Chemistry Ch. 14/ solutions
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- What are the three ways solid, liquid, or gas can be characterized?
- Element, compound, or mixture
- What is an element?
- 1 entity by itself with its own properties, can be 1 or more but must be same atom
- What is a compound?
- 2 or more different elements
- What is a mixture?
- random mixing of either elements or compounds, or both not in a fixed ratio
- What are the characteristics of compounds?
- must be seperated by chemical means; properties are unique, ratio of elements are fixed
- What is heterogenous?
- need not see seperate boundaries in mixture
- What are the characteristics of heterogenous mixtures?
- visible with eye or with microscope; separated by filtration
- What is homogenous?
- composition and properties of mixture are uniformed
- What are the characteristics of homogenous mixtures?
- consists of ions and compounds; need powerful means to visualize; uniform phase; requires seperation by chemical means
- What is the solvent?
- Compound present in largest quantities
- What is the solute?
- compounds present is smaller quantities
- What 3 things must happen when dissolving a solute?
-
1- solute seperates
2- solvent seperates
3- both mix
(requires energy) - What decides if reaction of endothermic or exothermic?
- values of enthalpy (H) of solute + (H) of solvent + (H) of mix. endothermic= > 0, exothermic= < 0
- What is enthalpy of solvation?
-
(H) of solvent and (H) of mix
(called H of hydration of solution is aqeous) - What are the steps of enthalpy of solvation?
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1- H bonds are broken (endothermic)
2- Formation of Ion dipole (exothermic) - What does (H) of hydration depend upon?
- charge density of ion, which is the ratio of charge to volume of ion. smaller the ion= greater hydration energy b/c more solvent surrounds ion