Answer:
The mass of copper(II) sulfide formed is:
= 81.24 g
Explanation:
The Balanced chemical equation for this reaction is :

given mass= 54 g
Molar mass of Cu = 63.55 g/mol

Moles of Cu = 0.8497 mol
Given mass = 42 g
Molar mass of S = 32.06 g/mol

Moles of S = 1.31 mol
Limiting Reagent :<em> The reagent which is present in less amount and consumed in a reactio</em>n
<u><em>First find the limiting reagent :</em></u>

1 mol of Cu require = 1 mol of S
0.8497 mol of Cu should require = 1 x 0.8497 mol
= 0.8497 mol of S
S present in the reaction Medium = 1.31 mol
S Required = 0.8497 mol
S is present in excess and <u>Cu is limiting reagent</u>
<u>All Cu is consumed in the reaction</u>
Amount Cu will decide the amount of CuS formed

1 mole of Cu gives = 1 mole of Copper sulfide
0.8497 mol of Cu = 1 x 0.8497 mole of Copper sulfide
= 0.8497
Molar mass of CuS = 95.611 g/mol


Mass of CuS = 0.8497 x 95.611
= 81.24 g
N2 should be the gas to effuse more slowly
Answer:
Hence option C is correct.
Explanation:
the process is osmosis a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.
so the answer for the this question will be There is a net flow of water from the 4% starch solution into the 10% starch solution because solvent (water) moving from low conc. (4 %) to high conc. (10%)
Hence option C is correct.
Diameter = 200pm
200pm -> mm
200pm *^-12 / 1*10^-3 = .0000002
2.0*10-7x mm = 1.0mm
Divide x on both sides
Fe + heat ----> Fe_54 + + neutrons