Unit Test Flashcards
Why do we study chemistry?
- Chem. affects all aspects of life and most natural events.
- Chem. helps explain natural world.
- Studying chem. makes you an informed citizen.
- Connects inanimate world (physics) to the living world (biology)
What is chemistry?
The study of composition (the makeup), structure, and properties of matter and the changes matter undergoes during chemical reactions.
What is matter?
Anything that has mass and takes up space.
What are some examples of matter?
A person, air, blood, a pencil, etc.
What are some examples of things that aren’t matter?
Heat, light, energy, etc.
What are the states of matter?
Solid, liquid, gas, (also plasma)
What measurement system is used in Science?
Metric system
Whats the base unit for mass?
gram (g)
Whats the base unit for volume?
Liter (l)
Whats the base unit for length?
Meter (m)
How do you change a metric system unit?
Multiply or divide by 10.
What is density?
The substance’s mass per unit of volume. The symbol most often used for density is ρ.
How do you calculate Density (g/Ml)?
Density (g/Ml) = mass (g) / volume (Ml)
hint: you can use triangle with mass on top.
What things describe chemisty?
Time, Energy, Temperature, Mole
What is time?
Duration of a process (seconds (s))
What is energy?
Capacity to do work. (Joule (J) or Calories (cal))
What is temperature?
Measure of kinetic energy in particles. (Celcius 0c or Kelvin 273k)
What is mole?
Substance that contains 6.02 * 10^23 particles. (mol)
The quantity amount of substance is a measure of how many atoms or molecules there are. It doesn’t define weight or mass. It’s just a number.
What is the scientific method?
A logical systematic approach to the solution of a scientific problem.
What are the steps of the scientific method?
- Observation of nature (problem)
- Form a hypothesis ( a proposed explanation)
- Experiment and collection of Observations (IV, DV, constants, control)
- Writing conclusion (Summary of results explained)
- Developing theory (Well tested with Repeated trials for broad observations)
- Scientific law (More experiments leading to description of relationships without explanation)
What are the 2 relationships?
Direct and indirect
Whats a direct relationship?
The values increase together
Whats the inverse relationship?
The values negate each other.
What is the independent variable?
Variable changed
Whats the dependent variable?
Variable measured
Whats the controls (constants)?
Things that stay the same in the experiment.
Whats the control group (control)?
The normal IV/ standard not effected by IV
What is the periodic table?
A list of all known elements.
How is the periodic table organized?
Its organized by increasing atomic number.
What are the 3 types of elements on the periodic table?
Metals, Non-metals, and Metalloids.
What is on the left side of the periodic table?
The metals with the greatest metallic properties.
What is on the right side of the periodic table?
The elements with the least metallic properties (Non-metals)
What are the elements in the middle of the periodic table?
Transition elements (properties change from metals to non-metals)
What are metalloids and where are they?
Metalloids are a small group of elements that zigzag between the metals and nonmetals. They have both metallic and nonmetallic propertices.
What are the vertical columns on the periodic table called?
groups or families
What are the horizontal rows on the periodic table called?
periods
If two elements are in the same group or family, what do they have in common?
They have the same number of valence electrons (what determines the elements chemical properties including reactivity)
Where are the valence electrons on the atom?
They are on the outer layer of the atom.
How many groups or families are there?
18
What makes hydrogen special?
It doesn’t belong in any groups, its very reactive, colorless, odorless, and only has one valence electron.
What is group 1?
Alkali metals (extremely reactive, shiny, silver, low density, and soft)
What is group 2?
Alkaline - earth metals (Slightly less reactive, silver, slightly more dense)
What are groups 3-12?
Transition metals (moderate range or reactivity, wide range of properties, usually shiny, good conductors of heat and electricity). Have 1-2 valence electrons.
What and where are Lanthanides and Actinides?
Located at the bottom, these are also transition metals. Lanathanides are shiny and reactive. Actinides are radioactive and unstable.
What is group 13?
Boron (Reactive and have 3 valence electrons (group num - 10))
What is group 14?
Carbon (have varied reactivity)
What is group 15?
Nitrogen group (varied reactivity)
What is group 16?
Oxygen group (reactive)
What is group 17?
Halogens ( all non metal, very reactive, poor conductors, form salts with metals)
What is group 18?
Noble gases (all non metal, unreactive, colorless, odorless)
How many valence electrons does Helium have?
2
Whats the metalloid sequence?
Starts at boron then goes two going down one three times.
What does chemistry describe?
How matters changes
What’s an example of a physical change?
Ice melting
What’s an example of a chemical change?
Iron turning to rust
What is a physical property?
A property you can measure with tools or your senses.
What does malleable mean?
Property meaning it can be bent into a shape without breaking.
What does brittle mean?
The opposite of malleable. Brittle materials like glass break instead of bending.
What does ductile mean?
Property meaning it can be stretched into a thin wire without breaking.
What is physical change?
A change that occurs when there is a change in the physical properties of matter. (can be reversed without changing the chemical identity of a substance)
What is volume?
A physical property of matter.
What must happen in order for it not to be classified as a physical change?
It must become a different compound.
What is a chemical change?
A chemical reaction occurs and Atoms are rearranged to make a new substance. Energy is either given off or absorbed.
What is a chemical property?
A property that can be observed when a substance is transformed into a different substance.
What is a chemical reaction?
Any process in which one substance changes into a different substance.`
What is reactivity?
The ability of a substance to undergo a chemical change and become rearranged into a different substance.
What are some signs of a chemical change?
Color change, bubble formation, odor change, precipitate formation, energy change
What does precipitate describe?
A solid that forms from two liquids as a result of a chemical change.
What are intermolecular forces?
The forces that hold particles together in solids and liquids.
resolution
the smallest quantity that can be measured or displayed
Accuracy
a term that describes how close a measurement is to the true value
Precision
term that describes how close measured values are to each other
Scientific Notation
a method of writing numbers as a base, times a power of 10
Mantissa
a decimal number that multiplies the power of 10 in scientific notation
Exponent
the power of 10 for a number written in scientific notation, such as the 2 in the number 5 x 102 = 500
Rates
ratios that can be used as they are given or inverted.
Dimensional analysis
technique of using conversion factors to convert between units
Atomic mass unit (amu)
a mass unit equal to 1.66 x 10–24 g or 1.661 x 10–27 kg
Atomic mass
the mass of an atom’s protons and neutrons expressed in atomic mass units (amu) on the periodic table; on the periodic table, calculated as a weighted average that reflects isotope abundance
Avogadro’s number
the number of atoms contained in one mole, 6.02 x 1023
Molar mass
the mass of one mole of a substance; the term formula mass is used for ionic substances and molecular mass for covalent substances
What had happened if a substance with a different chemical formula is formed?
A chemical change
A counting
Exact number
A measurement
Can’t have an exact answer (mass, length, time)
What are the parts of the Periodic table element?
Atomic number, Element symbol, Element Name, and Atomic Weight
What are the diatomic elements and why are they called diatomic?
Hint: Have no fear of Ice Cold Bear or BrINClHOF
The 7 diatomic elements are hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). We call them diatomic elements because the atoms appear in pairs.
What are the prefixes of the metric system?
Hint: King Henry Died Drinling Chocoalte Milk
Kilo, Hecto, Deca, Base, Deci, Centi, Milli
What is Density?
the degree of compactness of a substance.
D (g/Ml) = mass (g) / volume (Ml)
What is the unit for Mass?
gram (g)
What is the unit for Volume?
Liter (L)
What is the unit for Length?
Meter (m)
How many chemicals make up all elements?
100
Are elements in constant motion?
Yes
What are some physical properties?
mass, density, melting point, boiling point, color, and state of matter
What ate the categories of the Periodic Table?
Alkali Metals, Alkaline Earth Metals, Transition Metals, Nonmetallic, Halogens, Noble Gases, Lanthanides, Actinides
What are three ways elements are organized in the periodic table?
Groups and periods, metallic character, atomic number
