CHM 2032 LAB MIDTERM (5 Labs)
5 Rules of Lab Safety
1. recognize hazard 2. know protection 3. use protection 4. know the response 5. apply the response in time
Express number in proper exponential notation. 104,544
1.04544 x 10^5 0.00003456 3.456 x 10^-5 567,345,956 5.67345956 x 10^8
How many cm from the top of chromatography paper,should you stop the process?
1.5 cm
1 kg = ? grams
1000 grams
how do you find the mass of water in kg
1000 mL= 1 kg
Calculate the slope if rise is 6 and run is 1.5
4
proteins and carbs good energy
4.0 Cal/g
Solve and express your answer in proper exponential notation. (4.63 X 10^6) - (5.6 X 10^4)
4.574000 x 10^6
How many significant figures? 8.1035 X 10^33
5
Express number in proper exponential notation. 567,345,956
5.67345956 x 10^8
sig figs in 1010.00
6
Chromatography
A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material.
graph
Diagram that represents the variation of one system factor in relation to the resulting variation of one or more other factors.
when dividing exponential numbers...
subtract the powers
extrapolation
projection; conjecture; stretch
specific gravity
ratio of a mineral's weight compared with the weight of an equal volume of water
Rf
ratio of distance traveled by component/ distance traveled by solvent front
Density is..........? (definition)
ratio of mass to its volume
specific gravity
ratio of the density of a substance to the density of a reference substance
combustion reaction
reaction with O2 (a reaction of peanut oil with oxygen; digestion)
If there is an accident, what should you do to be helpful and correct the problem?
recognize the hazard
Use when needed and know location of safety shower,fire blanket,first aid and shut off valves
safety equipment
exponential term
second factor in exponential notation (10)
When stapling the chromatography paper, edges
should not overlap
In case of a fire do this......
smother with a towel
exponent
specific whole number power (^x)
When adding/subtracting exponential numbers...
they need the same power. If they do not match, you must convert
inexact numbers
those whose values have some uncertainty
what is always an independent variable?
time
Calculate the amount of energy released per gram of peanut burnt, given 8 Cal of released energy and 0.5g of peanut to start with.
total amount of energy released/mass of peanut burned 8/0.5=16 Cal g
Triglycerides
triester produced by the reaction of glycerol with three fatty acids (peanut oily)
Miscible
Describes two liquids that are soluble in each other (Rubbing alcohol dissolves in grain alcohol)
broken glass
goes in designated conatiner
safety apparel
goggles, aprons, gloves
Express number in proper exponential notation. 0.00003456
3.456 x 10^-5
less dense
...... will float on top of the more dense
Round off number to 3 significant figures. 0.0256759
0.0257
Calculate the mass, in kg of water present in the calorimeter, using Equation 6, if you have 200mL of water.
0.20 kg (mass, kg= density * volume (L)) density = 1.0 200 mL times 1L/1000mL=0.20kg
Calculate the mass of burnt peanut if starting weight is 0.965g and 0.0134g after burning.
0.9516g (INITIAL WEIGHT - AFTER BURNING)
Select all correct answers. 1. Do not bump other students 2. No Roaming 3.Immediately report any accident,injury or incorrect procedure. 4.If you have an idea of an experiment, try it out.
1,2,3
Complete the following calculation and express using proper significant figures. B. 5.344 + 0.7345 + 12.9 + 0.0345
19.0
1cm^3=
1mL pure water
Complete the following calculation and express using proper significant figures. A. 8.434/4
2
Solve and express your answer in proper exponential notation. (3.40 X 10^-6/6.34 X 10^4) + (2.00 X10^-4)
2.000000536 x 10^-4
Round off number to 3 significant figures. 264.45
264
How many significant figures? 20400
3
Solve and express your answer in proper exponential notation. (4.6 X10^-5)+ (3 X10^-3)
3.046 x 10^-3
fat's food energy
9.0 Cal/g
exothermic reaction
A reaction that produces heat i.e. burning peanut
Density equation
D=m/v
significant figures rules
Non-zero digits are always significant. Any zeros between two significant digits are significant. A final zero or trailing zeros in the decimal portion ONLY are significant.
exact numbers
Numbers that have no uncertainty and thus do not limit the number of significant figures in any calculation.
Why keep the beaker with solvent covered?
Prevent evaporation
stationary phase
The phase that does not move in chromatography. (liquid or solid)
ordinate
The y-axis is called the _______.
Why is it important to mark origin and solvent front?
This is needed to calculate the Rf
line graph
Used to compare the values of 2 variables.
What is the correct order to record mass of a liquid into a graduated cylinder?
Weigh the empty cylinder, add liquid, reweigh cylinder
Immiscible
liquids that are not soluble in each other (oil and water)
origin of chromatography
location of the spotted area
specific heat capacity of water
_______ is 1.0 cal per g per degree Celsius
Calorimeter
a measuring instrument that determines quantities energy released
The x-axis is call the _________.
abscissa
when multiplying exponential numbers...
add the powers
amount of energy released per gram
amount of energy released / mass of the peanut
paper chromatography
apply/spot a sample of the mixture we wish to separate near the bottom of the paper
Use only
authorized material and equipment
Contact Lenses can be worn in the lab anytime there is chemical use that may infuse under the lens?
can NOT be worn in the lab anytime there is chemical use that may infuse under the lens
soluble
capable of being dissolved (sugar in water)
specific gravity equation
density of substance/density of water
characteristic
digits to the left of the decimal
mantissa
digits to the right of the decimal
Rf (retention/retardation factor) formula
distance traveled by component(cm)/distance traveled by solvent front(cm)
safety is
everyone's responsibility
exponential notation
expresses numbers as the product of two factors
there are makeup labs
false
Digit term
first factor in exponential notation (x)
PHYSIOLOGIC ENERGY equals
food energy
Choose all that are not allowed in the lab?
food,drink, personal belongings, touching chemicals with hands
how do you find mass of peanut
initial mass - post mass
cannot be dissolved (Plastic soda bottle floats on a pond)
insoluble
when decimal place is moved to the right in exponential notation...
it is negative
when decimal place is moved to the left in exponential notation...
it is positive
you lose points when...
late for class
adding and subtracting sig figs
least number of decimal places
multiplying and dividing sig figs
least number of sig figs
slope formula
m=y2-y1/x2-x1 OR RISE/RUN
how do you find the amount of energy released from the burning peanut
mass of H2O x change in T x specific heat of water (which is 1.00)
Calculate the amount of energy released in Cal from the burning peanut given mass of 0.4kg of heated water, 16 degree Celsius water temperature increase.
mass times temperature change time specific heat of water (1.0) 16 times 0.4 times 1 = 6.4 Cal
What causes the rate of mixture to move apart(seperate from one another) during chromatography?
molecular structure differences
graphing calculators are
not allowed on the final
Iodine is
not safe to touch with hands
fatty acids
organic acids with long,unbranched chains of twelve or more carbon atoms
What will be used as the stationary phase
paper
______ is 9,0 Cal per gram
physiological energy for lipids
Energy definition
the ability to do work
solvent front
the furthest point reached by the solvent/leading edge of the mobile phase
Thomas seng is
the instructor
food produces...
the same amount of energy
significant sig figs in logs/antilogs
the sig figs to the right of the decimal (mantissa) are equal to the total amount of sig figs in the original number
What will be used as the mobile phase?
water/salt
mobile phase of chromatography
where the molecules can move, always a liquid or gas
Review safety
with your instructor before beginning
Using this slope of 10, if y-intercept is +45, write the equation for the line
y= 10x+45
What is the general equation of a line graph?
y=mx+b
in chromatography you need...
you need dry samples
