Asolution containing a mixture of metal cations was treated with dilute hcl and no precipitate formed. next, h2s was bubbled through the acidic solution. a precipitate formed and was filtered off. then, the ph was raised to about 8 and h2s was again bubbled through the solution. a precipitate again formed and was filtered off. finally, the solution was treated with a sodium carbonate solution, which resulted in no precipitation. which metal ions were definitely present, which were definitely absent, and which may or may not have been present in the original mixture?

Explanation:

If you follow the statements carefully the only ions you can rule out as being "Definitely not present" are: Cr3+, Fe3+, and Zn2+ . The rest of the ions should be categorized under "Possibly present", as we cannot determine if any of the ions are "Definitely present".

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-