FINAL Flashcards
Water is a universal solvent. What does this mean?
It will dissolve just about anything over time.
Water is less dense in its frozen form than in its liquid form. This is extremely rare. Why is this so special?
If water were more dense when frozen, ice would sink rather than float. Because it is less dense, it allows solid ice to float while fish survive underneath. If ice were more dense, it would sink to the bottom and then more ice would form on top and then sink again until the entire lake would be frozen from top to bottom. Now, imagine the disastrous effect that could have.
Water has a high specific heat. What does this mean?
Specific heat is the amount of heat it takes to raise the temperature of 1 gram 1 degree celsius
What causes the hexagonal shape of snowflakes?
This is the shape hydrogen bonds form when water molecules join together in a solid form
Define homogenous
uniform, of the same kind, alike
Define solution
homogenous mixture of molecules from two or more substances
Define solvent
present in larger amount
Define solute
component dissolved in to solvent
What does it mean when a solution is called saturated?
It has reached the maximum amount of solute that can be dissolved.
What does it mean when a substance is called insoluble?
It cannot be dissolved
Why do water and oil not mix?
Water is polar. Oil is non-polar. Polar cannot dissolve non-polar and non-polar cannot dissolve polar. Remember, like dissolves like
Define solubility
the ability of a solute to dissolve in a solvent
Define electrolyte
The spring 2015 EU film…or water solutions that carry an electric current (solutions of ionic substances)
True or false: adding a pinch of salt to water will increase the boiling point of the water
True, but only by about 0.0037 degrees celsius
How does salt keep water from freezing at normal freezing temperatures
It introduces solute particles, which get in the way preventing the water molecules from bonding into a solid crystal form.
True or false: Ice is practically pure water.
True: Salt tends to be excluded from ice as salt water freezes
What are the 4 properties of acids?
- sour taste
- change color of certain materials (litmus paper turns red)
- react with active metals to release Hydrogen
- neutralize bases (forming water and salt)
What are the 4 properties of bases?
- bitter taste
- reverse color changes caused by acids (litmus paper turns blue)
- slippery on skin
- neutralize acids
Do acids donate or accept protons when dissolved in water?
donate
Do bases donate or accept protons when dissolved in water?
accept
Define neutralization
The result of mixing acids and bases together
What is hard water?
water with high mineral content (makes it hard for soap to lather)
What does PPM stand for?
parts per million
T or F: A solution is a heterogeneous mixture of two or more substances.
FALSE: homogenous
T or F: Cooks add a pinch of salt to water to increase its boiling point since it is known that solutions boil at a higher temperature than pure water.
FALSE
T or F: Highway departments spread salt on icy roads because the solution process generates heat, which melts the ice.
FALSE: It is the solute particles that get in the way of the bonding process that prevents freezing, not heat
T or F: A solution with a pH of 2 is twice as acidic as a solution with a PH of 1
FALSE: A solution with a pH of 2 is one tenth as acidic as a solution with a pH of 1. As the pH goes up, the solution becomes more basic. As the pH goes down, it becomes more acidic. Every pH number increase is 10 times more basic than the previous number. Every pH number decrease is 10 times more acidic
What are organic compounds?
Compounds that have carbon as the primary element
Define hydrocarbon
any organic compound containing only carbon and hydrogen
What are alkanes, alkenes, and alkynes?
Alkanes have only single carbon bonds; alkenes have at least one double bond; and alkynes have at least one triple bond.
Out of alkanes, alkenes, and alkynes, only one of the three can be saturated. Which one?
alkanes
What are isomers?
Isomers are molecules with the same molecular formula as another molecule, but with a different chemical structure. Isomers contain the same number of atoms of each element, but have different arrangements of their atoms.
T or F: Isotopes with an even number of both protons and neutrons are generally stable.
TRUE
T or F: A radioactive decay reaction produces a simpler, more stable nucleus.
TRUE
T or F: An alpha particle is really a high-energy electron ejected from the nucleus.
FALSE: Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways.
What type of radiation is really the nucleus of a helium atom?
alpha
What type of radiation can easily pass through a human?
gamma
What type of radiation ionizes atoms and molecules?
All types of radiation do this
T or F: When an isotope releases gamma radiation the atomic number increases by one and the mass number remains the same
FALSE: When an isotope releases gamma radiation the atomic number and the mass number both remain the same. This statement is true about beta radiation
What is the difference between chemical reactions and nuclear reactions?
Chemical reactions involve electrons. Nuclear reactions actually change the nucleus of atoms.
Give the number of protons in the nucleus of the following isotope: Potassium-40.
19: The atomic number of potassium is 19, which means that a potassium atom will always have 19 protons. The atom can gain or lose protons, but then it would no longer be potassium. The 40 is the mass number (or the combined number of protons and neutrons), so this also tells us that potassium 40 has 21 neutrons (40-19).
Give the number of neutrons in the nucleus of the following isotope: Neon-24.
14
T or F: The protons in a nucleus stay together due to the gravitational force
FALSE: The protons in a nucleus stay together due to the nuclear force
T or F: The threshold model proposes that under a certain level, your body can repair the damage produced by radiation.
TRUE
A measure of radiation that takes into account the possible biological damage produced by different types of radiation is called what?
rem
T or F: Airline crews receive roughly ten times the background radiation of those of us who spend most of our time on the ground.
FALSE
Isotope A has a half-life measured in minutes, whereas isotope B has a half-life of millions of years. Which is more radioactive?
A
The radioactive isotope Z has a half-life of 12 hours. After 2 days, the fraction of the original amount remaining is…
1/16: Half life is how long it takes for half of something to decay. In this case, the half life is 12 hours, so in 12 hours, you would have 1/2 of the original amount. In 24 hours, you would have 1/4 of the original amount (1/2 of 1/2). In 36 hours, you would have 1/8 of the original amount (1/2 of the remaining 1/4) and in 48 hours, that will again be cut in half giving 1/16 of the original amount
What are three basic requirements for a fusion reaction?
- dense concentration of hydrogen nuclei
- confinement at 10 atmospheres pressure for at least one second
- temperature on the border of 100 million C
