Chemistry Exam Quiz (PUM 2022) *Top secret lol*
Chemistry Exam Challenge
Test your knowledge and understanding of chemistry concepts with our comprehensive quiz designed for students and enthusiasts alike. This quiz covers a range of topics from ionic compounds to enzymatic reactions, ensuring a well-rounded assessment of your chemistry skills.
Key features:
- 30 Multiple Choice Questions
- Instant Feedback on Your Answers
- Diverse Topics in Chemistry
Empirical Van't Hoff rule says that:
1. for most of the reactions, increase in temperature by 10°C causes 10 times an increase in the reaction rate
2. for most of the reactions, increase in temperature by 5°C causes 2 to 4 times an increase in the reaction rate
3. for most of the reactions, increase in temperature by 10°C causes 2 to 4 times an increase in the reaction rate
4. for most of the reactions, increase in temperature by 5°C causes 5 times an increase in the reaction rate
Formulas of ionic compounds:
1. if the ions have the same charge, only one of each ion is needed
2. if the ions have different charges, however, unequal numbers of anions and cations must combine in order to have a net charge of zero
3. when the two ions have different charges, the number of one ion is equal to the charge on the other ion
4. the sum of charges on the ion in a formula unit equals zero
Reactive oxygen species (ROS):
1. can be formed by two ways: enzymatic and non-enzymatic reactions
2. at low-to-moderate amounts are involved in modulation the expression of genes activated transcription and proliferation
3. their overproduction in the body that causes damage to the biomolecules (cells) of the body is called oxidative stress
4. are generated from either endogenous or exogenous sources
The group of hydrophilic antioxidants includes:
1. vitamin C
2. vitamin E
3. glutathione
4. coenzyme Q
5. carotenoids
Formation of ionic compounds:
1. main-group non-metals lose electrons to form cations and attain an electron configuration like that of noble gas just before them in the periodic table
2. main-group metals lose electrons to form cations and attain an electron configuration like that of noble gas just before them in the periodic table
3. main-group non-metals gain electrons to form anions and attain an electron configuration like that of the ne noble gas just after them in the periodic table
4. main-group metals gain electrons to form anions and attain an electron configuration like that of the noble gas just after them in the periodic table
5. ionic bond is formed when electrons are transferred from metal to non-metal
Hydrophilic colloids:
1. show lower stability than hydrophobic colloids
2. show higher stability than hydrophobic colloids
3. are acting protective on hydrophobic colloids
4. have large affinity to solvent particles
Choose true sentences:
1. catalyst is a substance that speeds up the rate of a chemical reaction but is itself unchanged
2. after adding the catalyst, the equilibrium is reached more quickly but value of equilibrium constat K is unchanged
3. Le Châtelier's principle predicts that an increase in temperature will cause an equilibrium to shift in favor of the endothermic reaction so the additional heat is absorbed
4. entropy (S) is a measure of the amount of molecular disorder in a system
Ionic compounds:
1. do not conduct electricity when they are solid
2. are usually soluble in water
3. have low melting and boiling points
4. are hard, rigid and brittle - they shatter when they are hit
Activation energy (E_act):
1. is the difference between the energy of bonds broken in reactants and the energy of bonds formed in products
2. is the amount of energy necessary for a reaction to occur and it determines the reaction rate
3. the lower E_act, the lower the number of productive collisions, and the slower reaction
4. the lower E_act, the greater the number of productive collisions, and the faster reaction
Catalysis by enzymes:
1. an enzyme decreases the time it takes for the reaction to reach equilibrium by lowering its activation energy
2. to be active, an enzyme may require a metal ion, a coenzyme, or both
3. most enzymes denature and lose their catalytic activity above 323-333K (50-60°C)
4. most enzymes have their maximum activity between the pH values of 5-9
Coagulation:
1. of hydrophilic colloid is irreversible
2. of hydrophilic colloid takes place when water coat has been removed
3. of hydrophobic colloids is reversible
4. of hydrophobic colloids takes place when electrical charge present on the surface becomes neutralized
Most of the water in the human body is found:
1. in blood plasma.
2. Inside cells.
3. as interstitial fluids.
4. in miscellaneous fluids, such as cerebrospinal fluid and lymph.
5. none of the above.
The major cation and anion inside cells are________and_______, respectively.
1. potassium; chloride
2. potassium; hydrogen phosphate
3. sodium; hydrogen carbonate
4. sodium; chloride
5. sodium; hydrogen phosphate
The osmolarities of blood plasma, intracellular fluid, and interstitial fluid are_____because_____.
1. the same; their compositions are identical
2. the same; they contain the same total number but different kinds of dissolved particles
3. different; they contain the same kinds and proportions of dissolved particles but different total numbers of particles
4. different; osmosis cannot occur fast enough to balance the differences
5. different; each fluid contains different numbers of each kind of solute particles
If the concentration of OH- in an aqueous solution is 1.4 x 10-7 M, the concentration of H3O+ is:
1. 7.1 x 10+6 M.
2. 1.0 x 10-7 M.
3. 1.4 x 10-7 M.
4. 7.1 x 10-8 M.
5. 1.3 x 10-8 M.
Phosphate buffer in human organism:
1. works in connection with pulmonary regulation
2. Is the major extracellular buffer system
3. the optimal pH for this buffer is 7.4
4. in phosphate buffer in urine (pH about 6,0) ratio of hydrogen phosphate to dihydrogen phosphate is 1/4
The water molecule has a ________ geometry because its central atom has_____bond and_____ lone pairs of electrons.
1. bent; two; two
2. linear; two; two
3. pyramidal; three; one
4. tetrahedral; four; zero
5. planar triangular; three; one
A chemical bond formed when two atoms share two pairs of electrons is a _______bond; it is best described as________?
1. double; covalent
2. double; ionic
3. single; covalent
4. single; ionic
5. triple; covalent
A chemical bond formed when two atoms share one pair of electrons is a_________bond; it is best described as
1. double; covalent
2. double; ionic
3. single; covalent
4. single; ionic
5. triple; covalent
The classification of an acid or a base as weak or strong is determined by
1. the solubility of the acid or base.
2. the extent of dissociation of the dissolved acid or base.
3. the concentrations of the acid or base.
4. more than one choice is correct.
All of the following are fun
1. defense from foreign organisms.
2. transport of waste products.
3. regulation of body temperature.
4. production of energy for anabolic processes.
5. regulation of acid-base balance in the body.
An increase in blood pH due to increased loss of CO2 through hyperventilation is called
1. respiratory acidosis.
2. respiratory alkalosis.
3. metabolic acidosis.
4. metabolic alkalosis.
5. diabetic ketosis.
Free-energy change (ΔG):
1. tells whether a reaction can occur and how fast the reaction will occur
2. the value of ΔG for the reverse of a reaction is numerically equal to the value of ΔG for the forward reaction but has the opposite sign
3. a positive value for ΔG means that free energy is released and the reaction or process is spontaneous
4. a negative value for ΔG means that free energy must be added and the process is nonspontaneous
Choose true sentences:
1. colloids are not dialyzed
2. emulsions have hydrophobic character and are also called suspensions or irreversible colloids
3. colloids show permanent Brownian motions
4. colloids show Tyndall effect
5. proteins are easiest to be salted out in their isoelectric point (pl)
Free radicals:
1. are atoms or molecules with one or more unpaired electron in its outer shell
2. are usually very reactive and can react with other atoms very quickly
3. are highly unstable molecules that have electrons available to react with various organic substrates
4. include molecules such as singlet oxygen and ozone
Hydrophobic colloids:
1. are mostly built by oxides, sulphates, hydroxides of heavy metals
2. are built usually by large molecules such as proteins
3. their stability is due to the presence of water molecules adsorbed on their surface
4. their stability is due to large quantities of one type of ions adsorbed on their surface
The composition of blood plasma and interstitial fluid are almost identical, except that
interstitial fluid contains__________than blood plasma.
1. more water
2. less water
3. more proteins
4. fewer proteins
5. more phosphate
Which bodily fluid has the highest concentration of potassium ion?
1. intracellular fluid
2. extracellular fluid
3. blood plasma
4. blood serum
5. none of the above
If "A" contains 2% NaCl and is separated by a semipermeable membrane from "B" which contains 10% NaCl, which event will occur?
1. NaCl will flow from "A" to "B".
2. NaCl will flow from "B" to "A".
3. Water will flow from "A" to "B".
4. Water will flow from "B" to "A".
5. none of the above
From Henderson-Hasselbalch equation it follows that:
1. The calculation of the pH value of the buffer mixture is possible when the concentrations of the buffer components are given
2. The pH of the buffer mixture depends only on the nature of the acid comprised in it (pka)
3. The pH of the buffer mixture decreases with dilution of the buffer and increases with concentration of the buffer
4. when the concentrations of the buffer components are the same then pH = pka