Hydrogen gas can be prepared in the laboratory by a sin- gle-displacement reaction in which solid zinc reacts with hydrochloric acid. How much zinc in grams is required to make 14.5 g of hydrogen gas through this reaction

941 g

Explanation:

Step 1: Write the balanced equation

Zn + 2 HCl ⇒ ZnCl₂ + H₂

Step 2: Calculate the moles corresponding to 14.5 g of H₂

The molar mass of H₂ is 1.01 g/mol.

14.5 g × 1 mol/1.01 g = 14.4 mol

Step 3: Calculate the number of moles of Zn required to form 14.4 moles of H₂

The molar ratio of Zn to H₂ is 1:1. The moles of Zn required are 1/1 × 14.4 mol = 14.4 mol.

Step 4: Calculate the mass corresponding to 14.4 moles of Zn

The molar mass of Zn is 65.38 g/mol.

14.4 mol × 65.38 g/mol = 941 g

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g