HardChemistryHigh School (11–12)The p-Block ElementsNumerical

A flask holds a mixture of 6.41 g of calcium carbide (64.10 g/mol) and 2.88 g of aluminium carbide…

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

A flask holds a mixture of $6.41\ \text{g}$ of calcium carbide ( $64.10\ \text{g/mol}$ ) and $2.88\ \text{g}$ of aluminium carbide ( $143.96\ \text{g/mol}$ ). Excess water is added: $\text{CaC}_{2} + 2\text{H}_{2}\text{O} \to \text{Ca}(\text{OH})_{2} + \text{C}_{2}\text{H}_{2}$ and $\text{Al}_{4}\text{C}_{3} + 12\text{H}_{2}\text{O} \to 4\text{Al}(\text{OH})_{3} + 3\text{CH}_{4}$ . Take $22.4\ \text{L/mol}$ at $273\ \text{K}$ and $1\ \text{atm}$ , and $78.00\ \text{g/mol}$ for aluminium hydroxide. Find the volumes of acetylene and of methane, and the mass of aluminium hydroxide that forms.

Need a reminder? The key ideaShow

Count the oxides by their character: acidic, amphoteric, basic, neutral. Red lead forms by $6\text{PbO} + \text{O}_{2} \to 2\text{Pb}_{3}\text{O}_{4}$ and splits with nitric acid by $\text{Pb}_{3}\text{O}_{4} + 4\text{HNO}_{3} \to 2\text{Pb}(\text{NO}_{3})_{2} + \text{PbO}_{2} + 2\text{H}_{2}\text{O}$ . Carbides give gases with water: $\text{CaC}_{2}$ gives acetylene, one mole for each mole, and $\text{Al}_{4}\text{C}_{3}$ gives methane, three moles for each mole.

The worked solution

Have you tried it?

Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

← All Problems

← A sample of 100.0 g of lead(II) oxide (223.20 g/mol) is heated in air at about 750 K until it is…A student studies four species: NH₄⁺, NCl₃, PCl₅ and N₂O₅… →

More onThe p-Block Elements

Discussion (0)

Loading…