Chapter 5: Textbook Flashcards
What is a solution?
A homogenous mixture of substances composed of at least solute (the substance that is dissolved) and one solvent (what the solute is dissolved in)
What is a solute?
A substance that is dissolved, such as salt
What is a solvent?
The medium in which the solute is dissolved, such as water
Why do some mixtures appear opaque or translucent?
Because they contain undissolved particles large enough to block or scatter lightwaves. This would be called a heterogenous mixtureq
If you were to do a chemical analysis of a homogeneous substance, what would you find in terms of proportions?
The proportion of each chemical will remain the same, regardless of the size of the sample. Because of the idea that there is a uniform mixture of entities in a solution
Empirically, what would classify as homogeneous?
A solution that is uniform at the atomic and molecular levels
What state can solutes and solvents be in?
Solid, liquid or gas
In metal alloys such as bronze, what state is dissolving done in?
It is done in liquid form before the substance is put into solid form
What is the solution of gasoline composed of?
It is a mixture of many different hydrocarbons that form a solution at the molecular level
What is an example of a liquid dissolved in a liquid?
Methanol in water to make antifreeze
What is an example of a solid dissolved in a solid?
Tin in copper to make bronze
What is an example of liquids and solvents dissolving in a solvent other than water?
Solid iodine dissolved in ethanol (an alcohol)
How does a chemical formula represent a solute and solvent?
It specifies the solute by using its chemical formula and shows the solvent in parenthesis ex NH3(aq)
What would be the solute and solvent in this chemical formula? NH3(aq)
Ammonia gas (solute) dissolve in water (solvent)
What are the 2 ways that compounds can be classified as?
Electrolytes or nonelectrolytes
When are compounds electrolytes?
When their aqueous solutions conduct electricity
When are compounds nonelectrolytes?
If their aqueous solutions do not conduct electricity
How can the conductivity of a solution be calculated?
With a conductivity apparatus or an ohmmeter. It also shows if the solution is an electrolyte or nonelectrolyte
What type of solutions are usually electrolytes?
Highly soluble ionic compounds, including ionic hydroxides
What types of compounds are usually nonelectrolytes?
Most molecular compounds such as ethanol, with the exception of acids
Do acids conduct electricity?
Acids are molecular compounds but when dissolved in water they are conductive
What kind of solutions do ionic and molecular compounds form?
Neutral solution
What happens when a molecular compound is dissolved in water?
It creates a nonelectrolyte solution because the particles disperse electrically neutral particles through the solution. So it does not conduct electricity
What happens when ionic solutions are dissolved in water?
When the ionic compound dissolves, it dissociates into individual aqueous ions. The positive ions are surrounded by the negative ends of polar water molecules and vice versa.
What is dissociation?
The separation of ions that occur when an ionic compound dissolves in water
What is responsible for the properties of basic solutions?
Hydroxide ions
Why are Hydroxide ions responsible for properties of bases?
Because ionic hydroxides are compounds that dissociate into individual positive ions and negative hydroxide ions in a solution
When do the properties of acids appear?
When compounds containing hydrogen dissolve in water
What is the problem when identifying acids in electrolytes?
They contain ions but, but the compounds that become acids are usually molecular, so they are only seen as neutral at first. So they ionize into positive hydrogen ions and negative ions when dissolved in water
What is ionization?
The process by which a neutral atom or molecule is converted into an ion
What does endothermic mean?
Absorbs energy from it surrounding
What does exothermic mean?
Release energy to the surrounding
What type of reaction uses energy?
Reactions that break bonds
What type of reactions release energy?
Reactions that form new bonds
When dissolving an ionic into water will energy be released or absorbed and why?
Energy will be absorbed because it is breaking the bonds between the ionic compound. energy is also required to overcome the intermolecular forces among water molecules. At the same time energy is released because new bonds between the individual ions and polar water molecules form
What are strong acids?
Acids that are extremely good conductors ex sulfuric acid, nitric acid, and hydrochloric acid
What do molecules do when dissolved into water?
Disperse into individual molecules
What do ionic compounds do when dissolved into water?
Dissociate into individual ions
What do bases (ionic hydroxides) do when dissolved into water?
Dissociate into positive ions and hydroxide ions
What do acids do when dissolved into water?
Ionize to form hydrogen ions and anions
What is concentration?
A ratio that compares the quantity of solute to the quantity of the solution
When do chemists describe a solution as dilute?
When it has a relatively small quantity of solute per unit volume of solution
What is a concentrated solution?
A solution that has a relatively large quantity of solute per unit volume of solution
What is the formula for concentration?
C = Vsolute/Vsolution x 100
What would a concentration mean if it said “by volume”?
That means that the amount concentrated is per 100 ml
What would a concentration mean if it said “Weight by volume” or % W/V?
It means the weight in grams per 100 mL is the concentration
What is the formula for weight by volume concentration?
C = Msolute/Vsolution x 100
What is the formula for weight by weight concentration?
C = Msolute/Msolution x 100
What is the ratio for ppm?
1 : 10^6
What type of concentration is ppm, ppb, and ppt measured in? and what is the formula?
Weight by weight
Msolute(g)/MSolution(g) x 10^6
What is amount concentration?
The chemical amount of solute dissolved in one litre of a solution
What is the formula for amount concentration?
amount concentration = chemical amount of solute (in moles)/volume of solution (in litres) or c = n/v
What is an example of preparing a solution from solid solute?
Ice tea crystals in water
What is an example of preparing a solution by dilution?
Tea in water
What are standard solutions?
A solution with a concentration that is known with considerable certainty
What is a stock solution?
An initial usually concentrated, solutions from which pieces are taken by dilution
What would be considered a dilute solution?
A solution with a concentration less than 0.1 mol/L
What would be considered a concentrated solution?
A solution with a concentration of 1 mol/L
What is the formula used to calculate new concentrations after dilution?
ViCi = VfCf
What is a saturated solution?
A solution in which no more solute will dissolve at a specified temperature
What is solubility?
The concentration of a saturated solution
When do solids usually have higher solubility in water?/
At higher tempertaures
When do gases have higher solubility in water?
At lower temperatures and higher pressures
What does it mean for a liquid to be immiscible?
A liquid does not dissolve in water and forms a layer on top
How do polar liquids dissolve in water?
They increase in solubility with higher temperature
What is a liquid that is miscible?
Liquids that dissolve in water in any proportion
How do elements dissolve in water?
Elements usually have low solubility. But, halogens and oxygen dissolve in water to a tiny extent
What is a dynamic equilibrium?
When two opposing processes occur at the same rate
