freezing point depression ΔT_f is
ΔT_f = iK_fb
where
i = the number of moles of particles available from one mole of solute
K_f = the molal freezing point depression constant
b = the molal concentration of the solute
All your solutions are aqueous NaCl. They differ only in their concentrations.
Thus, the most concentrated solution will have the greatest freezing point depression and the lowest freezing point.
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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
Plants
do. Good luck with whatever you are doing :)
Answer:ionic
Explanation: ionic bond formation
In the ionic bond formation between calcium and sulfur, a calcium atom donates two valence electrons to a sulfur atom to form a Ca2+ ion and an S2+ ⁻ ion.