A beaker contains dissolved NH4Cl, and another beaker contains dissolved Pb(NO3)2. When the two solutions are mixed together, a precipitate forms. What are the spectator ions

Explanation:

The reaction of precipitation between NH₄Cl and Pb(NO₃)₂ is the following:

2NH₄Cl(aq) + Pb(NO₃)₂ → NH₄NO₃(aq) + PbCl₂(s)

The formed precipitate is PbCl₂ because it is an insoluble salt. The following ionic equation shows the spectator ions:

2NH₄⁺(aq) + 2Cl⁻(aq) + Pb²⁺(aq) + 2 NO₃⁻(aq) → 2NH₄⁺(aq) + 2NO₃⁻(aq) + PbCl₂(s)

The precipitate (PbCl₂) is formed by the Pb²⁺ ion and the Cl⁻ ion. Thus, the spectator ions are those which do not form the precipitate. In this case, they are: NH₄⁺ (ammonium ion) and NO₃⁻ (nitrate ion).

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied