173 Questions
How many significant figures are there in the 3.400 g?
4
How many significant figures does the universal gas constant (R = 0.0821 L·atm/mol·K)?
Infinite
How many electrons can fit in the fourth main shell?
32
Which of the following is an extensive property of matter?
Number of moles
Which will cause the mass of a metal block to increase?
none of the above
When two materials that have different densities, like oil and water, encounter one another, they will
separate based on their densities
Which does NOT indicate a chemical change?
change in shape
Mothballs are used as deodorizer and as pesticides. Upon exposing them in air for a few hours, they disappeared. Which of the following best explains the scenario?
The mothballs underwent sublimation
Which of the following is described as having components that can be physically separated?
mixture
It is the statement that contains the result of the experiment and checks if the hypothesis is correct or not.
conclusion
What is the most common isotope of hydrogen?
Protium
Which of the following is TRUE for C-13 isotope?
It has 6 protons and 7 neutrons
A certain radioisotope has a half-life of 9 days. What percentage of an initial mass of this isotope remains after 25 days? (no.15 reviewer)
14.58
Which of the following is NOT a possible set of quantum numbers?
n=3, I=0, ml= -1, ms= -1/2
Which is the correct arrangement for increasing affinity for electrons?
Ne < K < Na < Cl
Which of the following atoms is the largest?
Cs
Which of the following oxides is likely to be basic in aqueous solution?
MgO
Fluorine is capable of forming covalent bonds with which of the following element?
Boron
Chromium is a member of which of the following?
Transition metals
What is an alloy?
Solid solution
Which element is a pale-yellow gas that reacts with water?
F₂
Which of the following is a chemical equation?
C + O₂ ⟶ CO
What is the name of the compound PCl₃?
Phosphorus trichloride
What is the chemical formula of mercurous chloride?
Hg₂Cl₂
Which of the following covalent compounds has a tetrahedral geometry?
CH₄
Which of the following does NOT describe a nonpolar bond?
It has a dipole moment
Which of the following is a polar molecule?
SF₄
Which of the following statements is TRUE?
Single bonds have lower energy than double bonds
Polar molecules include which of these?
I. CO₂ II. COCl₂ III. CH₂CI₂
II and III only
Which compound has the strongest intermolecular force of attraction?
A. CO C. CH₃OH B. CH₄ D. CH₃OCH₃
C
Which of the following is NOT an indication of strong IMFA?
high volatility
Determine the actual volume contained in a 50.0 mL volumetric flask given the following data:
Mass of water: 50.1227 g Density of water at 25°C: 0.99707 g/mL
50.27 mL
At 25°C a gas expands from 30 kPa and 5.0 L to 70°C and 10 kPa. Calculate its final volume.
17 L
According to Revised DAO 04-36, the appropriate waste labels shall Include
All of the above
What happens to the volume of a fully inflated balloon when it is taken outside on a cold day?
Its volume decreases
When water is heated in a beaker, bubbles of air form on the side of the glass before the water boils. This shows that
the solubility of gases in water decreases with increasing temperature
Liquid A has lower boiling point than liquid B. Which of the following is true about the boiling point of the solution formed upon mixing A and B?
between A and B
It is the temperature at which solid and liquid coexist
freezing point of liquid
All solid states are denser than their liquid states. However, water is unique because
Its solid form (ice) is less dense than its liquid form.
How many atoms does a kilogram of copper (63.55 g/mol) metal have?
9.5x10^21
An analysis of a compound shows 62.04% C, 10.41% H, and 27.55% O. Which of the following is the most probably identity of the compound?
C₃H₆O
A 1.00 g sample of which compound will produce the greatest amount of carbon dioxide after complete combustion with excess oxygen?
C₈H₁₈
Which procedure produces a 0.2 M solution of Na₂SO₄?
Mixing 300 mL of 1.2 M NaOH with 600 mL of 0.3 M Na₂SO₄
Which statement is TRUE?
A catalyst speeds up both the forward and reverse reaction rates.
A solution is _______ if more solute can dissolve in it
unsaturated
A solution contains 34.0% HClO₄ by mass. HClO₄ has a molar mass of 100.45 g/mol. The solution has a density of 1.242 g/mL. What is the molar concentration of this solution? (no. 49 reviewer)
4.20 M
A solution has been prepared by transferring 60 mL of 85% by volume H₃PO₄ and diluting it to 1.0 L. What is the concentration of the new solution?
5.10%
Which of the following substances is not basic?
Apple Juice
A 2.4 L of HNO₃ solution reacts with 63 mL of 1.9 N Ba(OH)₂ to produce a neutral solution. What is the molar concentration of the original HNO₃ solution? (no. 59 reviewer)
0.05 M
The following statements are TRUE about pH EXCEPT
It does not change when there are changes in temperature
A solution is prepared by adding 0.1 M H₂CO₃ and 0.1 M NaHCO₃. 0.01 mole HCl is added to 1 liter of the prepared solution. The pH of the resulting is close to? The pKa of H₂CO₃ is 6.37. (WALANG ANSWER AND EXPLANATION)
6.28
When NaCH₃COO hydrolyzes, the resulting solution is
basic
When a strong acid reacts with a weak base during titration, the pH at the equivalence point is
acidic
A lab analyst dissolved 4.021 g of NaOH in water and made up the solution to 1L with water. He then pipetted 10.00 mL of this solution into a flask and titrated it with 0.050 M HCI solution from a burette. A volume of 20.32 mL of acid had been used at the endpoint. Examining this result, the lab supervisor could deduce that _____. (no. 58 reviewer)
the burette was rinsed with water instead of HCI
The Kjeldahl method is the worldwide standard for calculating the protein content in a wide variety of materials ranging from human and animal food, fertilizer, waste water and fossil fuels. It consists of three steps: digestion, distillation, and titration. What element is being analyzed in Kjeldahl method?
Nitrogen
In a galvanic cell, reduction occurs in the ____ while in an electrolytic cell, oxidation occurs in the ____.
cathode, anode
Conductivity is the ability of a substance to
conduct electric current, which is the reciprocal of resistivity
Column chromatography is based on the principle of _
Differential adsorption
Which of the following statements is correct?
The greater the polarity of solute, more strongly it will be adsorbed on a polar surface.
The components of the mixture in column chromatography are eluted in order of
increasing polarity and increasing distribution ratio
Why is it generally preferable to use absorbance as a measure of absorption rather than % transmittance?
because absorbance is proportional to the concentration of the analyte, whereas %T is noT
What will you perform to know that atomic absorption spectrometer continues to work property
Calibration check
A student wants to improve the accuracy of a 9.40 mL liquid using a 100 mL graduated cylinder. Which of the following should he do
use 10 mL graduated cylinder instead
Statistical test that decides whether a datum from a given set could be rejected or NOT is the
Q-test
An analysis of ore assays about 1.5% iron. What minimum sample mass should be taken if the relative error resulting from a 0.5-mg loss is not to exceed -0.2%? (WALA PANG ANSWER AND EXPLANATION)
16.7 mg
For numbers 66-67. See question below.
For a concentration technique, the relationship between the measure signal, Smeas and the analyte's concentration, Ca, is given by equation Smeas = kCA + Sb,. Given the Smeas is 24.37 ‡ 0.02, Sb is 0.96 ‡ 0.02, and k is 0.186 ‡ 0.003 ppm-1
Question for #67: Calculate for the percent relative uncertainty for the analyte’s concentration.
1.6
Report the absolute uncertainty together with the analyte’s concentration.
For a concentration technique, the relationship between the measure signal, Smeas and the analyte's concentration, Ca, is given by equation Smeas = kCA + Sb,. Given the Smeas is 24.37 ‡ 0.02, Sb is 0.96 ‡ 0.02, and k is 0.186 ‡ 0.003 ppm-1
(126 ± 2) ppm
Which of the following focuses on Quality Management Systems?
IS0 9001
It is a part of quality system that includes laboratory operations whose objective is to ensure that the data generated by the laboratory are of known accuracy to some stated, quantitative degree of probability.
Quality Control
Type of quality control sample used to evaluate the effects of sample matrices on the performance of an analytical method
Matrix spike
Locating the adulterated portion of the lot for sampling is an example of _____.
selective sampling
The quantity of material which is assumed to represent a single population for sampling purposes
Lot
What is the name of RA 6969?
Toxic Substances and Hazardous and Nuclear Wastes Control Ac
The responsibilities of chemists and chemical technicians embodied in the Code of Ethics include all EXCEPT
None of the above.
Type of analysis where the amounts of all constituents in the samples are determined.
Complete (or ultimate) analysis
Method consisting a set of instructions issued by a national standards body.
Standard method
It is a detailed written instruction to achieve uniformity in the performance of a specific function.
Standard operating procedure
Which of the following correctly describe/s the detection limit? (ANS. A C AND D)
It would tell the analyst that the element is present, but not necessarily at a precisely determinable concentration level.
Analytical methods or instruments' performance aim for
High signal-to-noise ratio
It accounts for all the other components in the mixture that are not under investigation.
Matrix
When qualifying a working standard, what is the best type of reagent to use?
Primary standard
Requirements of a primary standard.
All of the above
Which of the following is the most appropriate container for hexane?
amber bottle
What type of container should be used when handling or storing hydrogen fluoride?
Polyethylene
the following acids and acid mixtures can be collected and placed in glass containers EXCEPT for
Hydrofluoric acid
Glass container is NOT suitable for
inorganic trace analyses
Ammonia solution can be stored with the following chemicals EXCEPT
acetic acid solution
When working with concentrated acids except hydrofluoric acid, which of the following statements are TRUE? (ANS. A&B)
Gloves covering the whole arm or nitrile gloves should be worn
Which of the following is NOT a proper laboratory practice?
adding water to strong acid
Which of the following is a treatment for HF burns?
calcium gluconate
If a fire extinguisher has a red body and a blue band, what is its content?
Foam type
The following are proper practices in storing materials and equipment EXCEPT ONE.
Store hazardous chemicals inside the fumehood.
Which of the following are possible routes of exposure of the hazardous effects of waste?
All of the above
A solid waste management practice which refers to the controlled decomposition or organic matter by microorganisms, mainly bacteria and fungi, into a humus-like product.
Composting
In handling ethers, the following practices are correct except for one.
Distill these substances to dryness to remove peroxides that were possibly formed from air autoxidation.
What is the type of chemical that can cause an allergic reaction in the airways following inhalation?
Respiratory sensitizer
In order to property maintain chemical laboratory equipment one should perform the following EXCEPT
place the equipment in hot humid location
It is a hazardous waste characteristic which applies to wastes that have the potential to contaminate groundwater if improperly disposed of. These materials are regulated as hazardous waste due to their potential to leach out specific toxic substances in a landfill.
Toxicity
Mass ______.
is the amount of matter that occupies space.
What is the density of oxygen at 1 atm and 25°C?
1.31 g/L
What is the scientific notation of 0.0078 µg/mL of compound A?
7.8x10^-3
A rectangular lot has a dimension of 11.5 by 8.2 feet, what is its area?
94
Convert 250 lb in SI unit
113
Calculate the % yield if 0.85g of aspirin is produced in the reaction of 1.000g salicylic acid with excess oxygen? Given: Acetic anhydride = 102.01// Acetyl salicylic acid = 180.15// Salicylic acid = 138.12// Acetid Acid = 60.05 (no. 43 reviewer)
65
Calculate the % yield when 0.5 mol of acetic acid reacts with 1 mol alcohol produces 0.25 mol of ethyl acetate (no. 44 reviewer)
50
How would you prepare 500.0 mL of 0.2500 M NaOH solution from a concentration of 1000
125
An exact amount of 0.8214g of KMnO4 (158 g/mol) was dissolved in water and made up to volume in a 500 mL vol vol flask (no. 47 reviewer)
8.32x10^-7
Quantitative chemical analysis of weighing a sample usually of a separated and dried precipitate is called
Gravimetric analysis
When samples cannot be dried because they decompose at the temperatures necessary to drive off the water, the samples can be analyzed as
Wet basis
During electroplating of silver, silver ions in solution_____
are reduced at the cathode
Protium, the most common isotope of hydrogen has one proton and one electron. What is its mass?
1.67x10^-27 kg
What is the value of the universal gas constant in cal/mol-K?
1.986
A colorless liquid and a yellowish liquid were mixed in a test tube. Which of the following is incorrect?
There will be no reaction if the test tube will get hot.
Which of the following is TRUE?
Heterogeneous mixtures have phase boundaries.
Which of the following correctly describes H-3 and He-4?
isotones
Whose model illustrates that negative charges are scattered around an atom?
Thomson
What is the wavelength of light (nm) if it has a frequency of 600 THz?
500
Which corresponds to the electron configuration 1s2,2s2,2p6?
Na+
Which group in the periodic table reacts with water at a slower rate to form basic hydroxide solutions?
Group 2
Aqua regia is a/an
solution
Which of the following is expected to have the lowest heat of vaporization?
methylbutane
Which of the following is expected to have the highest vapor pressure?
methylbutane
Which of the following will have the lowest viscosity?
heptane at 30 degree celsius
Which of the following will need the highest work to increase its surface area?
butanol
What is the molar mass of an unknown gas if 1.60 g of that gas occupies a volume of 2.24 L at STP?
16.0 g/mol
What is the partial pressure of methane in a 100-gram mixture of methane and argon (39.95 g/mol) if itis found that argon is 10% by mass and the total pressure is 250 torr?
239 torr
The following are observed characteristics of gases EXCEPT
Pressure exerted by a gas decreases with increase in temperature.
The total volume of an average adult lungs when expanded is about 6 liters. Calculate the pressure of oxygen inhaled if 0.05 mol of oxygen is needed to fully fill a pair of average adult lungs at a normal body temperature of 37 degree celsius
0.212 atm
Tin(II) fluoride (156.7 g/mol) is often added to toothpaste as an ingredient to prevent tooth decay. What is the mass of fluoride (19 g/mol) in 24.6 g of tin(II) fluoride?
5.97 g
The empirical formula of a compound is CH. If the molar mass of this compound is about 78 g, what is its molecular formula?
C6H6
For which compound are the empirical and molecular formulas the same?
C6H5COOH
Consider the combustion of butane C4H10 + O2 → CO2 + H2O where in a particular reaction, 5 mol of C4H10 are reacted with an excess of O2. Calculate the mol of CO2 formed.
20 mol
For the reaction SO2 + O2 → SO3, what is the maximum weight of SO3 (80 g/mol) that can be produced from 40.0 g of SO2 (64 g/mol) and 8.0 g of O2 (32 g/mol)?
40.0 g
Ammonia is produced in according to the equation N2 + 3H2 → 2NH3. In a particular experiment, 0.25mol of NH3 is formed when 0.5 mol of N2 is reacted with 0.5 mol of H2. What is the percent yield?
75%
A solution has 3x10-4 M Cu2+, convert this into ppm (Cu 63.55 g/mol).
19 ppm
How many grams of NaOH (40 g/mol) is needed to prepare 500 mL of 0.500 N solution of NaOH?
10.0 g
An exact amount of 0.8214 g of KMnO4 (158 g/mol) was dissolved in water and made up to volume in a 500-mL volumetric flask. A 2.00-mL portion of this solution was transferred to a 1000-mL flask and diluted. Then 10.00 mL of the diluted solution was transferred to a 250-mL flask and diluted to volume. What is the molar concentration of the final solution?
8.32x10^‒7 M
Which molecular geometry has the greater bond angle?
Linear
What is the name of the compound indicated? Pb(ClO)4
Plumbic hypochlorite
What is the other name for oil of vitriol?
Sulfuric acid
From top to bottom down the periodic table?
Electronegativity decreases
From left to right across the periodic table?
Atomic radius decreases
Alcohols and carboxylic acids have -OH groups. What type of chemical bonding occurs between the oxygen and hydrogen atoms?
Polar covalent
It is a result of instantaneous dipole in non-polar molecule?
Van der Waals forces
Which among the following compounds has the lowest boiling point?
Benzene
What IMFA is/are present in the compound indicated? H3C(CH2)3CHO
Van der Waals and dipole-dipole interactions
A cylinder containing a gas is compressed to half its original volume. What will happen to its pressure at constant temperature?
Doubled
A 30-L gas initially has 110 kPa and 147 ℃. If its volume become 40 L and the pressure increased to 120 kPa, what is the new temperature (℃)?
338
What is the pressure (atm) of hydrogen if it has 0.412 mol at 16℃ in a 3.25L?
3
For numbers 151-152. Nitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at high temperature. The other products of the reaction are solid copper and water vapor as shown in the reaction below.
NH3(g) + CuO(s) N2(g) + Cu(s) + H2O(g)
If 30.5 g of NH3, is reacted with 99.7 g of CuO, how much excess reactant will remain?
16.3 g
Based on the previous problem, how many grams of water vapor will be formed?
22.6 g
Which of the following is a chemical reaction?
Bleaching your clothes
A white powder is analyzed and found to contain 43.64% phosphorus and 56.36% oxygen by mass. The compound has a molar mass of 283.88 g. What is the molecular formula of the compound?
P4O10
How many grams of potassium dichromate is required to prepare 250 ml of 0.1M solution of potassium dichromate? This solution is an oxidizing agent used in organic chemistry?
7.35 g
What is the molarity of 37% w/w hydrochloric acid? The density of 37% w/w HCl is 1.18g/mL
12 M
A polar solute usually dissolves in a polar solvent and a nonpolar solute usually dissolves in a nonpolar solvent. This is
The ‘like dissolves like” rule
The synthesis of ammonia from nitrogen and hydrogen is an exothermic reaction. Which of the following will favor the formation of ammonia?
Decrease in temperature
Under the Brꬾnsted-Lowry concept of acids and bases, a base is a/an
Proton acceptor
Determine the concentration of H+ ions in apple cider vinegar if the pH was measured to 3.57.
2.7 × 10-4 M ??????//
In which of the following titrations does pH = 7.0 occur at the equivalence point?
Strong acid/ strong base
A type of analysis in terms of sample size that can resolve fine-scale variations in chemical elements, as well as determine the presence and distribution of different phases in materials
Micro
An analyst determines that the analytical balance he used in a given analytical test is wrongly calibrated. Determine what type of error is represented.
Systematic error
It is a plot of an instrument’s readout vs. concentration, the data for which are the results of measuring a series of standard solutions prepared for the experiment.
Calibration curve
It describes the policies and procedures the laboratory has to manage in relation to quality, or references where those procedures can be found. An essential requirement of ISO 9000 series of standards and ISO 17025.
Quality Manual
An exposure limit that indicates the maximum average concentration to which workers can safely be exposed for a normal 8-hr workday or 48-hr workweek
Time weighted average (TWA)
are bulk materials that are partially packed into smaller units, such as bags or drums
Segments
Is comprised of identifiable units, which may bee assigned numbers
Packed material
Refers to a single pile of material. Not in the form of separate permanently identifiable units
Bulk Material
is a quantity of the material transferred on one occasion and covered by a single set of shipping documents
Consignment
refers to quantity of material which is known or assumed to have been produced under uniform conditions
Batch
are portions of the material obtained from the lot/batch by using a sampling device
Increments
is the result of combined increments. In some cases, Laboratory samples are directly obtained from primary samples
Primary or gross samples
results from a number of primary samples combined and mixed
Composite or aggregate samples
Test your knowledge of significant figures, gas constants, electron shells, and properties of matter with this quiz. Explore concepts such as extensive properties of matter and factors affecting the mass of a metal block.
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