0.45 g of hydrated sodium carbonate crystals were heated until 3.87 of anhydrous power remained. How many moles of water are there in one mole of hydrated salt?

Formula of hydrated sodium carbonate : Na₂CO₃.10H₂O, so moles of water in one mole of hydrated salt = 10

Hydrate is a compound that binds water (H₂O), usually in the form of crystals/ solids

If these compounds are dissolved in water or heated, the hydrates can decompose:

Example: X.YH₂O (s) → X (aq) + YH₂O (l)

The formula for the hydrated compound contains: YH2O

The mole ratio shows the ratio of the coefficients of the hydrate compound

10.45 hydrated sodium carbonate(Na₂CO₃.xH₂O) were heated until 3.87 of 3.87of anhydrous (Na₂CO₃) remained, so

mass H₂O released :

mass Na₂CO₃ = 3.87 g

mol ratio Na₂CO₃(MW= g/mol) : H₂O(MW=18 g/mol) =

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.