Week 1: Introduction To Chemistry Flashcards
What is chemistry?
The study of matter, its chemical and physical properties, and the chemical and physical changes it undergoes.
Define matter.
Anything that has mass and occupies space.
What are the two classifications of matter by composition?
- Pure substances * Mixtures
What is a pure substance?
A substance that has only one component.
What is a mixture?
A combination of two or more pure substances in which each substance retains its own identity, not undergoing a chemical reaction.
Define element.
A pure substance that cannot be changed into a simpler form of matter by any chemical reaction.
Define compound.
A pure substance resulting from the combination of two or more elements in a definite, reproducible way, in a fixed ratio.
What does the periodic table represent?
A tabular arrangement of elements where elements in a particular group share many similarities.
Name the important elements in biological systems.
- C: Carbon * H: Hydrogen * N: Nitrogen * O: Oxygen * P: Phosphorus * S: Sulfur
What is the role of potassium (K) in biological systems?
Responsible for fluid balance.
What is an atom?
The smallest unit of an element that retains the chemical properties of that element.
What is the composition of an atom?
- Nucleus: small, dense, positively charged region containing protons and neutrons * Electrons: negatively charged particles surrounding the nucleus
What is atomic mass unit (amu)?
A unit of measurement for mass of an atom.
What is an isotope?
Atoms of the same element having different masses that contain the same number of protons but different numbers of neutrons.
What is electron configuration?
Describes the arrangement of electrons in atoms and is the primary factor in understanding how atoms join together to form compounds.
Define valence electrons.
Outermost electrons involved in chemical bonding.
What is a chemical bond?
The force of attraction between any two atoms in a compound.
What is a covalent bond?
Attractive force due to the sharing of electrons between atoms.
What is an ionic bond?
Attractive force due to the transfer of one or more electrons from one atom to another.
What are polyatomic ions?
Composed of 2 or more atoms bonded together with an overall positive or negative charge.
What are the types of non-covalent interactions?
- Dispersion forces * Permanent dipolar interactions * Hydrogen bonds * Ionic interactions * Hydrophobic forces
What is solubility?
The maximum amount of solute that dissolves in a given amount of solvent at a specific temperature.
What is the difference between polar and nonpolar molecules?
- Polar molecules: hydrophilic (water-soluble) * Nonpolar molecules: hydrophobic (water-insoluble)
What is the standard unit of mass?
Gram (g).
What is the formula for calculating the mass of a water molecule (H2O)?
2 × 1 Da (hydrogen) + 1 × 16 Da (oxygen) = 18 Da.
What are the common prefixes of units of measurement?
- Mega (M): 10^6 * Kilo (k): 10^3 * Milli (m): 10^-3 * Micro (µ): 10^-6 * Nano (n): 10^-9
True or False: Electronegativity is a measure of the ability of an atom to attract electrons in a chemical bond.
True.
What is the mass of a hydrogen atom in Dalton (Da)?
1 Da
What is the mass of an oxygen atom in Dalton (Da)?
16 Da
What is the total mass of a water (H2O) molecule in Dalton (Da)?
18 Da
What is a mole (mol) defined as?
1 mole of atoms = 6.022 × 10^23 atoms
What is the atomic mass?
The mass of a single atom in Da
What is the molar mass?
The mass of a mole of atoms in grams
What is the molar mass of calcium (Ca)?
40 g/mol
What is molarity (M)?
The number of moles of solute per liter of solution
How much glucose is in a 1 M solution of glucose in water?
180 g glucose in 1 L of water
What is the density of cork?
0.25 g/mL
What is the density of water?
1 g/mL
What is the density of brass?
8.5 g/mL
What is the density of liquid mercury?
13.6 g/mL
Define a chemical reaction.
A chemical substance is converted into one or more different substances by rearranging, removing, replacing, or adding atoms
In a chemical equation, where are reactants written?
On the left of the arrow
In a chemical equation, where are products written?
On the right of the arrow
What is the purpose of balancing a chemical equation?
To ensure the number of atoms for each element is the same on both sides
What is a reversible reaction?
A reaction that can proceed in both the forward and reverse directions
What is equilibrium in a chemical reaction?
The rates for the forward and reverse reactions are equal
What does the equilibrium constant (K_eq) describe?
The relative position of an equilibrium when equilibrium has been reached
What does a small K_eq indicate?
More reactants than products
What does a high K_eq indicate?
More products than reactants
What is a catalyst?
A substance that increases the reaction rate without undergoing any net change
What is the Brønsted-Lowry definition of acids?
Acids are proton (H+) donors
What is the Brønsted-Lowry definition of bases?
Bases are proton (H+) acceptors
What is the ionization of water?
H2O + H2O ⇌ H3O+ + OH-
What is the relationship between [H3O+] and pH?
pH = -log [H3O+]
What does a lower pK_a indicate?
A stronger acid
What is the function of a buffer solution?
To resist pH changes when small amounts of acid or base are added
What are polyprotic substances?
Substances that can donate or accept more than one proton
What defines oxidation in redox reactions?
Loss of electrons
What defines reduction in redox reactions?
Gain of electrons
What is organic chemistry?
The study of carbon-containing compounds
What are hydrocarbons?
Molecules that contain only carbon and hydrogen
What is the structural formula of a linear chain hydrocarbon?
A sequence of carbon atoms connected by single bonds
What is a saturated hydrocarbon?
A hydrocarbon with only single bonds
What is an unsaturated hydrocarbon?
A hydrocarbon containing at least one double or triple bond
What is resonance in chemistry?
The phenomenon where more than one valid Lewis structure can be written for a molecule
What characterizes aromatic compounds?
Compounds that contain the benzene ring or its derivatives
What are functional groups?
Atoms or groups of atoms responsible for the physical and chemical properties of molecules
What is the hydroxyl group?
−OH
What is the structure of alcohols?
An organic molecule with a hydroxyl group
What do thiols contain?
A sulfhydryl group (−SH)
What is the electronegativity of hydrogen and carbon?
Low electronegativity
What is the electronegativity of oxygen and nitrogen?
High electronegativity
What type of bonds do alcohol molecules form?
Hydrogen bonds
What groups do carboxylic acids consist of?
- Carbonyl group
- Hydroxyl group
Are carbonyl groups polar or non-polar?
Polar
Can aldehydes and ketones form hydrogen bonds?
No
Hydrogen bonding in carbonyl compounds involves which molecule?
Water
What functional group do thiols contain?
Sulfhydryl group
What is the bond polarity of the S-H bond compared to the O-H bond?
Less polar
What are the three types of amines based on substitution?
- Primary
- Secondary
- Tertiary
Are amino groups polar or non-polar?
Polar
Do all amines form hydrogen bonds with water?
Yes
What type of acid are carboxylic acids considered?
Weak acids
What is the definition of isomers?
Compounds with the same molecular formula but different structures
What are stereoisomers?
Isomers that have the same order of atoms but differ in spatial arrangement
What are the two types of stereoisomers mentioned?
- Cis and trans isomers
- Enantiomers
What defines enantiomers?
Non-superimposable mirror images
What is a chiral carbon atom?
A carbon atom that has four different groups bonded to it
What is the significance of Thalidomide in relation to isomers?
One isomer is a sedative, while the other is a teratogen
Fill in the blank: Amines are _______ bases.
Weak
What is the structure of a carbonyl group?
C=O
