Chemical and Physical Foundations

Question 1

Units
Physical quantity, base units, symbol

lengyh
mass
time
electric current
temperature
frequency
sound intensity

Answer 1

length–> metre–> m
mass–> kilogram–> kg
time–> Second–> s
electric current–> Ampere–> A
magnetic field–> Tesla–> B
temperature–> Kelvin–> K
frequency–> Hertz–> Hz
sound intensity–> decibel–> dB

Question 2

wehn your equation has a constant (gravitational constant, planck’s constant, etc) this is an indication that you must use ___ units

Answer 2

SI

Question 3

Prefixes
prefix, symbol, order of magnitude

nano
micro
milli
centi
kilo
mega
giga

Answer 3

nano–> n–> 10^-9
micro–> μ–> 10^-6
milli–> m–> 10^-3
centi–> c –> 10^-2
kilo–> k–> 10^3
mega–> M–> 10^6
giga–>G –> 10^9

Question 4

angstrom (Å), unit of length, equal to:

Answer 4

1x10^-10 or 0.1nm (nanometer)

Question 5

to convert from km/h to m/s _______ by 3.6

Answer 5

divide

Question 6

to convert from m/s into km/h ______ by 3.6

Answer 6

multiply

Question 6

The speed of light is

Answer 6

c = fλ relates the speed of light (c), its frequency (f), and its wavelength (λ)

Question 7

for scientific notation, making the coefficient a bigger number means the exponent must get

Answer 7

smaller (or more negative)

Question 8

when adding or subtracting scientific notiation, you want coefficients to have the ___ exponent

for multiplying in scientific notation, we ___ exponents and ___ the coefficients

to divide in scientific notation, we ___ exponents and ___ the coefficients

Answer 8

same

add, multiply

subtract, divide

Question 9

for scientific notation, making the coefficient a smaller number means the exponent must get

Answer 9

bigger (or more positive)

Question 10

how do you round intermediate calculations?

Answer 10

one up and one down

ex: 8.9x11.1=9x11=99=100
then for the next calculation, round down: 100x1.14=114=110

Question 11

with fractions, try to round the numerator and denominator in the ___ direction to maintain consistency and why

Answer 11

same

this consistency will be important for fractions, because differences in the direction of rounding can be compounded in fractions. if you round one up and the other down, you’ve done 2 manipulations to make the final answer larger.

ex: 118/9.81=120/10=12 (real answer is 12.03)

Question 11

how do you multiply and divide fractions

Answer 11

with fraction multiplication, you multiply the numerators and the denominators

when we divide fractions, we multiply by the inverse: (2/4)/(5/6)=(2/4)x(6/5)=(12/20=(3/5)

Question 12

converting between logarithmic and exponential form

Answer 12

loga(c)=b
a^b=c

when logs have no specified base (a is not written), the assumption is log base 10

Question 13

what do you do when the term inside the logarithmic function has an exponent

Answer 13

the exponent can be pulled out to become the coefficient
ex: log(10^3)= 3log(10)

Question 14

how to add logs

Answer 14

combine the terms by multiplying them

log(a)+log(b)=log(axb)

Question 15

how to subtract logs

Answer 15

combine the terms by dividing them

log(a)-log(b)=log(a/b)

Question 16

when the number inside the lpg is 1x10^n, the log of that number is

Answer 16

n

Question 17

general approach to logarithmic estimation

Answer 17

Look at which exponents our number lies between
determine which of those two numbers our value is closer to
make an educated guess as to the approximate value

figure out which two logs your number is between and then figure out which of the two exponent numbers is closer to the original number and then pick the answer closest to that number

ex: -log(3.0x10^-4)
3.0x10^-4 is a number between 1.0x10^-4 and 10x10^-4 (1.0x10^-3)
Therefore, the answer must be between 3 and 4
Since 3.0x10^-4, the answer must be closer to 4, so pick the answer closer to 4

Question 18

scalar quantities

Answer 18

only have magnitude, but no direction

these quantities describe motion, but do not take into account movement on a grid

relevant examples: speed, work, pressure, energy, mass, etc

Question 19

vector quantities

Answer 19

have a magnitude and a direction

vectors take into account the 2 or 3 dimensional space (for the MCAT, it will be 2 dimensional) for the direction of motion

generally speaking, we must separate the x and y components and treat them separately

relevant examples: displacement, velocity, force, weight, etc

Question 20

vector components are based off:

Answer 20

right angle triangles and SOH CAH TOA

Question 21

SOH CAH TOA

Answer 21

sin(θ)=O/H
cos(θ)=A/H
tan(θ)=O/A

Question 22

to combine the vector components to get the resultant vector, we employ the

Answer 22

pythagorean theorem

C^2=A^2+B^2
H^2=A^2+O^2

Question 23

vector addition (highly unlikely to be tested explicitly on the MCAT)

Answer 23

Vector addition is simply connecting two vectors tip to tail, and the resultant vector is simply the line that connects the starting point and the end point

Question 24

vector subtraction (highly unlikely to be tested explicitly on the MCAT)

Answer 24

all you're doing with vector subtraction is adding the negative version of the second vector in other words, A-B is equivalent to A+(-B) with vectors, the negative version is simply a vector pointing in the opposite direction

Question 24

sin and cos 90

Answer 24

sin(90)=1 cos(90)=0

Question 25

sin and cos 0

Answer 25

sin(0)=0 cos(0)=1

Question 26

sin and cos 30

Answer 26

sin(30)= 1/2= 0.5 cos(30)= √3/2= 0.866= 0.9

Question 27

sin and cos 60

Answer 27

sin(60)= √3/2= 0.866=0.9 cos(60)= 1/2= 0.5

Question 28

relevant trigonometric identities to remember

Answer 28

tan(θ)= sin(θ)/cos(θ)

Question 29

slope

Answer 29

rise/run= Δy/Δx = units of y/units of x

Question 30

area under the graph

Answer 30

regardless of the shape, the area can be simplified to bsexheight equates to (units of x) multiplied by (units of y)

Question 31

basic motion graphs: displacement vs time

Answer 31

y axis: has a unit of m x axis: has a unit of s the slope=m/s slope represents velocity the area under the graph: (units of x) x (units of y) = (m)(s) nothing recognizable, so likely not relevant

Question 32

basic motion graphs: velocity vs time

Answer 32

y axis: has a unit of m/s x axis: has a unit of s the slope: m/s^2 the slope represents acceleration the area under the graph: (units of x)(units of y) = (m/s)x(s)= m the area represents the change in displacement

Question 33

basic motion graphs: acceleration vs time

Answer 33

y axis: has a unit of m/s^2 x axis: has a unit of s the slope: m/s^3 nothing recognizable, so likely not relevant the area under the graph: (units of x)(units of y) = (m/s^2)x(s) = m/s area represents the change in velocity

Question 34

what is a force

Answer 34

a force is something that pushes or pulls an object. to be more specific, a force will change the acceleration of an object

Question 35

if acceleration and velocity are in the same direction, the object will _______ if acceleration and velocity are in opposite directions, the object will _______ if an object changes direction due to the acceleration, although its velocity may momentarily be 0, the acceleration is ______

Answer 35

speed up slow down constant

Question 36

constructing a free body diagram

Answer 36

define your system and draw all the relevant sources is there an applied force? if so, include it is there gravity? chances are... yes! does it make contact with another surface? if so, there is a normal force perpendicular to the point of contact is there friction? if so, frictional force will oppose motion (be pointed in the opposite direction of velocity or the direction the object will want to move) Any other special situations? (attached rope for tension force, magnetic or electric forces acting at a distance, thrust, etc)

Question 37

newton's first law (the law of inertia)

Answer 37

an object in motion will stay in motion unless acted upon by an outside force a force will impart acceleration to the object causing it to speed up or slow down lacking that external force, an object will have 0 net acceleration. two scenarios under which the acceleration will be zero: ---constant velocity (Δv=0) ---at rest (v=0)

Question 38

newton's second law

Answer 38

the force acting on an object is directly proportional to the mass of the object and the acceleration produced F = ma, where F (force) and a (acceleration) are both vector quantities this law describes the relationship between force, mass, and acceleration. if you apply a force to an object, the object will accelerate. the amount of acceleration depends on the force applied and the mass of the object ---for example: if you push a lightweight object with the same amount of force as a heavier object, the lightweight object will accelerate more because it has less mass

Question 39

newton's third law

Answer 39

for every action, there is an equal and opposite reaction F_AB = -F_BA or F_AonB=F_BonA this law is all about balance, which is a recurring theme in physics the fundamental tenet of thermodynamics is that energy cannot be created or destroyed, simply changed from one form to another this ensures that total energy within the universe is unchanged in essence, all energy is balanced and this is where action-reaction pair forces stem from in order for a pair of forces to qualify as action-reaction pair forces they must: 1. be equal in magnitude 2. be opposite in direction 3. be the same type of force