FINAL

Question 1

Water is a universal solvent. What does this mean?

Answer 1

It will dissolve just about anything over time.

Question 2

Water is less dense in its frozen form than in its liquid form. This is extremely rare. Why is this so special?

Answer 2

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.

Question 3

Water has a high specific heat. What does this mean?

Answer 3

Specific heat is the amount of heat it takes to raise the temperature of 1 gram 1 degree celsius

Question 4

What causes the hexagonal shape of snowflakes?

Answer 4

This is the shape hydrogen bonds form when water molecules join together in a solid form

Question 5

Define homogenous

Answer 5

uniform, of the same kind, alike

Question 6

Define solution

Answer 6

homogenous mixture of molecules from two or more substances

Question 7

Define solvent

Answer 7

present in larger amount

Question 8

Define solute

Answer 8

component dissolved in to solvent

Question 9

What does it mean when a solution is called saturated?

Answer 9

It has reached the maximum amount of solute that can be dissolved.

Question 10

What does it mean when a substance is called insoluble?

Answer 10

It cannot be dissolved

Question 11

Why do water and oil not mix?

Answer 11

Water is polar. Oil is non-polar. Polar cannot dissolve non-polar and non-polar cannot dissolve polar. Remember, like dissolves like

Question 12

Define solubility

Answer 12

the ability of a solute to dissolve in a solvent

Question 13

Define electrolyte

Answer 13

The spring 2015 EU film…or water solutions that carry an electric current (solutions of ionic substances)

Question 14

True or false: adding a pinch of salt to water will increase the boiling point of the water

Answer 14

True, but only by about 0.0037 degrees celsius

Question 15

How does salt keep water from freezing at normal freezing temperatures

Answer 15

It introduces solute particles, which get in the way preventing the water molecules from bonding into a solid crystal form.

Question 16

True or false: Ice is practically pure water.

Answer 16

True: Salt tends to be excluded from ice as salt water freezes

Question 17

What are the 4 properties of acids?

Answer 17

• sour taste
• change color of certain materials (litmus paper turns red)
• react with active metals to release Hydrogen
• neutralize bases (forming water and salt)

Question 18

What are the 4 properties of bases?

Answer 18

• bitter taste
• reverse color changes caused by acids (litmus paper turns blue)
• slippery on skin
• neutralize acids

Question 19

Do acids donate or accept protons when dissolved in water?

Answer 19

donate

Question 20

Do bases donate or accept protons when dissolved in water?

Answer 20

accept

Question 21

Define neutralization

Answer 21

The result of mixing acids and bases together

Question 22

What is hard water?

Answer 22

water with high mineral content (makes it hard for soap to lather)

Question 23

What does PPM stand for?

Answer 23

parts per million

Question 24

T or F: A solution is a heterogeneous mixture of two or more substances.

Answer 24

FALSE: homogenous

Question 25

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.

Answer 25

FALSE

Question 26

T or F: Highway departments spread salt on icy roads because the solution process generates heat, which melts the ice.

Answer 26

FALSE: It is the solute particles that get in the way of the bonding process that prevents freezing, not heat

Question 27

T or F: A solution with a pH of 2 is twice as acidic as a solution with a PH of 1

Answer 27

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

Question 28

What are organic compounds?

Answer 28

Compounds that have carbon as the primary element

Question 29

Define hydrocarbon

Answer 29

any organic compound containing only carbon and hydrogen

Question 30

What are alkanes, alkenes, and alkynes?

Answer 30

Alkanes have only single carbon bonds; alkenes have at least one double bond; and alkynes have at least one triple bond.

Question 31

Out of alkanes, alkenes, and alkynes, only one of the three can be saturated. Which one?

Answer 31

alkanes

Question 32

What are isomers?

Answer 32

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.

Question 33

T or F: Isotopes with an even number of both protons and neutrons are generally stable.

Answer 33

TRUE

Question 34

T or F: A radioactive decay reaction produces a simpler, more stable nucleus.

Answer 34

TRUE

Question 35

T or F: An alpha particle is really a high-energy electron ejected from the nucleus.

Answer 35

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.

Question 36

What type of radiation is really the nucleus of a helium atom?

Answer 36

alpha

Question 37

What type of radiation can easily pass through a human?

Answer 37

gamma

Question 38

What type of radiation ionizes atoms and molecules?

Answer 38

All types of radiation do this

Question 39

T or F: When an isotope releases gamma radiation the atomic number increases by one and the mass number remains the same

Answer 39

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

Question 40

What is the difference between chemical reactions and nuclear reactions?

Answer 40

Chemical reactions involve electrons. Nuclear reactions actually change the nucleus of atoms.

Question 41

Give the number of protons in the nucleus of the following isotope: Potassium-40.

Answer 41

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).

Question 42

Give the number of neutrons in the nucleus of the following isotope: Neon-24.

Answer 42

14

Question 43

T or F: The protons in a nucleus stay together due to the gravitational force

Answer 43

FALSE: The protons in a nucleus stay together due to the nuclear force

Question 44

T or F: The threshold model proposes that under a certain level, your body can repair the damage produced by radiation.

Answer 44

TRUE

Question 45

A measure of radiation that takes into account the possible biological damage produced by different types of radiation is called what?

Answer 45

rem

Question 46

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.

Answer 46

FALSE

Question 47

Isotope A has a half-life measured in minutes, whereas isotope B has a half-life of millions of years. Which is more radioactive?

Answer 47

A

Question 48

The radioactive isotope Z has a half-life of 12 hours. After 2 days, the fraction of the original amount remaining is...

Answer 48

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

Question 49

What are three basic requirements for a fusion reaction?

Answer 49

- dense concentration of hydrogen nuclei - confinement at 10 atmospheres pressure for at least one second - temperature on the border of 100 million C