If sufficient acid is used to react completely with 21.0 grams of Mg

Mg(s) + 2 HCl(aq) + MgCl2(aq) + H2(g)

what volume of hydrogen at STP would be
produced?

1. 9.68 liters
2. 10.60 liters
3. 4.84 liters
4. 19.37 liters
5. 22.40 liters

Solution,

Mass of Mg - 21gm

molar mass of Mg - 24gm

moles = Given mass/ Molar mass

moles = 21/24 = 0.875

1 mole of Mg produce 1 mole of H2 gas

so 0.875 mole of Mg will produce 0.875 moles of H2 gas

One mole of H2 gas = 22.4 litre

0.875 mole of H2 gas = 0.875×22.4

0.875 mole of H2 gas = 19.60 litre

So the nearest ANSWER is Option four 19.37 litre.

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .