Question

Calculate the number of Cao molecules in 2.8g of quicklime?

Answer 1

We were asked to find out the number of CaO molecules present in some amount of quicklime. We first discuss calcium oxide and how it is prepared. Then, we will find out the number of molecules present in 2.8g of molecules.

Complete step by step answer:
Calcium oxide (CaO), normally referred to as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline strong at room temperature. The extensively used term "lime" indicates calcium-containing inorganic materials, in which compounds such as carbonates, oxides and hydroxides of calcium, silicon, magnesium, aluminium, and iron are present in majority amounts. By comparison, quicklime particularly applies to the single chemical compound calcium oxide. Calcium oxide that survives processing without reacting in building merchandise which includes cement is known as unfastened lime.
$CaCO_3(s) \rightarrow CaO(s) + CO_2(g)$
Given that:
Mass of CaO $W = 2.8g$
Moles mass of CaO $M = 56g/mol$
$\text{Number of moles CaO n} = \dfrac{M}{W} = 562.8 mol = 0.05 moles$
$\text{ Number of molecules N} = n \times N_A = 0.05 \times 6.022 \times 1023 = 3.011 \times 1022 molecules$

Additional Information:
Quicklime is fantastically less expensive. The thermal decomposition of substances, which includes limestone or seashells, that comprise calcium carbonate ($CaCO_3$; mineral calcite) in a lime kiln results in the formation of Calcium Oxide. Limestone is an alternative to lime in many applications, which encompass agriculture, fluxing, and sulphur removal. Limestone, which includes less reactive fabric, is slower to react and may have other risks as compared with lime, relying on the utility; however, limestone is extensively much less steeply-priced than lime. Calcined gypsum is an opportunity cloth in industrial plasters and mortars. Cement, cement kiln dust, fly ash, and lime kiln dirt are capability substitutes for some creation uses of lime. Magnesium hydroxide is a substitute for lime in pH manipulation, and magnesium oxide is a substitute for dolomitic lime as a flux in steelmaking.
The quicklime is very unstable and, when cooled, will spontaneously react with $CO_2$ from the air till, after enough time, it is likely to be completely converted back to calcium carbonate unless slaked with water to set as lime plaster or lime mortar.

Note:
As the reaction of quicklime with water is highly vigorous, quicklime leads to intense irritation whilst inhaled or positioned in contact with wet skin or eyes. Inhalation might also cause coughing, sneezing, and working breathing. It can also then evolve into burns with perforation of the nasal septum, abdominal pain, nausea and vomiting. Although quicklime isn't considered a fireplace hazard, its response with water can release enough heat to ignite flammable substances.