anachemerut Flashcards
(213 cards)
1
Q
Important tool in measuring mass of materials.
A
Laboratory balance
2
Q
Different kinds of balances are used in the laboratory depending on the __________ and __________ on the equipment.
A
sensitivity; readability
3
Q
The smallest weight that will produce a certain measurable response.
A
Sensitivity
4
Q
The smallest discernible scale division and may or not be the sensitivity of the equipment.
A
Readability
5
Q
Ability of the measuring device to produce a certain response to a certain numeric response or measurement that’s certain and will give the experimenter a good approximate of the amount of a certain material.
A
Sensitivity
6
Q
We may have readable equipment but not sensitive enough.
A. True
B. False
A
True
7
Q
Readability of the top-loading balance.
A
0.01 – 0.001 g
8
Q
Laboratory balance that has a rough approximate.
A
Top-loading balance
9
Q
It produces steady readings in wider environmental conditions.
A
Top-loading balance
10
Q
It can be used in any type of weather systems or environmental conditions whether the temperature of the room is humid or a little bit cooler.
A
Top-loading balance
11
Q
Doesn’t offer protection from air disturbances because it doesn’t have a draft shield.
A
Top-loading balance
12
Q
Top-loading balance is accurate as the analytical balance.
A. True
B. False
A
False
13
Q
Can only used for large measurements.
A
Top-loading balance
14
Q
Capacity of the top-loading balance.
A
600 – 34,000 g
15
Q
Top-loading balance is almost the same with an analytical balance.
A. True
B. False
A
True
16
Q
In using a top-loading balance, keep it clean before and after use.
A. True
B. False
A
True
17
Q
High sensitive instrument designed for accurate weight measurement.
A
Analytical balance
18
Q
Readability of analytical balance.
A
0.1 – 0.01 mg
19
Q
Extremely sensitive and measurements are affected by air currents.
A
Analytical balance
20
Q
Analytical balance must be covered by a draft shield.
A. True
B. False
A
True
21
Q
It is a plastic glass or cover that prevents air from interfering with measurements.
A
Draft shield
22
Q
Top-loading balance is more sensitive and it is used for standard measurements.
A. True
B. False
A
False
23
Q
Capacity of analytical balance
A
320 g
24
Q
Samples beyond the capacity of analytical balance will yield inaccurate measurements.
A. True
B. False
A
True
25
We should take note of the maximum capacity of the analytical balance.
A. True
B. False
True
26
It is designed for heavier substances.
Analytical balance
27
The maximum capacity of the analytical balance varies among manufacturers.
A. True
B. False
True
28
It is fine to place the analytical balance on a wobbly table as long you can measure your sample.
A. True
B. False
False
29
An unbalanced or misaligned table will disrupt the accuracy of the measurement of an analytical balance.
A. True
B. False
True
30
Place the analytical balance near doorways or sources of strong wind currents.
A. True
B. False
False
31
Before using the analytical balance, you should always check the __________ if it is properly aligned in the middle of the circle for proper calibration.
Spirit bubble
32
Clean the analytical balance before and after use with a soft bristle brush.
A. True
B. False
True
33
The balance is placed on top of a stable counter table to avoid __________.
vibrations
34
Analytical balance should be placed in a room with a lot of air fluctuations.
A. True
B. False
False
35
By placing the analytical balance with a minimal air fluctuations, it will minimize errors during weighing.
A. True
B. False
True
36
Chemicals shouldn’t be placed directly on the pan because it’s subject to corrosion.
A. True
B. False
True
37
The balance is made of iron so it can easily be oxidized (rust).
A. True
B. False
True
38
You should use glassware such as weighing bottle or beaker to serve is container for chemicals to be weighed.
A. True
B. False
True
39
Weighing Paper: Used for small quantities
Weigh Boat: Used for large quantities
A. True
B. False
True
40
If something is spilled on the pan during weighing, clean it up as soon as possible.
A. True
B. False
True
41
Weigh objects or chemicals at room temperature.
A. True
B. False
True
42
Warm, hot objects, or chemicals can create convection air current, producing air fluctuations around the balance pan that can be difficult to obtain a stable reading. Thus, all materials that we’ll be measuring must be at room temperature.
A. Both statements are true
B. Both statements are false
C. Only the first statement is true
D. Only the second statement is false
Both statements are true
43
The balances, especially for analytical balance, must be set at an operating temperature, especially after turning on the equipment.
A. True
B. False
True
43
The balances, especially for analytical balance, must be set at an operating temperature, especially after turning on the equipment.
A. True
B. False
True
44
Weigh only dry objects or chemicals because moisture can corrode the balance pan.
A. True
B. False
True
45
Approximate weight measurement should be on a top-loading balance while accurate weight measurement on an analytical balance.
A. True
B. False
True
46
Always use the same balance if it requires more than one weight measurement.
A. True
B. False
True
47
Most common type of measurements in the laboratory.
Volume measurements
48
Laboratory glasswares
Pipette
Burette
Graduated cylinder
49
Type of glassware refers to laboratory apparatus designed to deliver the specific volume at the calibration temperature.
To deliver
50
It always transfers the same exact volume between instruments.
To deliver
51
All TD-type glassware is calibrated in milliliters (mL).
A. True
B. False
True
52
In the burette, the zero mark is always on the top. On the other hand, the zero mark of the pipette is at the bottom.
A. True
B. False
True
53
Glasswares that contain exact volume but cannot transfer the same amount.
To contain
54
Zero (0) mark is usually on the top.
To deliver
55
Zero (0) mark is usually on the bottom.
To contain
56
Examples of TC glasswares.
Volumetric flask
Graduated cylinder
57
When aqueous solutions wet the wall of any TD-type glassware, it produces a __________.
Meniscus
58
A shallow curve on the surface of the liquid.
Meniscus
59
The bottom of the meniscus is the level of the solute.
A. True
B. False
False
60
To estimate the volume properly, the eye should be at the same level as the bottom of the meniscus to avoid parallax error.
A. True
B. False
True
61
In parallax error, reading above the eye level results to lower reading than the accurate volume measurement. While reading below the eye level will result to higher reading than the accurate volume measurement.
A. Both statements are true
B. Both statements are false
C. Only the first statement is true
D. Only the second statement is true
Both statements are true
62
The meniscus formed by the aqueous solution can either be __________ or __________.
concave; convex
63
Meniscus produced by transparent or colorless liquids.
Concave
64
Meniscus produced by dark-colored solutions.
Convex
65
Do not attempt to reach the height of the measurement yourself like standing on a chair to reach eye level.
A. True
B. False
True
66
The final volume of the measured substance must include both certain and uncertain values.
A. True
B. False
True
67
In reading a graduated cylinder, if you need to reduce the amount of liquid, use a dropper or
a pipette.
A. True
B. False
True
68
Glassware used to accurately deliver.
TD glasswares
69
Glassware used to accurately deliver single volume of liquid.
Volumetric pipette
70
Glassware used to accurately deliver variable volume of liquid.
Measuring pipette
71
Unlike a graduated cylinder, the 0mL graduation mark is found almost at the __________ part of the pipette.
top
72
For the pipette (and even burette), the volume is read __________ the liquid has been dispensed.
after
73
Pipettes that have no graduations and delivers only specific amounts.
Volumetric
74
Pipettes that have graduations but until the tip.
Mohr
75
Pipettes that have graduation until the tip and is more accurate.
Serological
76
Pipettes that need a rubber aspirator to deliver all its contents and possesses a double bands on its end.
Blowout
77
The two arms of a burette clamp can accommodate two titration set-ups at a time.
A. True
B. False
True
78
Types of burette.
Mohr's
Geissler's
79
To fill up the burette with a solution, make sure that the stopcock is in a vertical manner.
A. True
B. False
False
80
Add a small amount of solution to be transferred and then rotate the burette horizontally to wet the interior completely.
A. True
B. False
True
81
Drain the liquid through the tip by opening the stopcock in a horizontal manner.
A. True
B. False
False
82
Fill the burette with the solution up to a level above the zero mark.
A. True
B. False
True
83
Free the tip from air bubbles by opening the stopcock, permitting the solution to pass through the tip.
A. True
B. False
True
84
If the solution is below the zero mark, add more
solutions using a beaker and you should note the initial volume reading.
A. True
B. False
False
85
Place the tip of the burette within the titration vessel which is usually a/an __________.
Erlenmeyer flask
86
Always use a florence flask and beaker as the titration vessel.
A. True
B. False
False
87
The tip of the burette should be a few inches above the receiving vessel.
A. True
B. False
True
88
Deliver small amounts of solution into the vessel by slowly opening the stopcock.
A. True
B. False
True
89
Swirl the vessel constantly to ensure completeness of the reaction between reactants.
A. True
B. False
True
90
In performing titration, add the solution dropwise when the endpoint is near. This point can be observed when there is development of persistent color.
A. Both statements are true
B. Both statements are false
C. Only the first statement is true
D. Only the second statement is false
Both statements are true
91
In performing titration, one hand is opening the stopcock while the other hand of the experimenter is slowly swirling the solution in the Erlenmeyer flask.
A. True
B. False
True
92
In performing titration, a colorful background can be used for easy visualization of the endpoint.
A. True
B. False
False
93
If the reaction is judged to be complete, let the stopcock open and then take note of the final volume reading.
A. True
B. False
False
94
The volume of solution delivered into the vessel is the product between the final and initial volume readings.
A. True
B. False
False
95
A glassware used for dilution and preparation of solutions.
Volumetric flask
96
A pear-shaped, flat-bottomed flask with a long, narrow neck that has an etched graduation mark.
Volumetric flask
97
When a solution has filled up the flask up to the marking, this means it contains the volume as indicated on the label of the flask.
A. True
B. False
True
98
The reason why the volumetric flask is a “To Contain” type glassware because it will contain a specified volume of liquid at a particular temperature.
A. True
B. False
True
99
In preparing solutions using a volumetric flask, a weighed solid reagent is dissolved in a beaker with a minimum volume of solvent which usually __________.
water
100
The solution is transferred into the volumetric flask, using a __________ to direct the flow of the liquid.
stirring rod
101
Rinse both the stirring rod and the beaker with distilled water and transfer the washings to the volumetric flask and repeat this step at least two more times.
A. True
B. False
True
102
Half-fill the volumetric flask with the solvent and swirl the contents.
A. True
B. False
True
103
Add more solute to the volumetric flask until the level of the liquid almost reaches the mark.
A. True
B. False
False
104
You may use a dropper for final additions of solvent.
A. True
B. False
True
105
The bottom of the meniscus should be at the same level as the graduation mark.
A. True
B. False
True
106
When the substance goes over the graduation mark, it is no longer usable and should be discarded to start over.
A. True
B. False
True
107
You should cover the flask with a stopper.
A. True
B. False
True
108
Perform multiple Inversions to make a homogenous solution.
A. True
B. False
True
109
Transfer the contents into storage bottle.
A. True
B. False
True
110
Rinse the reagent bottle with a small amount of the prepared solution, discard the rinsing, and transfer the solution into the bottle and cover and then label the bottle.
A. True
B. False
True
111
Several tests should be made to prove the validity of data and is done through replicate analysis.
A. True
B. False
True
112
Refers to the agree of a particular value with the real value.
Accuracy
113
Refers to the degree of agreement among several measurements made in the same manner.
Precision
114
It answers the question how close it is to the true value.
Accuracy
115
It answers the question how close the values are to each other.
Precision
116
Data can be precise and inaccurate or accurate but not precise.
A. True
B. False
True
117
It is the estimated digit.
Uncertainty
118
Measurement always has some degree of uncertainty.
A. True
B. False
True
119
Which of the following are reasons for uncertainty?
A. Measurements are performed with instruments
B. No instrument can read to an infinite number of decimal places
C. Both of the choices
D. None of these
Both of the choice
120
Higher sensitivity results to lower uncertainty.
A. True
B. False
True
121
You can easily read the temperature on a thermometer to the nearest degree.
A. True
B. False
True
122
You can also estimate the temperature to
about the nearest tenth degree by noting the closeness of the liquid inside to the calibrations.
A. True
B. False
True
123
In 22.9 C, which is the certain measurement?
22
124
In 22.9 C, which is the uncertain measurement?
0.9
125
Includes all the digits that are known and a last digit that is estimated.
Significant figures
126
Measurements must always be reported to the correct number of significant figures because calculated answers cannot be more precise than measured data.
A. True
B. False
True
127
Every nonzero digit is significant.
A. True
B. False
True
128
Rounding off constants are not taken into consideration when deciding the number of significant figures.
A. True
B. False
True
129
A calculated answer cannot be more precise than the least precise measurement from which it was calculated. The calculated value must be rounded to make it consistent with the measurements which it was calculated based on the number of significant figures
A. Both statements are true
B. Both statements are false
C. Only the first statement is true
D. Only the second statement is false
Both statements are true
130
The answer to an addition or subtraction calculation should be rounded to the _____________________ as the measurement with the _____________________.
same number of decimal places; least number of decimal places
131
In calculation multiplication and division, round the answer to the same number of significant figures as the measurements with the __________ number of significant figures
least
132
Measurements unvaryingly involve errors and uncertainties that could be due to:
I. Mistake on the part of the experimenter
II. Inaccurate calibrations
III. Faulty standardizations
IV. Random variations in the results
A. I only
B. I and II only
C. I, II, and III only
D. All of these
All of these
133
Measurements of uncertainties can never be eliminated.
A. True
B. False
True
134
Data can only give an estimate of the “__________”.
true value
135
Calculation of the probable magnitude of error is necessary to define limits of the true value.
A. True
B. False
True
136
Data validity is confirmed through __________.
statistical analysis
137
Data validity is confirmed through statistical analysis to:
A. Sharpen scientific judgement for data quality
B. Determine similarity or difference in the set of obtained data
C. Both of the choices
D. None of the above
Both of the choices
138
The analytical results are free of errors and uncertainties.
A. True
B. False
False
139
You can only minimize errors and estimate their size with acceptable accuracy.
A. True
B. False
True
140
We can reduce errors to a number with acceptable accuracy.
A. True
B. False
True
141
Use to judge the quality of experimental measurements are many.
Statistical calculations
142
We can measure the amount of error present in our data and that will be the measure of how accurate and how precise our data and experiment procedures are.
A. True
B. False
True
143
Measurements are always accompanied by uncertainty.
A. True
B. False
True
144
The experimental value of a measurement is never known exactly or it’s hard to determine the exact measurement.
A. True
B. False
False
145
Defines the limit within which the true value lies.
Probable magnitude of the error
146
Data of unknown quality are worthless.
A. True
B. False
True
147
Measurement of errors will be our indicator of data quality.
A. True
B. False
True
148
The true value of a measurement is always known exactly.
A. True
B. False
False
149
Error due to procedural/instrumental factors that cause a measurement to be consistently too large/small.
Determinate or Systemic Errors
150
Errors that we can define/determine/measure, thus we can correct these errors.
Systemic errors
151
Errors with a known source.
Systemic errors
152
Type of error that’s always found in every experiment.
Systematic errors
153
Affect measurements in one and only way, and can, in principle, be accounted for.
Systemic errors
154
Key feature of systemic errors.
Reproducible
155
The following are characteristics of systematic error except:
A. Consistent but can be detected and corrected.
B. Too high or too low values
C. May lead to bias in measurement techniques and affects accuracy
D. C only
E. All of the above
All of the above
156
Types of systematic error
Instrumental errors
Method errors
Personal errors
157
Caused by non-ideal instrument behavior, faulty calibrations or by use under inappropriate conditions.
Instrumental errors
158
All of the following are example of instrumental errors except:
A. Imperfect Measuring Devices
B. Calibration issues
C. Inability to maintain operating abilities of equipment
D. Reaction rate
Reaction rate
159
Errors from non-ideal chemical or physical behavior of analytical systems like instability of chemical species, slow reaction rate and etc.
Method errors
160
Result from carelessness, inattention, or personal limitations of the experimenter.
Personal errors
161
Which of the following are ways to detect systematic errors?
A. Analyze a known sample, such as a certified reference material
B. Use of blank samples
C. Use of different analytical methods to measure the same quantity
D. Round robin experiment
E. All of the above
All of the above
162
Set of experimental samples.
Blank samples
163
Doesn’t contain the analyte of interest.
A. Blank
B. Analyte
Blank
164
Substance that is being investigated.
A. Blank
B. Analyte
Analyte
164
The Blank samples could contain reagents or diluents that may act as interferences in the experiment
A. True
B. False
True
165
The phrase used to collectively call analytical techniques that measure the quality and quantity of a sample/experimental procedure based on the standard operating procedures (SOP).
Golden standard
166
Some golden standard procedures are preferred in certain experiments that will give us high yield of highly accurate and precise data.
A. True
B. False
True
167
In __________ experiment, make sure that you duplicate or replicate the experiment. Repeat the experiment as many times as possible or for at least 3 times.
Round robin experiment
168
Reproducible experiment is a good indicator of quality data.
A. True
B. False
True
169
Which of the following is/are ways to minimize and correct systematic errors?
A. Proper training
B. Practice regular maintenance of equipment and calibration
C. Well-kept of notebook to note unusual trends and identify the source of errors.
D. None of these
E. All of the above
All of the above
170
Uncertainties resulting from the operation of small uncontrolled variables that are inevitable as measurement systems are extended to and beyond their limits.
Random or Intermediate Error
171
Errors that affect precision
Intermediate error
172
Type of error, which can be either positive/negative and cannot be eliminated, based on the ultimate limitations on a physical measurement.
Intermediate error
173
Hard to determine the source of error, and at most, they can’t be measured.
Intermediate error
174
Occasional error that may cause results in the occurrence of a questionable outlier.
Gross error
175
Occasional result in replicate measurements
that differs significantly from the rest of the results.
Outlier
176
Test used to detect outlier.
Q-Test
177
Rejection Quotient that determines whether a suspected outlier should be accepted or rejected.
Q-Test
178
Outliers can be also detected by the use of Grubbs Test.
A. True
B. False
True
179
Central or average value
Mean
180
The most representative value for a set of
measurements or data.
Mean
181
Middle value in data set that is arranged in numerical order.
Median
182
Advantageous for data with outlier.
Median
183
Most frequently occurring number in a data set.
Mode
184
Gives a rough idea on how widely spread out the most extreme observations are.
Range
185
The difference between the largest (HV) and smallest value (LV) in the data set.
Range
186
A measure of data variability/ dispersion around the mean of a sample of population.
Sample standard deviation
187
The smaller the standard deviation, the more closely the data are clustered about the mean.
A. True
B. False
True
188
Indicates how the mean varies with different experiments measuring the same quantity.
Standard Error of the Mean
189
A precision estimate consisting the square of the standard deviation.
Variance
190
Explains data that it is tightly clustered around the mean.
Relative standard deviation
191
Also known as % RSD
Coefficient of Variation
192
Difference between the measured value and the true value.
Absolute error
193
Measure of the uncertainty of measurement compared to the size of the measurement.
Relative error
194
Percentage of error between the measured value against the true value.
Percent error
195
Also known as Dixon’s Q-test
Q-test
196
Widely used statistical test for deciding whether a suspected result should be retained or rejected.
Q-test
197
Q > Qcrit
A. Reject
B. Retain
Reject
198
In most quantitative analyses, the true
value of the population mean μ cannot be determined because a huge number of measurements (approaching infinity) would be required.
Confidence limit
199
The range of values within which the population mean μ is expected to lie within a certain probability.
Confidence intervals
200
Boundaries of the confidence interval.
Confidence limits
201
Probability that the true mean lies within
the certain interval.
Confidence level
202
Probability that the result is outside the confidence interval.
Significance level
203
Statistical tests to compare individual or sets of values for significant differences.
Significance testing
204
Designed to indicate whether there is a significant difference between two methods based on their SD.
F-Test
205
It is assumed that both data set have essentially the same SD which is first verified by F-test.
T-test
206
Property of a mathematical relationship or
function which means that it can be graphically represented as a straight line.
Linearity
207
A way to model a relationship between two sets of variables.
Linear Regression Analysis
208
A linear approach to modelling the relationship between a scalar response (or dependent
variable) and one/more explanatory variables (or
independent variables).
Linear Regression
209
Independent variable : concentration
X-axis
210
Dependent variable : absorbance
Y-axis
211
A measure of how close the line fits the points that you found in your experiment.
Coefficient of Determination
