Science

Question 1

Scientific Method

Answer 1

1) state of problem
2) hypothesis
3) observation and experiment
4) interpret the data
5) conclusion

Question 2

Matter

Answer 2

Anything that has mass and takes up space

Conservation of matter states that matter cannot be created or destroyed it simply changes forms

Question 3

Element

Answer 3

Substance that cannot be separated into simpler substances by chemical means

Atom is the smallest unit of an element that still has the properties of that element

Question 4

Atom

Answer 4

Atom is the smallest unit of an element that still has the properties of that element

Proton- positive charge, nucleus, mass is 1AMU

Neutron- neutral charge, nucleus, mass is 1AMU

Electron- negative charge, orbits nucleus, mass is 1/1836th AMU

Question 5

Balanced/Imbalanced Atom

Answer 5

Balanced atom has the same number of protons and electrons

Imbalanced charge is called an ion which can be positive or negative

Ion (small word) - electrons (small particle)

Question 6

Isotope

Answer 6

Each element has a set number of neutrons often the same as its number of protons

If an atom has a different number of neutrons than its normal amount it’s called an isotope

Isotope (big word)- Neutron (bigger particle)

Question 7

Atomic mass

Answer 7

The amount of matter that makes up an atom. You can estimate and Adams atomic mass in AMU’s by simply adding up it’s total number of protons and neutrons

Question 8

Atomic number

Answer 8

Number of protons a particular type of atom has. Atomic number defined the type of element

Change number of electrons you have an ion
Change number of neutrons you have an isotope
Change number of protons you have a different element

Question 9

Radioactive Decay

Answer 9

Most isotopes radioactively decay back into their “normal” forms overtime

The time required for half the Addams of a particular substance to disintegrate is known as that substances half life

Question 10

Carbon 14

Answer 10

And isotope created in the earths atmosphere by cosmic rays. All living things absorb carbon-14. When they die this absorption stops and the organisms existing C14 begins to radioactively decay back into C12

By analyzing me amount of C14 remaining in a dead organism and comparing that quantity to the isotopes known a half life scientist can determine how long ago the organism died
(Rings of a tree)

Question 11

Why can’t carbon-14 be dated more than 50,000 years ago?

Answer 11

50,000 years is how long it takes for all of carbon-14 in a thing to turn into carbon-12

However many other elements have much longer half-lives then C14 and can be used to date nonliving things such as moon rocks which are millions of years old

Question 12

Periodic Table

Answer 12

Atomic Properties- organized by row. Atomic number and mass increase as you move left to right and top to bottom (like reading a book)

Chemical Properties (how they behave)- loosely arranged by column

Question 13

Compound

Answer 13

A substance composed of two or more elements

H2O -water
NaCl- SodiumChloride, table salt

Question 14

Bonds

Answer 14

Within compounds, various atoms making of molecules are held together by bonds

Ionic- A bond in which one atom loses an electron to form a positive ion and the other games and electron to form a negative ion, creating an electrostatic force which holds them together (first child steals ball from second child, second child chases first child)

Covalent- A bond formed when atoms share one or more of their valence electrons (first and second child share ball in tug of war, neither letting go)

Question 15

Chemical Change

Answer 15

Chemical composition of a substance is altered

Question 16

Catalyst

Answer 16

Something that starts a chemical reaction such as a spark

Question 17

Mixture

Answer 17

Material that can be separated by physical means into two or more substances

Solution: homogenous mixture in which one substance has dissolved into the other(s)- i.e. Salt water, salt evenly distributed in water

Suspension: A system in which small particles are kept dispersed by agitation or molecular motion in the surrounding medium-i.e churning makes muddy water, but churning stops and mud separates from water

Question 18

Physical Change

Answer 18

A change from one state to another without a change in chemical composition

States of matter:
Solid (coldest) - cannot be compressed, does not take shape of container
Liquid- cannot be compressed, does take shape of container
Gas- can be compressed, does take shape of container

Temperature and pressure can cause physical change - The more pressure on something the more it wants to go to a solid. The less pressure on something it will go toward a gas

Question 19

Gas Laws

Answer 19

Charles Law- Direct relationship between temperature (up) and volume (up)

Boyle’s Law- inverse relationship between pressure (up) and volume (down)

Question 20

PH- presence of hydrogen in an ion

Answer 20

It affects the propensity to bond with other substances

Measured with litmus test

Acid v alkaline , neutral (7) distilled water
Alkaline (cleansers)- hand soap, ammonium, bleach, lye
Acid (food) - milk, coffee, beer, vinegar, battery acid

Question 21

Newton Law of Gravity

Answer 21

The more massive either or both bodies are the greater the gravity force

The further apart two bodies are, the lesser the gravity force btwn them