How do i do question number 3? and what is the answer?

60.02 g.

Explanation:

Mg + 2HCl → MgCl₂ + H₂.

that 1.0  mole of Mg reacts with 2.0 moles of HCl to produce 1.0 mole of MgCl₂ and 1.0 moles of H₂.

no. of moles of Mg = mass/atomic mass = (20.0 g)/(24.3 g/mol) = 0.823 mol.

∴ 0.833 mol of Mg will react with (2 x 0.833 mol = 1.646 mol) of HCl.

∴ The mass of reacted HCl = no. of moles x molar mass = (1.646 mol)(36.46 g/mol) = 60.02 g.

(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