Science Exam 8 - Chemistry

Question 1

What is matter?

Answer 1

Anything that has mass and volume. It is made of atoms - the smallest unit of an element that still retains that element’s properties.

Question 2

What are atoms made of? - Protons, neutrons, and electrons

Answer 2

Atoms are made up of subatomic particles - protons, neutrons, and electrons.
Protons (found in the nucleus) and neutrons (found in the nucleus) are quarks, and electrons (found outside the nucleus) are a type of lepton.
Quarks and leptons are elementary particles.
Protons have a positive charge.
Neutrons have a neutral charge.
Electrons have a negative charge.

Question 3

Chemical Properties

Answer 3

The ability for a substance to react with another to form a new substance (ex. Flammability, toxicity, combustion)

Question 4

Physical Properties

Answer 4

Characteristics that can be observed and/or measured (ex. Color, malleability, solubility, states of matter, freezing point)

Question 5

Quantitative & Qualitative Data

Answer 5

Quantitative data - measured, explained with numbers

Qualitative properties - observed, explained with words

Question 6

Physical & Chemical Changes

Answer 6

Matter can be altered and transformed by what we call physical and chemical changes
Physical changes: alter matter but do not change its chemical identity
Chemical changes: one or more new substances are formed - chemical identity is changed

Question 7

Density

Answer 7

• Density is a physical property and provides us with qualitative data
• An object’s mass for every unit volume
• Dictates whether an object will sink or float depending on the fluid’s density
  Something with a high/big density will sink; something with a low/small density will float

D = mass/volume

Question 8

Kinetic Molecular Theory

Answer 8

The Kinetic Molecular Theory (KMT) helps explain the different states of matter.
The KMT states: matter is made up of particles that are constantly moving; they move because they have kinetic energy
- Heat is a form of energy. When things have more energy (are heated), particles move faster and get farther apart

Question 9

The 4 States of Matter

Answer 9

Solid, liquid, gas, and plasma

• Plasma has different properties so they can be considered apart from the other 3 (ex. Sun, neon lights, lightning)
• Solids have the least amount of energy; particles are close to each other and vibrate
• Liquids have more energy than solids but less energy than gas; particles have some space between each other and slip and slide
• Gases have the most amount of energy; particles have lots of space and move fast and in straight lines past each other

Question 10

Transformation of States

Answer 10

When changing from one state to another, particles either gain or lose energy, and therefore, the particles speed up or slow down.
- It takes a while for all the particles to reach the same temperature

Solid - Liquid: Melting
Liquid - Solid: Freezing
Solid - Gas: Sublimation
Gas - Solid: Deposition
Liquid - Gas: Vaporization
Gas - Liquid: Condensation

Question 11

Atomic Structure

Answer 11

• The nucleus is made up of protons and neutrons
• Protons and neutrons are made up of quarks
• Electrons surround the nucleus in energy shells
• Electrons are a type of lepton
• Atomic number: number of protons or electrons
  In neutral atom, # of protons = # of electrons
• Atomic mass = # of protons + # of neutrons
  # of neutrons = rounded atomic mass - # of protons

Question 12

Periodic Table

Answer 12

• Rows in the periodic table are called periods - this tells us the number of electron shells an atom has
• Columns in the periodic table are called groups or families - this tells us the number of electrons in the outermost shell

Question 13

How to Draw Bohr Diagram

Answer 13

Draw the nucleus with the atomic symbol inside.
Atomic number = # protons = # electrons (in a neutral atom)
Period = number of shells
Group/family = electrons in outermost shell

Question 14

Shell Rules

Answer 14

1st = max 2 electrons
2nd + 3rd = max 8 electrons
4th + 5th = max 18 electrons

Question 15

Elements vs. Compounds vs. Mixtures

Answer 15

Element: a substance that is made up of only one type of atom
Compound: a substance that is made up of more than one type of atom bonded together (chemical)
Mixture: a combination of two or more elements, or compounds which have not reacted to bond together; each part in the mixture retains its own properties (physical)