The properties of a compound are nothing like the properties of th elements that combine to make it.
sodium chloride,NaCl, table salt, is a white cubic crystal, stable ionic compound, soluble in water
sodium is a soft metal, very reactive with water and air
chlorine is a yellow green gas that is poisonous and very reactive.
carbon dioxide, CO2, is a clear, colorless gas that puts out fires, plants use but we breath out.
carbon is a black solid, or a diamond
oxygen is a clear colorless gas that is needed for burning and breathing.
The limiting reactant is the substance of the reactants that runs out first. The excess reactant is the substance with the greater amount than necessary to react completely with the limiting reactant after a chemical reaction.
Gilbert N. Lewis (1875-1946) was an American physical chemist.
His work with heavy water and resources were adapted by Ernest Lawrence in the development of the cyclotron.
SCIENTIFIC CONTRIBUTIONS
Lewis made many contributions to science. He was nominated for the Nobel Prize 41 times, though he was never awarded the prize.
He discovered covalent bonds and electron pairs. He worked with isotope separation, and became the first person to purify a sample of heavy water. The heavy water was later used as projectiles in Lawrence’s 27-inch cyclotron.
He also made contributions in ideas on relativity and acid-base reactions and coined the term “photon” as the smallest unit of light.
Answer:
1.385 × 10²³ atoms of calcium
Explanation:
Given data:
Number of moles of calcium = 0.23 mol
Number of atoms = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 0.23 mole of calcium:
one mole = 6.022 × 10²³ atoms of calcium
0.23 × 6.022 × 10²³ atoms of calcium
1.385 × 10²³ atoms of calcium
