Physical Properties Vs Chemical Properties Quiz Chapter 2
Questions and Answers
- 1.
The atomic weight is only an average of relative weights of an atom and its isotopes, and it may vary from the weight of a specific isotope.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The explanation for the given correct answer is that the atomic weight is indeed an average of the relative weights of an atom and its isotopes. Isotopes are atoms of the same element that have different numbers of neutrons, resulting in different atomic weights. Therefore, the atomic weight listed on the periodic table is an average value that takes into account the abundance of each isotope. As a result, the atomic weight may vary from the weight of a specific isotope.Rate this question:
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- 2.
Emulsions and colloids are the same thing.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Emulsions and colloids are not the same thing. While both involve the dispersion of one substance within another, there is a distinction between the two. Emulsions refer specifically to the dispersion of immiscible liquids, such as oil and water, where one liquid is dispersed as droplets within the other. Colloids, on the other hand, can involve the dispersion of various substances, such as solid particles or liquid droplets, within a different medium. Therefore, the statement that emulsions and colloids are the same thing is incorrect.Rate this question:
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- 3.
Chemical properties are determined primarily by neutrons.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
This statement is false. Chemical properties are primarily determined by the arrangement and behavior of electrons in an atom, not by neutrons. Neutrons are subatomic particles that contribute to the mass of an atom but do not directly influence its chemical properties. The number of protons, which determines the element's identity, and the arrangement of electrons in the outermost energy level are the main factors that determine an atom's chemical properties.Rate this question:
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- 4.
A charged particle is generally called an ion.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
A charged particle is indeed generally called an ion. An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a positive or negative charge. This means that ions are charged particles, and they can be formed through various processes such as chemical reactions or the gain/loss of electrons in an electric field. Therefore, the statement "A charged particle is generally called an ion" is true.Rate this question:
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- 5.
Isotopes differ from each other only in the number of electrons contained.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. They have the same number of electrons because the number of electrons in an atom is determined by the number of protons. Therefore, the statement that isotopes differ from each other only in the number of electrons contained is false.Rate this question:
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- 6.
About 60 to 80% of the volume of most living cells consists of organic compounds.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement that about 60 to 80% of the volume of most living cells consists of organic compounds is false. While organic compounds are important for cellular function, they do not make up such a large percentage of the cell's volume. The majority of a cell's volume is actually occupied by water, which makes up about 70-90% of the cell's total volume. Organic compounds, such as proteins, lipids, and nucleic acids, are present in smaller quantities within the cell.Rate this question:
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- 7.
Lipids are a poor source of stored energy.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Lipids are actually a rich source of stored energy. They contain more than twice the amount of energy per gram compared to carbohydrates or proteins. When the body needs energy, it can break down lipids and release this stored energy.Rate this question:
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- 8.
Current information theorizes that Omega-3 fatty acids decrease the risk of heart disease.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Omega-3 fatty acids have been extensively studied and research suggests that they can indeed decrease the risk of heart disease. These essential fatty acids have been shown to reduce inflammation, lower blood pressure, decrease triglyceride levels, and improve overall heart health. They can also help prevent the formation of blood clots, which can lead to heart attacks. Therefore, the statement that Omega-3 fatty acids decrease the risk of heart disease is true based on current information and research.Rate this question:
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- 9.
Glucose is an example of a monosaccharide.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Glucose is indeed an example of a monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar molecule. Glucose is a six-carbon sugar that is commonly found in fruits, honey, and the bloodstream of animals. It is an essential source of energy for living organisms and is used in cellular respiration to produce ATP. Therefore, the statement "Glucose is an example of a monosaccharide" is true.Rate this question:
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- 10.
A molecule consisting of one carbon atom and two oxygen atoms is correctly written as CO2.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The molecule consisting of one carbon atom and two oxygen atoms is correctly written as CO2 because the chemical formula for carbon dioxide is CO2. In this formula, the carbon atom is represented by the symbol C and the oxygen atoms are represented by the symbol O. The subscript 2 indicates that there are two oxygen atoms present in the molecule.Rate this question:
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- 11.
The lower the pH, the higher the hydrogen ion concentration.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because pH is a measure of the concentration of hydrogen ions in a solution. A lower pH indicates a higher concentration of hydrogen ions, while a higher pH indicates a lower concentration of hydrogen ions. Therefore, the lower the pH, the higher the hydrogen ion concentration.Rate this question:
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- 12.
Covalent bonds are generally less stable than ionic bonds.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Covalent bonds are generally more stable than ionic bonds. In a covalent bond, two atoms share electrons, creating a strong bond. This sharing of electrons allows both atoms to achieve a stable electron configuration. On the other hand, in an ionic bond, one atom donates electrons to another atom, creating a bond through the attraction of opposite charges. This type of bond is generally weaker and more easily broken. Therefore, the statement that covalent bonds are generally less stable than ionic bonds is false.Rate this question:
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- 13.
Hydrogen bonds are comparatively strong bonds.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Hydrogen bonds are not comparatively strong bonds. In fact, they are weaker than covalent or ionic bonds. Hydrogen bonds occur when a hydrogen atom is attracted to an electronegative atom, such as oxygen or nitrogen. While they are important in many biological processes, such as the structure of DNA and protein folding, hydrogen bonds are relatively weak and can be easily broken.Rate this question:
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- 14.
The fact that no chemical bonding occurs between the components of a mixture is the chief difference between mixtures and compounds.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The explanation for the given correct answer is that mixtures are composed of two or more substances that are physically combined, but they do not undergo any chemical reactions or bonding. On the other hand, compounds are formed when two or more elements chemically combine and form new substances with different properties. Therefore, the absence of chemical bonding between the components of a mixture is indeed the main difference between mixtures and compounds, making the statement true.Rate this question:
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- 15.
Alpha particles, although relatively weak energy particles, are second only to smoking as a cause of lung cancer.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Alpha particles are indeed a cause of lung cancer, second only to smoking. Despite being weak energy particles, they can cause significant damage to the cells in the lungs if inhaled. This damage can lead to the development of cancer over time. Therefore, the statement that alpha particles are second only to smoking as a cause of lung cancer is true.Rate this question:
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- 16.
No chemical bonding occurs between the components of a mixture.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Chemical bonding refers to the process of atoms or molecules combining to form new substances. In a mixture, the components are simply physically mixed together and can be separated without undergoing any chemical changes. Therefore, no chemical bonding occurs between the components of a mixture.Rate this question:
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- 17.
All organic compounds contain carbon.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
This statement is true because organic compounds are defined as compounds that contain carbon atoms. Carbon is the key element in organic chemistry and is the basis for the structure and properties of organic compounds. Therefore, all organic compounds must contain carbon.Rate this question:
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- 18.
A dipeptide can be broken into two amino acids by dehydration synthesis.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
A dipeptide is formed by the dehydration synthesis of two amino acids, not broken down. Dehydration synthesis is a chemical reaction that combines molecules by removing water, while hydrolysis is the process of breaking down molecules by adding water. Therefore, the statement that a dipeptide can be broken into two amino acids by dehydration synthesis is false.Rate this question:
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- 19.
Which of the following is necessary for proper conduction of nervous impulses?
- A.
Fe
- B.
I
- C.
P
- D.
Na
Correct Answer
D. NaExplanation
Sodium (Na) is necessary for proper conduction of nervous impulses. Nervous impulses are electrical signals that travel along nerve cells, and sodium ions play a crucial role in this process. When a nerve impulse is generated, sodium channels open in the cell membrane, allowing sodium ions to enter the cell. This influx of sodium ions creates a positive charge inside the cell, which triggers the propagation of the nerve impulse along the nerve fiber. Without sodium, the conduction of nerve impulses would be impaired, leading to communication breakdown within the nervous system.Rate this question:
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- 20.
A phospholipid is usually ________.
- A.
Partially polar and partially nonpolar
- B.
Completely nonpolar
- C.
Completely polar
- D.
Neither polar nor nonpolar
Correct Answer
A. Partially polar and partially nonpolarExplanation
A phospholipid is usually partially polar and partially nonpolar because it consists of a hydrophilic (polar) head and a hydrophobic (nonpolar) tail. The head is composed of a phosphate group and glycerol, which are polar molecules, while the tail is made up of fatty acid chains, which are nonpolar. This unique structure allows phospholipids to form the lipid bilayer of cell membranes, with the polar heads facing the aqueous environment and the nonpolar tails facing each other.Rate this question:
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- 21.
In general, the category of lipids that we refer to as oils have ________.
- A.
A high water content
- B.
Long fatty acid chains
- C.
A high degree of saturated bonds
- D.
A high degree of unsaturated bonds
Correct Answer
D. A high degree of unsaturated bondsExplanation
Oils are a category of lipids that are typically liquid at room temperature. This characteristic is due to the presence of a high degree of unsaturated bonds in their structure. Unsaturated bonds refer to double or triple bonds between carbon atoms, which cause the molecules to have a bent or kinked shape. This prevents the lipids from packing tightly together, resulting in a liquid consistency.Rate this question:
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- 22.
The genetic information is coded in DNA by ________.
- A.
The regular alteration of sugar and phosphate molecules
- B.
The sequence of the nucleotides
- C.
The three-dimensional structure of the double helix
- D.
The arrangement of the histones
Correct Answer
B. The sequence of the nucleotidesExplanation
The genetic information is coded in DNA by the sequence of the nucleotides. This means that the specific order of the four nucleotide bases (adenine, thymine, cytosine, and guanine) in a DNA molecule determines the genetic instructions for building and functioning of an organism. The sequence of nucleotides forms the genetic code that carries the instructions for protein synthesis and other cellular processes. The regular alteration of sugar and phosphate molecules, the three-dimensional structure of the double helix, and the arrangement of the histones are important aspects of DNA structure and packaging, but they do not directly determine the genetic information.Rate this question:
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- 23.
Which of the following is not true of proteins?
- A.
They may be denatured or coagulated by heat or acidity.
- B.
Some types are called enzymes.
- C.
They appear to be the molecular carriers of the coded hereditary information.
- D.
Their function depends on the three-dimensional shape.
Correct Answer
C. They appear to be the molecular carriers of the coded hereditary information.Explanation
Proteins are not the molecular carriers of the coded hereditary information. This role is carried out by nucleic acids, specifically DNA and RNA. Proteins, on the other hand, have a variety of functions in the body, including structural support, enzymatic activity, and transportation of molecules. They can be denatured or coagulated by heat or acidity, some types are called enzymes, and their function depends on their three-dimensional shape.Rate this question:
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- 24.
The single most abundant protein in the body is ________.
- A.
DNA
- B.
Hemoglobin
- C.
Collagen
- D.
Glucose
Correct Answer
C. CollagenExplanation
Collagen is the correct answer because it is the most abundant protein in the body. It is found in various connective tissues such as skin, bones, tendons, and cartilage. Collagen provides structural support to these tissues and helps maintain their strength and elasticity. It also plays a crucial role in wound healing and maintaining the health of the skin. DNA, hemoglobin, and glucose are not proteins and therefore cannot be the most abundant protein in the body.Rate this question:
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- 25.
Carbohydrates are stored in the liver and muscles in the form of ________.
- A.
Glucose
- B.
Triglycerides
- C.
Glycogen
- D.
Cholesterol
Correct Answer
C. GlycogenExplanation
Carbohydrates are stored in the liver and muscles in the form of glycogen. Glycogen is a polysaccharide that serves as a storage form of glucose in the body. It is synthesized and stored when blood glucose levels are high, and it can be broken down into glucose when blood glucose levels drop, providing a quick source of energy for the body. Triglycerides are the storage form of fats, not carbohydrates. Glucose is a simple sugar and a component of glycogen, but it is not the storage form itself. Cholesterol is a type of lipid and is not involved in carbohydrate storage.Rate this question:
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- 26.
Coenzymes are ________.
- A.
Organic molecules derived from vitamins
- B.
Two enzymes that perform the same function
- C.
Metal ions
- D.
Enzymes that work together
Correct Answer
A. Organic molecules derived from vitaminsExplanation
Coenzymes are organic molecules derived from vitamins. They are essential for the proper functioning of enzymes, as they assist enzymes in carrying out various biochemical reactions in the body. Coenzymes act as temporary carriers of atoms or functional groups during these reactions, allowing enzymes to catalyze the conversion of substrates into products. Without coenzymes, many enzymatic reactions would not occur efficiently, leading to disruptions in cellular processes. Therefore, coenzymes play a crucial role in maintaining overall metabolic and physiological functions in organisms.Rate this question:
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- 27.
The speed or rate of a chemical reaction is influenced by all of the following except ________.
- A.
The concentration of the reactants
- B.
The temperature
- C.
The presence of catalysts or enzymes
- D.
The presence or absence of carbon
Correct Answer
D. The presence or absence of carbonExplanation
The speed or rate of a chemical reaction is influenced by several factors, including the concentration of the reactants, the temperature, and the presence of catalysts or enzymes. However, the presence or absence of carbon does not directly affect the speed or rate of a chemical reaction. Carbon is an element that is commonly found in organic compounds, but its presence or absence does not have a direct impact on the reaction rate. Therefore, the correct answer is the presence or absence of carbon.Rate this question:
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- 28.
A chemical reaction in which bonds are broken is usually associated with ________.
- A.
The release of energy
- B.
The consumption of energy
- C.
A synthesis
- D.
Forming a larger molecule
Correct Answer
A. The release of energyExplanation
A chemical reaction in which bonds are broken is usually associated with the release of energy. When bonds are broken, the potential energy stored in those bonds is converted into kinetic energy, resulting in the release of energy. This energy can be in the form of heat, light, or sound, depending on the specific reaction. The release of energy is a characteristic of exothermic reactions, where the overall energy of the system decreases.Rate this question:
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- 29.
Salts are always ________.
- A.
Ionic compounds
- B.
Single covalent compounds
- C.
Double covalent compounds
- D.
Hydrogen bonded
Correct Answer
A. Ionic compoundsExplanation
Salts are always ionic compounds because they are formed when a metal donates electrons to a non-metal, resulting in the formation of positive and negative ions. These ions are held together by strong electrostatic forces of attraction, creating a crystal lattice structure. This ionic bonding gives salts their characteristic properties such as high melting and boiling points, solubility in water, and ability to conduct electricity when dissolved or melted.Rate this question:
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- 30.
The numbers listed represent the first, second, and third energy levels, respectively. On this basis, which of the following is an unstable or reactive atom?
- A.
2, 8, 8
- B.
2, 8
- C.
2
- D.
2, 8, 1
Correct Answer
D. 2, 8, 1Explanation
An atom with the electron configuration 2, 8, 1 is considered unstable or reactive because it has an incomplete outermost energy level. The outermost energy level is the valence shell, and atoms tend to be more stable when their valence shell is filled. In this case, the atom has only one electron in its valence shell, which means it is likely to react with other atoms in order to gain or lose electrons and achieve a full valence shell.Rate this question:
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- 31.
A solution that has a pH of 2 could best be described as being ________.
- A.
Acidic
- B.
Basic
- C.
Neutral
- D.
Slightly acidic
Correct Answer
A. AcidicExplanation
A solution with a pH of 2 indicates a high concentration of hydrogen ions, making it acidic. The lower the pH value, the higher the acidity of the solution. In this case, the pH of 2 suggests a strong acid.Rate this question:
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- 32.
Which of the following is the major positive ion outside cells?
- A.
Nitrogen
- B.
Hydrogen
- C.
Potassium
- D.
Sodium
Correct Answer
D. SodiumExplanation
Sodium is the major positive ion outside cells. This is because sodium ions are more concentrated outside the cell compared to inside, creating an electrochemical gradient. This gradient allows sodium ions to move into the cell through specific channels, which is important for various cellular processes such as nerve impulse transmission and muscle contraction.Rate this question:
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- 33.
Which of the following would be regarded as an organic molecule?
- A.
H2O
- B.
NaCl
- C.
NaOH
- D.
CH4
Correct Answer
D. CH4Explanation
CH4, also known as methane, would be regarded as an organic molecule because it contains carbon, which is a key characteristic of organic compounds. Organic molecules are compounds that contain carbon atoms bonded to hydrogen atoms, and methane fits this definition. H2O, NaCl, and NaOH do not contain carbon and are therefore not organic molecules.Rate this question:
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- 34.
A chain of 25 amino acids would be called a ________.
- A.
Polypeptide
- B.
Nucleotide
- C.
Protein
- D.
Starch
Correct Answer
A. PolypeptideExplanation
A chain of 25 amino acids is called a polypeptide. A polypeptide is a long chain of amino acids that are linked together by peptide bonds. It is a precursor to a protein and can fold into a specific three-dimensional structure to perform its biological function.Rate this question:
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- 35.
A long chain of simple sugars would be a __________.
- A.
Monosaccharide
- B.
Polysaccharide
- C.
Protein
- D.
Nucleic acid
Correct Answer
B. PolysaccharideExplanation
A long chain of simple sugars would be a polysaccharide because polysaccharides are complex carbohydrates composed of multiple monosaccharide units linked together. This is in contrast to monosaccharides, which are single sugar molecules, and proteins and nucleic acids, which are different types of macromolecules.Rate this question:
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- 36.
The coiling of the protein chain backbone into an alpha helix is referred to as the ________.
- A.
Primary structure
- B.
Secondary structure
- C.
Tertiary structure
- D.
Quaternary structure
Correct Answer
B. Secondary structureExplanation
The coiling of the protein chain backbone into an alpha helix is referred to as the secondary structure. The secondary structure of a protein refers to the local folding patterns that occur within a specific region of the protein chain. In the case of an alpha helix, the backbone of the protein chain forms a tightly coiled structure resembling a spiral staircase. This secondary structure is stabilized by hydrogen bonds between the amino acid residues in the backbone. The secondary structure is one of the key elements that contribute to the overall three-dimensional structure and function of a protein.Rate this question:
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- 37.
Carbohydrates and proteins are built up from their basic building blocks by the ________.
- A.
Addition of a water molecule between each two units
- B.
Addition of a carbon atom between each two units
- C.
Removal of a water molecule between each two units
- D.
Removal of a nitrogen atom between each two units
Correct Answer
C. Removal of a water molecule between each two unitsExplanation
Carbohydrates and proteins are built up from their basic building blocks by the removal of a water molecule between each two units. This process is known as dehydration synthesis or condensation reaction. In this reaction, a hydroxyl group (-OH) from one unit and a hydrogen atom (-H) from another unit combine to form a water molecule, which is then removed. This reaction allows for the formation of a covalent bond between the two units, resulting in the formation of a larger molecule.Rate this question:
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- 38.
Which statement about enzymes is false?
- A.
Enzymes raise the activation energy needed to start a reaction.
- B.
Enzymes are composed mostly of protein.
- C.
Enzymes are organic catalysts.
- D.
Enzymes may be damaged by high temperature.
Correct Answer
A. Enzymes raise the activation energy needed to start a reaction.Explanation
Enzymes are actually known to lower the activation energy needed to start a reaction, not raise it. This is one of the main functions of enzymes - to speed up chemical reactions by reducing the energy barrier required for the reaction to occur.Rate this question:
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- 39.
Many plasma proteins may function as _________.
- A.
Antibodies
- B.
Structural proteins
- C.
Buffers
- D.
Oxygen transport vesicles
Correct Answer
C. BuffersExplanation
Plasma proteins can act as buffers because they have the ability to accept or donate hydrogen ions, helping to maintain the pH balance in the blood. This is important for various physiological processes to function properly.Rate this question:
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- 40.
Which of the following is true regarding the concentration of solutions?
- A.
Percent solutions are parts per 1000 parts.
- B.
Molarity is one mole of solute per 1000 ml of solution.
- C.
To calculate molarity, one must know the atomic number of the solute.
- D.
To calculate molarity, one must know the atomic weight of the solvent.
Correct Answer
B. Molarity is one mole of solute per 1000 ml of solution.Explanation
Molarity is a unit of concentration that represents the number of moles of solute per liter of solution. In this case, it is stated that molarity is one mole of solute per 1000 ml of solution. This means that for every 1000 ml of solution, there is one mole of solute present.Rate this question:
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- 41.
Select the statement about mixtures that is correct.
- A.
A solution contains solvent in large amounts and solute in smaller quantities.
- B.
Solutions contain particles that settle out in time.
- C.
Suspensions can change reversibly from liquid to solid.
- D.
Suspensions are homogeneous mixtures of two or more components.
Correct Answer
A. A solution contains solvent in large amounts and solute in smaller quantities.Explanation
A solution is a homogeneous mixture where the solvent is present in larger amounts than the solute. This means that the solvent is the substance that is present in greater quantity and dissolves the solute, which is present in smaller quantities.Rate this question:
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- 42.
HCO3- is _________.
- A.
A bicarbonate ion
- B.
Common in the liver
- C.
A weak acid
- D.
A proton donor
Correct Answer
A. A bicarbonate ionExplanation
HCO3- refers to bicarbonate ion, which is a negatively charged molecule made up of one carbon atom and three oxygen atoms. It is commonly found in the body, particularly in the blood and acts as a buffer to maintain the pH balance. Bicarbonate ion can act as a weak acid, donating a proton (H+) in certain chemical reactions. Therefore, the correct answer is "a bicarbonate ion".Rate this question:
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- 43.
Select which reactions will usually be irreversible regarding chemical equilibrium in living systems.
- A.
Glucose to CO2 & H2O
- B.
ADP + Pi to make ATP
- C.
H2O + CO2 to make H2CO3
- D.
Molecules joined to make glycogen
Correct Answer
A. Glucose to CO2 & H2OExplanation
In living systems, the reaction of glucose to CO2 and H2O is usually irreversible because it is part of the process of cellular respiration, where glucose is broken down to produce energy in the form of ATP. This reaction is necessary for the survival and functioning of living organisms. On the other hand, the other reactions mentioned, such as ADP + Pi to make ATP, H2O + CO2 to make H2CO3, and molecules joined to make glycogen, can be reversible depending on the cellular conditions and metabolic needs.Rate this question:
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- 44.
In redox reactions ________.
- A.
Both decomposition and electron exchange occur
- B.
The electron acceptor is oxidized
- C.
The electron donor is reduced
- D.
The reaction is always easily reversible
Correct Answer
A. Both decomposition and electron exchange occurExplanation
In redox reactions, both decomposition and electron exchange occur. This means that the reactants break down into simpler substances, and at the same time, there is a transfer of electrons between the reactants. The electron acceptor is oxidized, meaning it loses electrons, while the electron donor is reduced, meaning it gains electrons. This process allows for the transfer of energy and the formation of new compounds. The reaction may or may not be easily reversible, depending on the specific redox reaction.Rate this question:
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- 45.
Fibrous proteins ________.
- A.
Rarely exhibit secondary structure
- B.
Are very stable and insoluble in water
- C.
Are usually called enzymes
- D.
Are cellular catalysts
Correct Answer
B. Are very stable and insoluble in waterExplanation
Fibrous proteins are known for their stability and insolubility in water. This is because they have a highly ordered and repetitive structure, which allows them to form strong and stable interactions with each other. These proteins are often found in structural components of cells and tissues, such as collagen in connective tissues and keratin in hair and nails. Their stability and insolubility in water make them suitable for providing strength and support to these structures.Rate this question:
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- 46.
The ATP molecule is not used in ___________.
- A.
Chemical work
- B.
Mechanical work
- C.
Transport
- D.
Pigments
Correct Answer
D. PigmentsExplanation
ATP (adenosine triphosphate) is a molecule that provides energy for cellular processes. It is commonly used in chemical work, such as synthesis of molecules, and mechanical work, such as muscle contraction. ATP is also involved in transport processes, such as the movement of ions and molecules across cell membranes. However, it is not directly involved in the production or function of pigments, which are responsible for the coloration of organisms.Rate this question:
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- 47.
Select the most correct statement regarding nucleic acids.
- A.
Three forms exist: DNA, RNA, and tDNA.
- B.
DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
- C.
RNA is a long, single-stranded molecule made up of the bases A, T, G, and C.
- D.
TDNA is considered a molecular slave of DNA.
Correct Answer
B. DNA is a long, double-stranded molecule made up of A, T, G, and C bases.Explanation
The correct answer is DNA is a long, double-stranded molecule made up of A, T, G, and C bases. This statement accurately describes the structure and composition of DNA, which is a double helix made up of nucleotides containing the bases adenine (A), thymine (T), guanine (G), and cytosine (C). RNA, on the other hand, is a single-stranded molecule and tDNA is not a recognized form of nucleic acid.Rate this question:
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- 48.
________ is a suspension.
- A.
Cytoplasm
- B.
Saltwater
- C.
Rubbing alcohol
- D.
Blood
Correct Answer
D. BloodExplanation
Blood is a suspension because it is a mixture of different components that are not chemically bonded together. It consists of red and white blood cells, platelets, and plasma, which are all suspended in the liquid medium. This suspension allows for the movement and transport of various substances, such as oxygen, nutrients, and waste products, throughout the body.Rate this question:
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- 49.
Select the correct statement about isotopes.
- A.
Isotopes of the same element have the same atomic number but differ in their atomic mass.
- B.
All the isotopes of an element have the same number of neutrons.
- C.
All the isotopes of an element are radioactive.
- D.
Isotopes occur only in the heavier elements.
Correct Answer
A. Isotopes of the same element have the same atomic number but differ in their atomic mass.Explanation
Isotopes are atoms of the same element that have the same number of protons (atomic number) but differ in their number of neutrons, resulting in different atomic masses. This means that isotopes have the same chemical properties but may have different physical properties due to their varying atomic masses. This statement accurately describes the nature of isotopes.Rate this question:
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- 50.
The four elements that make up about 96% of body matter are ________.
- A.
Carbon, oxygen, phosphorus, calcium
- B.
Nitrogen, hydrogen, calcium, sodium
- C.
Carbon, oxygen, hydrogen, nitrogen
- D.
Sodium, potassium, hydrogen, oxygen
Correct Answer
C. Carbon, oxygen, hydrogen, nitrogenExplanation
The four elements that make up about 96% of body matter are carbon, oxygen, hydrogen, and nitrogen. These elements are essential for the formation of molecules such as carbohydrates, lipids, proteins, and nucleic acids, which are the building blocks of life. Carbon provides the backbone for organic compounds, oxygen is necessary for respiration, hydrogen is involved in bonding and energy transfer, and nitrogen is a crucial component of proteins and nucleic acids. Together, these elements play a vital role in maintaining the structure and function of living organisms.Rate this question:
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