Answer:

Explanation:
(a) Balanced equation
Cu + 2AgNO₃ ⟶ Cu(NO₃)₂+ 2Ag
(b) Calculation
You want to convert atoms of Cu to atoms of Ag.
The atomic ratio is ratio is 2 atoms Ag:1 atom Cu

The appropriate answer is B. Has no atmosphere. Neptune is a gas giant and is the eight planet in the solar system. It has a thick atmosphere consisting of hydrogen, helium and methane. Neptune has at least eight moons with Triton being the largest.
Neptune has four rings which circle the planet. The rings are made of dust particles, similar to the rings of Saturn.
A molecular structure is a shape of a molecule, a three-dimensional shape or configuration of a molecule that is dependent on the preferred spatial orientation of covalent bonds to atoms having two or more partners. Attached is the diagram for the molecular structure of So42
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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