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- 11. List 4 characteristics of water-Water is a powerful solvent, dissolving most substances involved in living processes.
-It remains a liquid over a wide temperature range.
-It protects cells from rapid temperature changes, because it changes temperatures slowly.
-It expands when it becomes a solid. - 22. On Earth, water is the only substance that can....exist in gas, liquid and solid states in nature
- 33. What would happen if water was Arranged in a line as H-O-Hwater would be a non-polar molecule that sinks as a solid. If water was like this, lakes would freeze solid in winter!
- 44. What results in ice?The fact that water is a bent molecule also makes it harder to "stack" and compress the molecules very close together when cooled. This results in ice having a lower density that liquid water, since it has the same mass but takes up more space
- 55. Why does ice float?it cools down to freeze it begins to expand, taking up more space and thus reducing its density. Since it becomes less dense, it floats.
- 66. What is a result of water having a slightly negative end and a slightly positive end?it can interact with itself and form a highly organized structure.
- 77. What forms within a water molecule as a result of unequal distribution of electrons? a bond a dipole salt an overall (net) ionic chargea dipole
- 88. What substances can be dissolved in water? polar molecules non-polar molecules substances that carry a net electrical charge none of the abovepolar molecules
- 99. How are solutions formed?By dissolving a substance in another, resulting in a uniform distribution
- 1010. When a solution is examined through a powerful microscope, can you observe more than one phase? Is the solution classified as a compound?No, only one phase can be seen because the dissolved particles are evenly dispersed
The solution is not classified as a compound because you can vary the amount of substance added to make the solution. - 1111. If you have two liquids which one is the solvent?The liquid present in the largest amount is considered the solvent and the liquid with the smaller volume is the solute
- 1212. Explain what needs to occur in order for a solution to form (referring to solutes and solvents)The intermolecular forces between solute and solvent particles must be strong enough to compete with those between solute particles and those between solvent particles. As a solution forms, the solvent pulls solute particles apart and surrounds, or solvates, them
- 1313. Depending on how much substance is added to make a solution, you can get one of three types of solutions in order of increasing amount of solute:An unsaturated solution, a saturated solution or a supersaturated solution.
- 1414. What are the most common solutes and solvents?Most solutes are solids and the most common solvent is water although many industrial materials use more exotic and often highly toxic solvents such as benzene or xylene
- 1515. What is the concentration of a solution?It provides information about the strength of the solution. It is the quantity of dissolved substance per unit of volume of solvent in a solution
- 1616. What is the basic formula for concentration?
- 1717. A solution contains 38.2 g of potassium bromide in 78 mL of water. What is its concentration in g per 100 mL of water?
- 1818. Give an analogy to 1 ppm and 1 ppb1 ppm can be represented by 1 drop in a full bathtub, and 1 ppb would be 1 drop in a full swimming pool
- 1919. Calculate the concentration, in ppm, of chlorine ions found in drinking water, if 795 g of chlorine ions are added to 256 000 000 g of water.
- 2020. Calculate the concentration, as % volume, of a solution of vinegar that has 5 mL of pure acetic acid per 100 mL of solution.
- 2121. What is the formula for molarity?
- 2222. What is the molarity of a solution that contains 12.7 g of hydrochloric acid in 250 mL of solution?
- 2323. What is the mass of barium fluoride in 1 L of a 1.4 M solution?
- 2424. How does a solution become more dilute?When more solvent is added to a solution, which changes the concentration (reducing it)
- 2525. The formula to calculate dilution is:
- 2626. A solution of 2.58 M nitric acid is used in order to make a diluted solution. 78 mL of this acid is used in order to make 400 mL of final solution. What is the concentration of the diluted solution?
- 2727. The solubility of a substance can be affected by: (4 things)1. The nature of the substances
For example, ionic compounds and hydrates dissolve in aqueous solutions.
2. The polarity of the substances
For example, polar substances dissolve in polar solvents.
3. The temperature
Some substances only dissolve above certain temperatures.
4. The pressure
Some substances only dissolve when under pressure. - 2828. The rate at which a substance dissolves is affected by: (4 things)1. Particle size
Finely divided substances have more surface area and dissolve more rapidly.
2. Motion
Stirring or shaking brings more solvent into contact with more solute particles, increasing solubility.
3. Temperature
The solubility of most solids increases with temperature.
4. The solubility of gases decreases with temperature. - 2929. A chemical reaction has probably occurred when any of the following are observed:change of colour
heat is released (exothermic)
heat is absorbed (endothermic)
light is produced
a precipitate is formed
a gas is produced (bubbling)
a new odour is detected - 3030. What is a net ionic equation?It includes only the species involved in the chemical reaction. It is an equation that forms a precipitate.
- 3131. What are spectator ions?The ions that are present but do not form a precipitate will remain as ions in the solution
- 3232. What is an acid?A chemical compound which dissolves in water to produce hydrogen ions (H+)
- 3333. List the properties of acidscan be liquid or solid
corrosive
sour taste (vinegar (acetic acid), lemon juice (citric acid))
good conductor of electricity
reacts with many metals (Mg, Zn, K, Na...) to produce hydrogen gas
reacts with carbonates to produce CO2 gas
makes litmus paper become red
makes bromthymol blue turn yellow - 3434. What is a strong acid?If the acid dissociates (or ionizes) strongly (almost completely)
- 3535. What is a base?A chemical compound which dissolves in water to produce hydroxide ions (OH-)
- 3636. What are the properties of bases?can be liquid or solid
has a soapy/slimy feeling
very corrosive, or caustic (they can burn)
has a bitter taste
good conductor of electricity
reacts with a acids
does not react with metals to form hydrogen
makes red litmus paper turn blue
turns initially clear phenolphthalein pink
allows bromthymol blue stay blue - 3737. What is a strong base?If the base is soluble in water (The opposite is a weak base)
- 3838. What is the pH scale?Corresponds to the exponent of the [H+], and measures the strength of the hydrogen ion in the solution.
- 3939. For acids, the pH is ________ and for bases the pH is ________below 7
above 7 - 4040. Find the pH of a solution that has 4.2 x 10-4 M hydrogen ions.Solution
pH = -log[H+]
= -log(4.2 x 10-4 M)
= -(-3.38)
= 3.38 - 4141. What is the pH of a solution containing 10-2 M NaOH?Solution
pOH = -log[OH-]
= -log (10-2 M)
= -(-2)
=2
and pH + pOH = 14
so, pH = 14 – pOH
pH = 14 – 2
=12 - 4242. It is possible to determine the pH of an acid, or a base, using an indicator. What is an indicator?A substance used to detect the presence of certain molecules (e.g. acids) in a solution.
- 4343. What is the most common chemical reaction and what occurs?The reaction of an acid with a base known as a neutralization reaction.
The physical and chemical properties of the base and the acid disappear. H+ reacts with OH- to form water. - 4444. What is the purpose of a titration?To find the concentration of an unknown solution by adding a chemical solution of known concentration
- 4545. What volume of 0.1 M HCl will neutralize 1 L of 0.9 M Ba(OH)2?na = 1 mol
Ma = 0.1 M
Va = ?
nb = 2 mol
Mb = 0.9 M
Vb = 1 L
- 4646. What is kinetic molecular theory used to explain and what does it state?Used to explain properties of solids, liquids and gases
It states that everything is made of tiny particles that are constantly in motion - 4747. State Boyle's Law What is the formula?At any constant temperature, the product of the pressure and the volume of any size of a sample of any gas is a constant.
P1V1=P2V2 - 4848. State Charles' Law What is the formula?At any constant pressure, the volume of any sample of any gas is directly proportional to the temperature.
V1T2 = V2T1 - 4949. What is the formula for Gay-Lussac's law? What is assumed?P1T2 = P2T1
Constant volume is assumed - 5050. State Avogadro's Law What is this equivalent to (in a statement)?Equal volumes of gases under the same conditions of temperature and pressure contain equal numbers of molecules. The particles’ size or mass have no effect since the distances between the particles in a gas is so large.
That volume is directly proportional to number of atoms or molecules. - 5151. ideal gas law formula Universal gas constant equals:PV = nRT
Where
PV/T = constant
R = 8.3145 J/mol•K - 5252. What is an ideal gas?A theoretical gas composed of many randomly moving point particles that do not interact except when they collide elastically. (ie neglecting molecular size and intermolecular attractions)
- 5353. Why do we need ideal gas laws?because gas laws are only ideal for monatomic gases. They do not work well with real gases (e.g. O, Cl) in which molecules attract each other, especially at high pressures when they are close together
- 5454. State Dalton's LawFor a mixture of gases in a container, the total pressure exerted is the sum of the pressures that each gas would exert if it were alone.
- 5555. Dalton's Law:Ptotal = P1 + P2 + P3 + …
Where Ptotal is the total pressure
P1, P2… are the partial pressures of the individual gases - 5656. For Dalton's Law: The total pressure measured is the...Sum of the partial pressure of the collected gas and the partial pressure of the liquid, which is its vapour pressure
- 5757. For vapour pressure, if the liquid is water, as is most often the case, the pressure of the gas collected must be:Ptotal = P(gas) + P(H2O)
or
P(gas) = Ptotal - P(H2O)
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- Fichas sobre Sin título, creado por Alex Obray el 18/03/2016.
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