Chemistry Flashcards
What is chemistry?
The study of matter and its properties, and how those properties relate to one another.
Everything in the universe is made or composed of different kinds of matter in one of its three states:
liquid, solid, gas.
What is matter defined by?
Its properties
—— is the scientific system of writing numbers- very big or very small- easily.
Scientific notation
Scientific notation is composed of three parts:
- a mathematical sign (+ or -)
- significand
- exponential/ logarithm
What is the significand?
The base value of the number or the value of the number when all the values of ten are removed.
What is the exponential?
A multiplier of significand in powers of ten.
Difference between a positive exponential and a negative exponential?
Positive multiplies the significand by factors of ten.
Negative multiplies the significand by factors of one tenth (0.1).
HINT for exponents representing exponentials:
The exponent shows how many 0s are present in the value. For negative exponents, the 0 before the decimal counts as one of the zeros present in the value.
EX: 10^6 = 1,000,000
10^ -6 = 0.000001
Consider the following:
-9.0462 X 10^5 =
What is the significand and what is the final answer?
The significand is -9.0462
The final answer is -904,620
Consider the following:
4.7 x 10^-3
What is the final value?
0.0047
Exponent hint when multiplying the significand by a positive vs a negative exponent:
- exponent shows how many places to move the decimal to the left
+ exponent show how many places to move the decimal the the right.
What system measure weight, length, and volume?
Metric system. Standard in health professions
3 basic measurements of the metric system:
-grams (weight)
-liters (volume)
-meters (distance)
Label the prefix and the basic unit of measure in “kilogram”
Prefix: kilo
basic unit of measure: gram
What are prefixes?
Quantifiers of the measurement units.
What prefix represents 10^12, or 1 trillion times
Tera (T)
What prefix represents 10^9; 1 billion times?
Giga (G)
What prefix is for 10^6; 1 million times?
Mega (M)
What prefix is for 10^3; 1 thousand times?
kilo (k)
What prefix if for 10^2; 100 times?
hecto (h)
What prefix is for 10^1; ten times?
Deka (D)
What prefix is for 10^-1; 1 tenth of
deci (c)
What prefix is for 10^-2; 1 hundredth of
centi (c)
What prefix is for 10^-3; 1 thousandth of?
milli (m)
What prefix is for 10^-6; 1 millionth of?
micro (u)
What prefix is 10^-9; 1 billionth of?
nano (n)
What prefix is for 10^-12; 1 trillionth of?
pico (p)
What prefix is for 10^-15; 1 quadrillionth of?
femto (f)
What is a little less than 2 cm in diameter?
A dime
About how many pounds are in a kilogram?
2.2 lbs
A liter is a little more than a —-
quart
Three most common temperature systems:
Fahrenheit, Celsius, Kelvin
Zero degrees F is what?
The freezing point of sea water or heavy brine at sea level
What is the freezing point of pure water at sea level in Fahrenheit?
32 degreesF (0 C) (273K)
What is the boiling point of pure water at sea level in Farenheit?
212 degrees F (100 C) (373K)
What is the normal body temperature in Fahrenheit?
98.6 degrees F (37 C) (310K)
Celsius is sometimes called?
Centigrade: used by the rest of the world and the scientific community.
What temperatures are thought to be the lowest temperature achievable? or “absolute zero” (o)?
-273.15 C ; 0K
What is the basic building block of all molecules?
An atom
Physical structure of an atom?
Nucleus, orbits, and sometimes electron clouds.
Electrons orbit the nucleus at various energy levels called:
shells or orbits (like layers of an onion)
When is an atom considered to be most stable?
When its outermost orbit is full.
What type of atoms tend to have equal numbers of protons and electrons, making them electrically neutral?
“Ground state” atoms
What is an atom called when it is electrically charged?
An ion; is in an ionic state
Words indicating charges of an atom as positive or negative.
Negative : “anion”
Positive: “cation”
The rows of a periodic table are called:
Periods: horizontal.
They have similar physical properties and the same number of shells.
7 periods
The columns in the periodic table are called:
Groups: vertical.
Reacts to other elements in similar ways.
18 groups
What is the periodic table?
A chart of known elements arranged according to their properties; helps to predict charge of an atom or element when it exists as an ion.
How do the groups progress?
IA (+1); IIA (+2); IIIA (+3);
IVA (+4) OR (-4);
VA (-3); VIA (-2); VIIA (-1);
VIII = Noble gases (no charge) remains neutral in all solutions/situations.
The chart also shows how many electrons are likely to be in the outer shells of each by the group.
Rows show how many shells they have.
Groups 3 IIIB through 12 IIB on the periodic chart are what?
Transition metals: not as straightforward to predict because of some exceptions to the rules.
What are two important numbers or properties of atoms that can be obtained from the periodic table?
Atomic number
Atomic mass
What is the atomic number?
The number of protons in the nucleus. Defines an atom as a particular element.
EX: Any element with 11 protons, regardless of neutrons or electrons, is sodium (Na).
Where is the atomic number located?
At the top of each square in the periodic table. (Always a whole number).
What is the atomic mass?
The average mass of each of that element’s isotopes.
What is an isotope?
Different kinds of the same atom that vary in weight due to varying numbers of neutrons (always the same number of protons).
EX: Carbon 12 (^12 C), the most common carbon has 6 protons and 6 neutrons.
The isotope used for carbon dating is Carbon 14 (^14 C), which has 6 protons and 8 neutrons.
What makes up the elements mass?
Protons and neutrons makes up nearly all of the atom’s total mass.
Where can the atomic mass be found?
At the bottom of each of the squares. (Is usually a decimal).
What is usually seen of protons and neutrons with elements found in their most common form?
The number of neutrons and protons is the same.
What is the simplest form of matter that can naturally exist in nature?
An element or an atom.
When elements/atoms exist in combination with other elements, they are called:
Compounds: They combine in whole number ratios.
Chemical equations are made up of two parts:
Reactants: react to produce desired end results or compounds
Products: The end results or compounds
Reactants»_space;> Products
What law states that mass cannot be created or destroyed during a chemical reaction?
The law of conservation of mass. This means that a chemical equation must be balanced on both sides of the equation.
What is an example of equilibrium?
A chemical reaction that proceeds to completion, leaving some reactants without products.
In equilibrium, what is the rate in which reactants are forming products, and products are forming reactants?
The same rate.
A reaction at equilibrium is said to be what?
Reversible.
Through manipulation of the reaction by various mean, shifts in equilibrium reversibility or the rate of the reaction can be controlled. What are the 4 basic ways to increase reaction rate?
increase temperature in the reaction
increase surface area of the reactants
add a catalyst
increase concentrations of the reactants
How does increasing the temperature increase the reaction rate?
Increase in temperature = particles have greater kinetic energy.
Moving faster = greater chance of collision at higher energy forces.
When do chemical reactions occur?
Upon contact
How does increasing the surface area increase reaction rate?
Smaller particles of reactants allows for greater chances of contact.
How does a catalyst increase reaction rate?
Reduces activation energy/ amount of energy necessary for a reaction to occur.
What happens to a catalyst after a reaction?
It is not fully used up and can be collected at completion.
Examples of common catalysts:
metals and proteins (enzymes)
How does increasing the concentration of the reactants increase reaction rate?
More of a particle will add to the likelihood of contact/collision between reactions, producing more products.
—— is a homogenous mixture of two or more substances.
Solution
What makes up a solution?
Solute and solvent
——- is the part/parts of a solution that is being dissolved.
Solute
—— is the part of a solution that is doing the dissolving
Solvent
solutions can be made up of what matter forms?
liquid in a liquid
solid in a liquid
solid in a solid
4 types of solutions:
Compounds
Alloys
Amalgams
Emulsions
—– is a type of solution made of mixtures of different elements to create a single matter
Compounds
—— is a type of solutions that is solid and made up of metals to make a new one such as bronze (copper and tin), or steel (iron and carbon)
Alloys
Alloys may contain the following metals: (3)
Tungsten, chromium, and manganese
—– is a solution that is a specific type of allow in which a metal is dissolved in mercury.
Amalgams
—– is a solution type that is a mixture of matter that readily separates such as water and oil
Emulsions
—— is expressed as weight per weight (e.g. grams per grams); weight per volume (e.g. grams per liters); or volume per volume (ml per L)
Concentration
—— ——– is the expression of concentrations as parts per 100 parts.
Percent concentration
EX: mg per 100 mL = mg/100mL =mg/dL
A concentration expression of milliliters (mL) per 100 milliliters (mL) can be written as?
mL/100mL or mL/dl
What is one of the most important concepts in chemistry?
A mole
What is a more sophisticated way to express concentrations than percent?
Molarity, or molar concentration
What is a mole?
6.02 x 10^23 molecules of something. More than a trillion trillions
“Avogadro’s number”
A one molar solution will contain 6.02 x 10^23 representative molecules of a solute in how much of a solvent?
1 liter
How are molar concentrations written?
mol/L
one mole, or 6.02 x 10^23, atoms of an element or compound is equal to what?
The atomic mass of the element/compound in grams = 1 mole
——– is the making or changing of chemical bonds between elements/compounds to create new chemical compounds- resulting in different chemical formulas and different chemical properties.
Chemical reaction.
5 main types of chemical reactions:
Synthesis, decomposition, combustion, single replacement, double replacements.
When a reaction occurs, what is the product generally?
A molecule.
A molecule in a chemical equation may have what after the chemical symbol?
A subscript (opposite of exponent position on the right hand side)
EX: O(2) = oxygen
What type of reaction represents two elements combining to for a product?
Synthesis:
EX: Potassium and chloride combine to make potassium chloride salt
2K+ + 2Cl-»_space; 2KCl (notice the + and the - works to make a whole molecule. The common value of both molecules can be placed as a multiple in front of the whole product)
——- is a type of chemical reaction that is the opposite of synthesis because it breaks a compound into its component parts.
Decomposition:
EX: NaCl»_space;> Na+ + Cl-
(cation and anion)
This type of chemical reaction is self-sustaining, exothermic (creates heat) reaction where oxygen and a fuel compound such as hydrocarbon react.
Combusiontion.
In the combustion of hydrocarbon (gas or oil product), what are the productes?
CO2 and H2O (ALWAYS)
CH + O2 > CO2 + H2O (with stoichiometry to determine quantities of each to balance the equation)
What does the combustion equation of ethane look like?
Ethane = 2C(2)H(6) (g) + 7O(2) (g)
Combustions must react with oxygen. (g) = gas
Start with Carbon.. 2C(2) = 4 carbon available.
We know carbon dioxide makes CO2. How many oxygen is available?
7O(2) = 14 oxygen molecules available.
For every carbon molecule, we need to oxygen molecules. : 4C + 8O: = 4CO(2) (g)
How many oxygen molecules are left? 6O
How many hydrogen molecules are in ethane? 12. 2H(6) = 12H
For H(2)O we end up with 6H(2)O (g)
Type of chemical reaction that involves ionic compounds.
Single replacement
What determine whether or not a reaction will take place in a single replacement reaction?
The reactivity of the metals involved.
A single replacement reaction consists of a more active metal that reacts with what to produce a new compound?
An ionic compound that made up of a less active metal.
What is a good example of a single replacement reaction?
Combining copper (Cu) with aqueous silver nitrate (AgNO(3)).
What will happen when combining copper (Cu) with aqueous silver nitrate (AgNO(3)).
The copper and the nitrogen will switch places.
(aq) stands for aqueous
(s) stands for solid
Cu (s) + 2AgNO(3) (aq)»_space; Cu(NO(3)(2)) (aq) + 2Ag (s)
Copper + silver nitrate yields copper nitrate + silver
Type of reaction that involves two ionic compounds that have “switched partners” where the positive ion from one compound combines with the negative ion of the other compound (and vice-versa).
Double replacement
Good example of a double replacement chemical reaction?
Silver nitrate + potassium chloride
yields silver chloride + potassium nitrate
AgNO(3) + KCl»_space;> AgCl + KNO(3)
—— is the joining of one atom, element, or chemical to another
Chemical bonding.
The type of bonding that occurs is determined by what?
The electrons in the outer shell of the atom.
Two main types of chemical bonds:
ionic and covalent
——- is a type of bond that is an electrostatic attraction between two oppositely charged ion (cation and anion). “Taking and giving”
ionic bond. also known as an “electrostatic bond”
The gain and loss of an electron to make up a neutral charge