CHM104 - Chemistry for Life Sciences Flashcards
What is Chemistry?
Chemistry is a field of science dealing with how matter & energy interact with each other.
What are the phases of matter?
- Solid phase/state
- Liquid phase/state
- Gaseous phase/state
What is the key characteristic of a Liquid phase?
It has an indefinite shape but fixed volume.
What is the key characteristic of a Solid-phase?
It has a fixed shape & volume.
What is the key characteristic of the Gaseous phase?
It has no fixed shape & volume.
What are the types of mixtures?
- Homogenous mixtures & non-homogenous mixtures
What are Homogenous mixtures/Solutions?
Homogenous mixtures or solutions are mixtures which are uniformly mixed. Example: Sea water.
What are Heterogenous mixtures?
These are the mixtures which are non-uniformly mixed. Example most rocks like Granite (Having Feldspar, quartz & mica).
What are the methods of separation of mixtures?
- Distillation
- Filtration
- Mass Spectrometry
- Chromatography
What is Mass spectrometry?
It is a method of separation of mixtures by the atomic mass.
Quantity, what is it?
It means you can assess the measurable value of a measurement.
What is the Metric system based on?
It’s a system based on decimal points.
What is Acetone (CH3COCH3) used for?
Acetone is an organic compound used to dissolve other solvents.
Instruments to measure Length?
The Metre Rule is used to measure the Length & the standard unit is in Metres (m).
Conversion of Millilitres to Cm3, please?
1mL = 1cm3
What are the instruments to measure Volume?
- Pipette
- Burette
- Graduated cylinder
What is Mass?
Is the amount of matter in an object
What is weight?
It’s the gravitational force acting on an object
What do we use to Reset the weight of the weighing container on a weighing balance?
The Tare button.
What is the mechanism of Heat flow?
Heat flow is such that it flows from an object with high temperature to an object with low temperature.
Formulae for conversion of Temperature from degrees centigrade to Fahrenheit:
Tf = (1.8)Tc + 32
Formulae for conversion of Temperature from degrees Fahrenheit to degrees centigrade:
(Tf - 32) / 1.8 = Tc
Your decimal points in your answers should..?:
Match the decimals you were given in your question. (For addition or subtraction problem)
What does Intravenously means?
The drug delivery method in the body through the veins
Significant figures & calculations:
Take the value with less significant figures from the data given & assign the same to your final answer. Especially in division or multiplication.
What is Matter?
Matter is anything that occupies space and it has mass.
What is an alloy?
An alloy is a solid mixture of two or more substances making a same composition throughout.
What is the difference between an element & a compound?
An element is a pure substance which is made up of one kind of atom,
WHILE:
A Compound is a pure substance which is made of of more than one kind of atom.
What is a solution?
A solution is a mixture with the same composition throughout.
How many elements are there so far? And which ones occur naturally?
There are 118 known elements so far, of which 91 occur naturally.
Mercury in Latin please (Teaser):
Hg (Hydrargyrum)
Key distinguisher between Compounds & Mixtures:
Compounds have fixed compositions in the same percentages by mass.
While Mixtures have varying compositions.
What are the tools to measure volume?
Measuring Cylinder, Pipette & Burette.
What are pure substances?
They are either elements or compounds
What’s an element?
A type of matter which can’t be broken down into two or more pure substances.
What’s a chemical symbol?
A chemical symbol is the chemical representation of a chemical substance in form of letters. Mostly, 1 or 2 letters.
What’s a compound?
A pure substance is made up of more than one element. e.g Water is a compound made of Hydrogen & Oxygen.
What is the comment on Compounds & their compositions?
Compounds have a fixed composition (Same elements in the same percentage by mass)
Are elements & compounds’ characteristics the same?
No. Usually, the elements & compounds characteristics are different. E.g Na, Cl & NaCl
What are some ways to split compounds?
- Electrolysis
- Heating
What is a mixture?
A mixture comprises of 2 or more substances combined in a way that the substance retain their chemical identity.
What comprises a solution?
A solution comprises of a SOLVENT & SOLUTE. Solvent is usually in the largest amount.
In a Solution, what can Solute be?
It can be a liquid, solid or gas.
What is an example of a Solid solution?
Brass - It’s made up of Copper & Zinc.
What is distillation?
Is a method of separating homogenous solid-liquid mixtures by vaporization & condensation of the liquid, leaving behind the residue solute.
What is filtration?
A method to separate heterogeneous mixtures by using a barrier with fine pores like filter paper.
What is chromatography?
It’s a method of separation of a mixture by the use of solubility or extent of adsorption on a solid surface.
What is a Metric system?
Is a measurement system where the units are measured in the powers of ten.
What is temperature?
Temperature is a factor that determines the direction of heat flow.
What are Celsius?
A unit of temperature with a 100 degrees range based on the the freezing & boiling points of water.
What causes the degree of uncertainty in measurements?
The Nature of the instrument & The skill of the operator.
What is a conversion factor?
A ratio, numerically equal to 1 by which a quantity can be converted from one unit to another.
What’s another name for the Conversion factor?
Dimensional analysis
What are Bridge conversions?
They are conversion ratios allowing you to transfer from the English metric system to the Metric system.
What does pulvarize mean?
Making into powder (powderize), by breaking up or making into dust.
What are Intensive properties?
They are the properties that Identify a substance. They are independent of the amount.
What are Extensive properties?
They are the properties that are dependent on the amount.
What other properties (apart from the intensive & extensive) that we can use to identify chemical substances?
- Chemical properties
- Physical properties
What are Chemical properties?
They are the properties observed as a substance takes part in a chemical reaction. e.g Inertdness of Helium, reactiveness of hydrogen.
What are Physical properties?
They are the properties which are observed without even changing the Identity of the chemical substance. e.g: Boiling point & melting point.
What’s the melting point?
The temperature at which the substances change from solid to liquid.
What’s the boiling point?
The temperature at which the substance changes from liquid to gaseous state.
What is density?
Density of a substance is the ratio of mass to volume
How is the volume of irregular solids obtained?
By displacement method of a liquid.
How is the MASS of regular solids obtained?
By direct weighing.
What is Solubility?
is the process by which the Solute dissolves in a solvent.
What type of change is Solubility?
A Physical change/
What’s the chemical formula for Sucrose?
C12H22O11
What is a Saturated solution?
A solution in equilibrium with undissolved solute.
What is an Unsaturated solution?
A solution containing less solute than the equilibrium.
What is a Supersaturated solution?
A solution containing more solute than the amount allowed at equilibrium.
What can Potassium permanganate be used as?
As an antiseptic (Cleaner) to infections
What are cations?
These are positively charged ions
What are anions?
These are negatively charged ions
Why do things colorate? e.g fruits when left in air etc..
Due to oxidation
What can you comment on temperature & oxidation?
Lowering temperature decreases the rate of oxidation.
Denote these:
- Atomic number
- Mass number
Atomic number = Z
Mass Number = A
What is Atomic number?
Atomic number is the number of protons in the nucleus of an atom.
What is Mass number?
The mass number is the summation of the number of protons & number of neutrons in a nucleus of an atom.
What are Isotopes?
These are atoms with the same number of protons but a different number of neutrons. Example: C-12 & C-14.
What techniques can we use to reduce the rate of Oxidation?
- Refrigeration
- Placing an item in water
- Adding vinegar
What is the use of these Chemicals?
- Potassium permanganate
- Antimony
- Glycerol
These are their uses respectively:
- Potassium permanganate - as an antiseptic in cleaning infections & wounds.
- Antinmony - It is used to detect leakage in oil pipes
- Glycerol - It is used to sweeten drinks & as a food thickener.
What’s the remedy for people who can’t sleep?
A glass of lukewarm milk
Which metal can melt at room temperature?
Gallium
What is the use of Sodium Bicarbonate (Baking Soda) for everyday home use?
To absorb odor.
What are Dalton’s atomic theory principles?
- An element is comprised of tiny particles called atoms
- Atoms of a given element have the same chemical properties (atoms of diff…visa versa)
- In a chemical reaction, atoms move from one substance to another, atoms never disappears or changed into an atom of another element
- Compounds are formed when atoms of 2 or more elements are combined (And the relative numbers of each atoms are constant & definite)
What is an atom?
It’s the smallest part of an element that retains the chemical properties of that element.
How did the first discoveries of subatomic particles come by?
It were the Electrons which were discovered by passing electricity to gases at low pressure.
What are electrons?
They are the negatively charged sub-atomic particles which are found outside the nucleus.
What is the unit charge of an electron?
-1
What is the experiment by J.J Thomson that shows that the electrons are negatively charged & are present?
Passing a Cathode Ray in a cathode tube toward a Zinc Sulfide screen will deflect the ray to the positive plate showing that the electrons are negatively charged.
About atoms reacting, what LAW did J.J Dalton Atomic theory cover?
Law of conservation of mass
Law of Constant composition
State the Law of Constant composition:
Compounds always contain the same elements with the same proportions by mass.
About atoms reacting, what LAW did J.J Dalton Atomic theory cover?
Law of conservation of mass
Law of Constant Composition
State the Law of conservation of Mass:
In a normal reaction, there is no detectable change in mass in an ordinary atom.
State the law of multiple proportions, & where does it apply to?
“The masses of one element that combine with a fixed mass of a second element are in a fixed ratio of small numbers”
- It applies when 2 atoms form more than one compound.
Who proposed the first model that electrons are embedded in a positive charge cloud sphere in an atom?
J.J Thomson
What are Alfa particles?
They are helium atoms without their electrons
What’s the nucleus?
It;s the small densely positively charged part at the centre of an atom
Who made the experiments of the atom in discovering that the nucleus is positively charged?
Ernest Rutherford as the alfa particles were deflected by the nucleus of an atom.
What’s the charge of a proton?
+1, and is equal to that mass of a Hydrogen atom.
What’s the Neutron?
It’s the uncharged particle of the nucleus of an atom with a mass slightly greater than that of a proton.
Why is the mass of an atom concentrated at the nucleus?
because the proton & the neutron are there. They are heavier in mass than the electron
What is the atomic number (Z)
It’s the number of protons in an atom
What is the mass number (A)
It’s the total number of protons & neutrons in a nucleus of an atom.
What’s an Isotope?
An atom with the same number of protons but different neutrons. Example: Hydrogen (Light hydrogen = 0 Neutrons, Deuterium = 1 neutron & Tritium = 2 neutrons)
What does a nuclear symbol show us?
It shows a composition of the nucleus of an atom.
Why do we call it the “Relative mass”?
because actual atoms are hard to measure by a balance on themselves, so we use a scale in relation to the mass of Carbon-12 atom.
What is atomic mass/atomic weight?
It’s the AVERAGE mass of an atom measured RELATIVE to that of another element, using the Carbon-12 scale.
What is the Carbon-12 scale?
An atomic mass scale where the mass of Carbon is assigned 12 amu exactly.
How are the relative masses of atoms determined?
By using a Mass Spectrometer
Why do we have to determine the Isotopic abundances of elements?
Because mostly elements don’t just occur as single isotopes, rather more than 1 isotope.
What is the Avogadros Number?
It’s the number of units in a Mole
What does the Avogadros Number represent?
It represents the number of atoms in an element whose mass in grams is numerically equal to the element’s atomic mass.
What are Periods?
They are horizontal rows in the Periodic table
What are groups?
They are the Vertical columns in the periodic table
What are the main group elements?
They are the elements of group 1,2 and 13 to 18.
What are the Transitional elements?
They are the elements which fall between groups 3 to 12. And period 4 to 6.
What are post-transitional elements?
They are the elements in groups 13 to 15.
What are alkali metals?
They are the elements in Group 1 of the periodic table.
What are alkaline earth metals?
They are elements in group 2
What are Halogens?
They are the elements in Group 17
What are Noble gases?
They are the elements in Group 18
What can you comment on the elements being in the same group?
They usually have the same chemical properties.
What’s the formal definition of a periodic table?
It’s a table showing the arrangement of elements in an increasing atomic number, in such a way that the elements of the same chemical properties fall in the same group.
What are metals?
Substances with characters of malleability, luster, & high electrical conductivity.
What are metalloids?
They are elements which have characters of both metals & non-metals.
What elements do exist alone mostly?
Inert gases
What does the combination of elements create?
Molecules & ions
What are molecules?
A combination of atoms combined covalent to form compounds.
What forces hold the molecules?
Covalent forces
What’s a molecular formula?
A chemical formula showing the number of atoms in each element, discretely. The number of atoms are written as subscript below each chemical symbol.
What’s structural formula?
A chemical formula showing structure of bonded atoms in a molecule.
What is a condensed structural formula?
It’s the chemical formula showing the functional group of that chemical. e.g CH3C00H - Acetic acid
What are ions?
They are the charged atoms when the atom looses or gains electrons
What kind of bond holds the Polyatomic ions?
Covalent bonds
What’s an ionic compound?
A compound formed by both Cations & Anions. e.g NaCl
What are ionic bonds?
Strong electrostatic forces holding together cations & anions in an ionic bond.
Why do Ionic compounds have high melting points?
Because the energy required to separate the cations in these ionic bonds is very huge
Why can we call NaCl an electrolyte, when we call Sugar a Non-electrolyte?
Because once in the water, the Solution of NaCl conducts electricity while that of Sugar doesn’t.
What is the principle of Electric Neutrality?
It states that in any compound, the total positive charge must equal to the total negative charge
Why are noble gases unreactive?
Because they are so Stable.
Which metals do not follow the noble gases stability structure?
The Transitional & post-transitional metals
What are the common polyatomic cations?
NH4+ (Ammonium) & Hg2+ (Mercury I)
What’s the rule for naming monoatomic cations?
By taking the name of the metal. And the anion has an -ide suffix.
How are the names of the Transition Metals like?
They must have roman numeral to indicate specifically which of them is bein talked about
What are binary molecular compounds?
They are compounds formed by 2 non-metals
What are acids?
They are binary molecular compounds having hydrogen which ionize in water to release H+ ions.
Are acids called so when in gaseous form?
No, only when they are in Water.
Oxoacids what are they?
They are acids with oxygen in addition to Hydrogen atoms.
What are oxoanions?
Are polyatomic ions composed of an element, typically a nonmetal, bonded to one or more oxygen atoms. E.g NO3 (Nitrate)
What are isobars?
Are the nuclei with the same mass number but different atomic numbers.
What are Quantum numbers?
They are numbers used to describe the ENERGY LEVELS available to ELECTRONS in atoms.
What are the WAVE FUNCTIONS of Certain QUANTUM NUMBERS associated with?
An electron
What can the expression of the WAVE FUNCTION in these electrons help us know?
- The ENERGY of the orbital
- The SHAPE of the orbital
- The ORIENTATION in space of the orbital
How many QUANTUM NUMBERS does an Electron have?
4 of them. (n, l, ml & ms)
What is the FIRST QUANTUM NUMBER?
It’s the PRINCIPAL ENERGY LEVEL of an atom. It is denoted by a small “n”
What is special between HYDROGEN & the Principal energy level?
The Energy level depends only on “n”
What does the bigger value of “n” means?
It means that the ENERGY OF THE ELECTRON is increasing, and it is found further from the NUCLEUS.
What’s a Sub-level?
A sub-division of the first energy level, n
What does the SECOND QUANTUM NUMBER, l give us?
It gives us the SHAPE of the cloud of electrons.
What does LARGER VALUES of l denote?
They denote more complex shape of electrons in an atom
What is the THIRD QUANTUM NUMBER, ml?
It’s the quantum number which determines the DIRECTION OF SPIN of the Electron Cloud in Space.
What does the FOURTH QUANTUM Number tell us?
It tells us of the DIRECTION OF THE SPIN.
What are the parallel spins?
The electrons with the same DIRECTION OF SPIN
What are OPPOSITE SPINS?
Are the electrons with the OPPOSITE SPIN DIRECTION
State the PAULI’S EXCLUSION PRINCIPLE:
No 2 electrons in an ATOM can have the SAME 4 Identical QUANTUM NUMBERS.
What are some ways we can represent electrons?
Through QUANTUM Numbers, Orbitals & through electronic configuration & ORBITAL DIAGRAMS to name a few.
What is an ELECTRONIC CONFIGURATION?
An electronic configuration is the way of representing electrons as populations in their respective Sub-levels.
What is the abbreviated electronic configuration?
A notation of denoting electrons by shortening using a Noble gas which corresponds to the amount of number of electrons satisfying it
What are ORBITAL DIAGRAMS?
A way to present electrons by showing ELECTRON SPINS directions as UP & DOWN ARROWS.
State Hund’s RULE:
“When several Orbitals of Equal energy are available, as in a given SUB-LEVEL, electrons enter singly with Parallel Spins”
What are PAIRED electrons in orbitals?
They are the ELECTRONS of OPPOSITE Spins occupying the Orbitals.
What does PARAMAGNETIC mean?
It means showing magnetic attraction due to the presence of UNPAIRED ELECTRONS.
What does DIMAGNETIC mean?
It means showing a REPULSION of a Magnetic FIELD, due to the presence of PAIRED ELECTRONS.
What are Isoelectronic elements?
They are atoms with the same electronic configuration.
Why do metals to the right of Scandium not form ions with noble gas configurations?
because it would require a lot of energy to remove the electrons.
State the Periodic Law:
“The chemical & physical properties of elements are a periodic function of their atomic number”
What is ATOMIC RADIUS?
It’s One half of the closest distance of the nuclei from an ordinary element
What is ATOMIC RADIUS?
It’s half of the closest distance of the nuclei from an ordinary element. (Assumed Elements are connected)
What’s the TREND OF THE ATOMIC RADII in the Periodic TABLE?
- It INCREASES DOWN THE GROUP
- It DECREASES ACROSS THE PERIOD
What is IONIC RADIUS?
It’s the RADIUS assigned to a MONO-ATOMIC atom
What’s the Trend of IONIC RADIUS in the PERIODIC Table?
- It INCREASES DOWN THE GROUP
- It DECREASES ACROSS THE PERIOD
What is IONIZATION ENERGY?
It’s the measure of how diffciulty it is to REMOVE AN ELECTRON FROM A GASEOUS ATOM.
What is IONIZATION ENERGY?
It measures how difficult it is to REMOVE AN ELECTRON FROM A GASEOUS ATOM.
What is the FIRST IONIZATION ENERGY?
It is the ENERGY CHANGE for the removal of the OUTERMOST ELECTRON.
What is the Trend for IONIZATION ENERGY in the PERIODIC Table?
- It INCREASES ACROSS THE PERIOD
-It DECREASES DOWN the GROUP
What is ELECTRONEGATIVITY?
The tendency of an Atom to attract electrons towards itself/its bonds.
What is Density?
it’s the unit mass of substance over equal volume of that substance
What are the applications of density?
- Floating of ship
- Construction of aeroplane
- Filling Balloon with air
- The use of metals & metalloids in various bioprosthetics usages
Why does ship float in water? or Submarine, or aeroplane?
The surface area & volume inside makes it later with it’s mass, that is less denser.
Why do Balloons float in air?
Because the Hydrogen air in it becomes on top of the Balloon, making it to float.
What specifically makes aeroplanes float in air?
- The materials used in construction, & the fuel are all less denser. The materials are metalloids which are less denser
- The air in space within
What’s the difference between ACCURACY & PRECISION?
Accuracy - Means the closeness of the experimental value to the actual value.
Precision - The carryout of experiment/analysis to get closer to accurate value
What’s the difference between ACCURACY & PRECISION?
Accuracy - This means the closeness of the experimental value to the actual value.
Precision - The closeness of the experimented values to themselves & tp the accurate value
What is a PYCNOMETER?
It’s a Lab apparatus to determine density
What’s a TETRAHEDRA?
A figure with 3 triangular faces and a triangular base
What happens as electrons are at an optimum distance & energy?
It forms a MOLECULE State e.g in Hydrogen Molecule
Where does COVALENT BOND Exist?
In the MOLECULES & POLYATOMIC IONS
What’s the FUNDAMENTAL LOGIC BEHIND LEWIS Structure?
By sharing electrons, Non-metals become stable, as they acquire NOBLE GAS STRUCTURE.
What are VALENCE ELECTRONS?
The electrons of the Outermost Principal energy “n”. For the Main Group elements it’s the last digit of the group number.
What is a LEWIS STRUCTURE?
A structure of a molecule or an ion, Showing the bond and the electrons as dots surrounding the atoms.
Why are the VALENCE Electrons only shown in the LEWIS STRUCTURE?
Because they are the one which participate in the Covalent bond
What is an unshared electron pair?
It is a PAIR of electrons belonging to one ATOM. It isn’t involved in a BONDING
What is a lone pair?
It is a pair of electrons that are unbonded and exists in a single atom
What is a SINGLE BOND?
It is a bond consisting of only a SINGLE PAIR of shared electrons
What is a DOUBLE BOND?
It is a bond consisting of TWO PAIRS of shared elctrons
State the OCTET RULE:
Bonded atoms (Except Hydrogen), tend to have share in eight Valence electrons
What’s a Central atom?
An atom at the centre of a MOLECULE, to which one or more electrons are bonded from
What are Terminal atoms?
They are the atoms bonded to the CENTRAL ATOM. They are usually Hydrogen, Oxygen or Halogens
Which atoms usually NEVER form Double BONDS?
Hydrogen & Halogens
What separates REASONANCE STRUCTURES?
A double headed arrow
What is a REASONANCE STRUCTURE/form?
A presentation of a Lewis structure of a molecule, showing the possibilities that the real structure might be one of them
What is the REASONANCE HYBRID FORM?
The presentation of a Resonance structure.
Why is RESONANCE there?
They occur when a Lewis structure fails to describe the real properties of a substance.
Mention an organic Structure with REASONANCE
Benzene
What are ISOMERS?
They are compounds with same formula but different properties
What is the FORMAL CHARGE?
It is a charge that an ATOM will have in a molecule if the BONDING ELECTRONS were equally shared
What are the applications of the FORMAL CHARGE?
It helps us know the CORRECT LEWIS STRUCTURE.
What is the other name given to the Odd electron Species like NO?
Free Radicals
What are FREE RADICALS?
They are the polyatomic ions which don’t OBEY THE LEWIS STRUCTURE, by having a deficiency in the Central atom
What are the EXPANDED OCTETS?
They are the Species of compounds which have more than 8 electrons in their Central atom
What are bond angles?
They are angles between 2 covalent Bonds
What is a linear molecule?
A triatomic molecule with a bond angle of 180 degrees
What’s a BENT MOLECULE?
A triatomic molecule with Bond Angles less than 180 degrees.
What is Molecular Geometry?
The shape of the molecule showing the relative position of atoms
What is Electron PAIR REPULSION?
The principle to predict the Shape of the molecule, where the atoms repel each other as far as possible
What is VSEPR?
It’s the Valence Shell Electron Pair Repulsion Theory
What does the VSEPR model suggest?
That the Valence electron pairs surrounding an atom repel one another and the Orbitals with these shells are oriented far apart from each other
What is an IDEAL GEOMETRY?
It is the Geometry of the molecule assuming the effect of the Unshared electrons was neglected
What are the Bond angles of Molecular geometry?
- Linear = 180
- Trigonal planar = 120
- Tetrahedron = 109.5
- Trigonal bipyramid = 90,120,180
- Octahedron = 90, 180
What is a Polar molecule?
A Covalent Bond molecule with UNSYMETRICAL distributions of electrons, hence forming a +ve & a -ve Pole (Dipole)
What is a Non-Polar molecule?
A Covalent Bond molecule with SYMETRICAL distribution of electrons. Usually has no -ve or +ve Poles.
What type of molecules have Non polar covalent Bonds?
Identical Atoms
What is a DIPOLE MOMENT?
The extent to which the polar molecules orient themselves in an ELECTRIC FIELD
What is a DIPOLE?
State at which a molecule has +ve & -ve poles in its atom
Valence Bond Model
Models of the Electronic Structure of molecules in which electrons are assigned to ORBITALS. Whether Pure or hybridized of Individual atoms
What is a hybridized atomic Orbital?
An orbital is formed by mixing 2 types of Orbitals
What is HYBRIDIZATION?
It’s the mixing of 2 or more Orbitals or structures
What is a Sigma Bond?
A chemical Bond which the Electron density in the Inter-Nuclear axis is High
How is the Electron density along the Bonding axis of a Sigma Bond?
Along the axis, the Electron Density is zero
What is a Pi Bond?
The chemical Bond in which the electron density is concentrated far off the Nuclear axis
