chm
Which of the following is an aromatic molecule? Check all that apply.
1 diamond with 3 lines within 1 diamond with 2 lines within and one without in a circle
How many electrons are gained or lost in the following half-reaction? Na → Na+ Express your answer using one significant figure.
1 electron(s)
In an enzyme-catalyzed reaction, the reactant species to which the enzyme binds is called the substrate. The substrate is then converted into products by a series of steps. The lock-and-key model explains the steps involved in an enzyme-catalyzed reaction. Label the following diagram that illustrates the lock-and-key model of enzyme activity. Drag the appropriate labels to their respective targets.
1. active site (right zig zag side of enzyme), 2. enzyme-substrate complex (when enzyme and substrate connect), 3 Enzyme + Products
Correctly identify the following functional groups in this organic molecule-amide, ester, ketone, ether, alcohol, aldehyde, amine. 1 = ether, 3 = ester, 6 = aldehyde, 9 = alcohol 2 = amide, 6 = aldehyde, 7 = amine, 8 = ether 2 = amide, 4 = ester, 7 = amine, 8 = ether 1 = ester, 5 = alcohol, 8 = ether, 9 = ketone
2 = amide, 6 = aldehyde, 7 = amine, 8 = ether
Which of the following is a saturated molecule? Check all that apply.
2 diamonds with one side missing
How many electrons are gained or lost in the following half-reaction? 2 Na → 2 Na+ Express your answer as an integer.
2 electron(s)
How many electrons are gained or lost in the following half-reactions? Zn → Zn2+ How many electrons are gained or lost in the following half-reactions? Zn → Zn2+ 2 electrons are gained 2 electrons are lost 1/2 electron is gained 1/2 electron is lost 4 electrons are gained
2 electrons are lost
Which of the following does not contain a double bond? Check all that apply.
2 full diamonds
Which of the following does not contain a double bond? Check all that apply.
2 full normal diamonds with no sides missing, no lines within
Chemical equations need to be balanced not only in terms of the number of atoms, but also by the charge. In other words, just as there should be the same number of atoms before and after the arrow of an equation, there should be the same charge. What set of coefficients is necessary to balance the following chemical equation? ____ Ce4+ + ____ Cl- → ____ Ce3+ + ____ Cl2 Express your answer as a chemical equation.
2Ce4++2Cl−→2Ce3++Cl2
If an alcoholic beverage is 20 percent alcohol by volume, what is its proof? Express your answer using two significant figures.
40 proof
If an alcoholic beverage has a proof of 151, what is the percentage of alcohol in the beverage?
75.5 %
Starting with the partially balanced equation, CH3COOH(l)+?O2(g)→2CO2(g)+2H2O(l) what coefficient should be placed in front of O2 to balance the oxygen atoms? Express your answer numerically as an integer.
? = 2
Starting with the partially balanced equation, CH3COOH(l)+O2(g)→?CO2(g)+2H2O(l) what coefficient should be placed in front of CO2 to balance the carbon atoms? Express your answer numerically as an integer.
? = 2
Starting with the unbalanced equation for the combustion of ethanoic acid, CH3COOH(l)+O2(g)→CO2(g)+?H2O(l) what coefficient should be placed in front of H2O to balance the hydrogen atoms? Express your answer numerically as an integer.
? = 2
How are disaccharides and monosaccharides related? A disaccharide is composed of two monosaccharide units. Two different disaccharides are combined to form a monosaccharide. A disaccharide is composed of two of the same monosaccharide units. Two disaccharides are combined to form a monosaccharide. Two of the same disaccharides are combined to form a monosaccharide.
A disaccharide is composed of two monosaccharide units.
How are monomers and polymers related? A polymer is chemically identical to a monomer, only larger. A monomer is one strand of a polymer. A monomer is made when you condense a polymer through polymerization. A monomer is a small, repeating unit that makes up a polymer. none of the above
A monomer is a small, repeating unit that makes up a polymer.
Which of the following statements accurately describes amylose? Amylose is composed of polymeric amylose sugars. The amylose chain is not coiled. The amylose chain is highly branched. Amylose releases glucose at a slower rate than other starches. All of the above are untrue.
Amylose releases glucose at a slower rate than other starches.
Which of the following would be an example of a synergistic effect? Aspirin reduces fever and thins the blood. Penicillin kills infectious bacteria and beneficial bacteria in the intestine. Antidepressants and cold medicine together can lead to seizures. Caffeine suppresses the appetite and causes the jitters. none of the above
Antidepressants and cold medicine together can lead to seizures.
How are proteins similar to starch? Check all that apply. Both are polymers. Both are lipids. Both can be consumed and used as an energy source. Both are made of glucose monomers. Both are made of fructose monomers.
Both are polymers. Both can be consumed and used as an energy source.
Which of the following species is the reducing agent? 2 CuBr → 2Cu + Br2 CuBr Cu Cu+ Br- Br2
Br-
Which of the following molecules would probably be isolated closest to the bottom of a fractionating tower at a refinery? C8H18 C4H10 C40H82 C10H22 C20H42
C40H82
Which of the following molecules would probably be isolated closest to the top of a fractionating tower at a refinery? C40H82 C10H22 C8H18 C4H10 C20H42
C4H10
Which of the following is the simplest possible hydrocarbon? CH4 H2 C2H6 H2C=CH2 HC≡CH
CH4
Why might disposing of a lead-acid battery, nickel-cadmium battery or mercury battery in a landfill be a bad thing? Cadmium, mercury, and lead are all toxic metals and could leak out of the landfill. Cadmium, mercury, and lead are all very reactive and generate highly unstable compounds. Cadmium, mercury, and lead are all radioactive and release radiation. all of the above none of the above
Cadmium, mercury, and lead are all toxic metals and could leak out of the landfill.
Sometimes an individual going through a traumatic experience cannot stop hyperventilating. In such a circumstance, it is recommended that the individual breath into a paper bag or cupped hands as a useful way to avoid an increase in blood pH, which can cause the person to pass out. Explain how this works. Carbon dioxide initially exhaled is reinhaled to help maintain adequate levels of carbonic acid in the blood. The paper absorbs CO2 to prevent the accumulation of excess CO2 in the blood. The paper bag helps to retain the water vapor leaving the mouth to prevent an increase in the concentration of lactic acid in the body. It helps to slow their breathing down to prevent excess oxygen from entering the blood.
Carbon dioxide initially exhaled is reinhaled to help maintain adequate levels of carbonic acid in the blood.
Which of the following materials is most likely to act as an oxidizing agent? Which of the following materials is most likely to act as an oxidizing agent? Na+ Cl- Na Cl2 both Na and Na+
Cl2
Which of the following materials is most likely to undergo reduction? Cl- Na Na+ Cl2 both Na and Na+
Cl2
Are electrons gained or lost in the following half-reaction? Electrons are gained. Electrons are lost.
Electrons are lost.
Are electrons gained or lost in the following half-reaction? Are electrons gained or lost in the following half-reaction? Electrons are lost. Electrons are gained.
Electrons are lost.
Enzymes, which are proteins, play a crucial role in everyday life processes. Without enzymes, the digestion of food, such as carbohydrates, fats, and sugars, would take years to generate a usable amount of energy. Enzymes are best known as biological catalysts because they accelerate biochemical reactions. For example, pepsin, an enzyme, when released in the stomach helps in the digestion of proteins. An enzyme binds to a substrate (reactant) in a very specific manner, forming an enzyme-substrate complex. The enzyme-substrate complex then converts the substrate into the product. Once the reaction is complete, the product is released, and the enzyme is once again available to interact with new substrates. The enzyme is neither consumed nor changed after the reaction is complete. It is a catalyst that alters the reaction pathway and decreases the time required to form products. Enzymes are specific to one reaction or reaction type, and hence the mechanism by which enzymes work is known as the lock-and-key model of enzymes. According to this model, an enzyme has specific structural features that complement the reacting molecule or molecules. Part A Part complete Which of the following statements are true with respect to enzyme activity? Check all that apply. Enzymes affect the reaction pathway by forming an enzyme-substrate complex. The activation energy of a reaction increases when an enzyme is used to catalyze the reaction. Enzyme reactivity is not affected by change in pH and temperature. Enzymes speed up the reaction rate. Enzymes are regenerated when the reaction is completed.
Enzymes affect the reaction pathway by forming an enzyme-substrate complex. Enzymes speed up the reaction rate. Enzymes are regenerated when the reaction is completed.
Which equations are balanced? a) Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) b) 3Al (s) + 3 Br2 (l) → Al2Br3 (s) c) 2HgO (s) → 2 Hg (l) + O2 (g) Which equations are balanced? a) Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) b) 3Al (s) + 3 Br2 (l) → Al2Br3 (s) c) 2HgO (s) → 2 Hg (l) + O2 (g) Equations "b" and "c" are balanced. Only equation "c" is balanced. Equations "a" and "c" are balanced. All of them are balanced.
Equations "a" and "c" are balanced.
Why do ethers have lower boiling points than that of an alcohol of the same molecular weight? Ethers are more flammable and vaporize more easily. Ethers have higher boiling points than alcohols. Ethers do not have hydrogens. Ethers cannot hydrogen bond to other ethers. all of the above
Ethers cannot hydrogen bond to other ethers.
What is the primary difference between a fuel cell and a battery? Batteries can be recharged, fuel cells cannot. Fuel cells oxidize to supply electricity, batteries reduce to supply electricity. Fuel cells do not run down because they can be refueled; batteries run down and need to be recharged. Fuel cells do not use metals as oxidants and reductants, batteries have a static reservoir of oxidant and reductant. Batteries supply electricity; fuel cells supply heat.
Fuel cells do not run down because they can be refueled; batteries run down and need to be recharged.
For the following acid-base reaction, identify what is formed in the space marked. H2SO4 + KOH ↔ KHSO4 + ??? For the following acid-base reaction, identify what is formed in the space marked. H2SO4 + KOH ↔ KHSO4 + ??? KOH2SO4 H3OSO4 H2O K2SO4 none of the above
H2O
What is the main difference between High Density PolyEtyhlene (HDPE) and Low Density PolyEthylene(LDPE)? HDPE has very long chains packed close together; LDPE has long chains that are branched and do not pack together well. One is made from high density ethylene, the other from low density ethylene. HDPE has very long chains packed close together; LDPE has short chains that do not pack together well. LDPE is more useful than HDPE. HDPE is more useful than LDPE.
HDPE has very long chains packed close together; LDPE has long chains that are branched and do not pack together well.
How do inhibitors work to prevent an enzyme from functioning? Check all that apply. Inhibitors alter the receptor site. Inhibitors block the receptor site. Inhibitors bind to an enzyme. Inhibitors destroy an enzyme. all of the above none of the above
Inhibitors alter the receptor site. Inhibitors block the receptor site. Inhibitors bind to an enzyme.
How does chemotherapy work to fight a disease or infection? It exploits subtle differences between the host organism and the disease organism. It binds to receptor sites and boosts the immune system of the host organism. It binds to the DNA of the host organism preventing the disease from spreading. all of the above none of the above
It exploits subtle differences between the host organism and the disease organism.
What is a hydrocarbon? It is a wet carbon atom It is a molecule derived from hydrogen synthesis. It is any organic molecule. It is a molecule composed of carbon and hydrogen only. none of the above
It is a molecule composed of carbon and hydrogen only.
Why does starch begin to taste sweet after it has been in your mouth for a few minutes? Amylopectin from your saliva is breaking down the starch. It is a signal that digestion has begun and glucose units are being released. Glycogen is being released from the starch. Amylose from your saliva is breaking down the starch.
It is a signal that digestion has begun and glucose units are being released.
Why is oxygen usually an oxidizing agent? It does not undergo reduction. It is a very electronegative element. It likes to be oxidized. It is very abundant and so it is easier to react than nitrogen. all of the above
It is a very electronegative element.
Which of the following statements best describes monosaccharides? It is the fundamental unit of genetic material. It is the fundamental unit of life. It is the monomer of the sucrose polymer. It is the fundamental unit of a carbohydrate. It is the basic repeating unit of a polymer.
It is the fundamental unit of a carbohydrate.
Why does soap decrease the surface tension of of water? It keeps water molecules away from the surface. It decreases the amount of intermolecular attraction between the water molecules. It increases the capillary action of the water. It increases the ionic content of the water. none of the above
It keeps water molecules away from the surface.
What is the function of an antibiotic? It prevents the generation of viruses. It prevents the growth of bacteria. It punctures a bacterial cell wall. It prevents the growth of tumors. all of the above
It prevents the growth of bacteria.
How does fractional distillation work? It takes advantage of the different weight of molecules to separate them. It takes advantage of the different boiling points of molecules to separate them. It takes advantage of the different melting points to separate molecules. It uses the fraction of carbon in the isomers to separate the molecules. none of the above
It takes advantage of the different boiling points of molecules to separate them.
For the following acid-base reaction, identify what compound is formed in the space marked. HCl + KOH ↔ ???? + H2O KOH2 KCl KOH2Cl H3OCl none of the above
KCl
For the following acid-base reaction, identify what compound is formed in the space marked. HCl + KOH ↔ ???? + H2O For the following acid-base reaction, identify what compound is formed in the space marked. HCl + KOH ↔ ???? + H2O KCl H3OCl KOH2 KOH2Cl none of the above
KCl
What is one physical property that readily distinguishes lipids from other biological molecules? Lipids have very high melting points. Lipids are insoluble in water. Lipids are readily oxidized. Lipids form water soluble positive ions. none of the above
Lipids are insoluble in water.
What is the main structural feature that distinguishes lipids from other biomolecules? Lipids contain a large number of nonpolar, hydrophobic functional groups. Lipids form rigid, linear arrays of polymeric molecules that cannot be easily dissolved. Lipids contain a large number of hydrogen bonding functional groups. Lipids form coiled structures with extensive amounts of branching. none of the above
Lipids contain a large number of nonpolar, hydrophobic functional groups.
Which of the following statements about oxidation and reduction reactions is true? Which of the following statements about oxidation and reduction reactions is true? Only neutral atoms are formed in oxidation and reduction reactions. In a half-reaction, only half of an electron is transferred. More than one electron can be transferred in an oxidation and reduction reaction. A half-reaction is only used for reduction reactions. None of the above are true.
More than one electron can be transferred in an oxidation and reduction reaction.
Which of the following materials is most likely to undergo oxidation? Check all that apply. Cl- Na Cs K K+ Na+ Cl2
Na Cs K
For the following acid-base reaction, identify which salt is formed. HCl + NaOH ⇌ ???? + H2O Express your answer as a chemical formula.
NaCl
Which of the following is a heteroatom? Check all that apply. O N H S C
O N S
What is the main difference between the two forms of starch produced naturally? Both are the same but have different molecular weights. One is branched, the other is not. One is long and rigid, the other is not. One is coiled, the other is not. none of the above
One is branched, the other is not.
Which of the following is a correctly balanced equation? 4 P4 + 6 H2 → 4 PH3 2 P4 + 6 H2 → 8 PH3 P4 + 3 H2 → PH3 0 P4 + 6 H2 → 4 PH3 P4 + 6 H2 → 4 PH3
P4 + 6 H2 → 4 PH3
How are polysaccharides and polymers related? Polymers are condensed polysaccharides. Polysaccharides are made of individual polymers as monomers. Polysaccharides are polymers made of saccharide monomers. Polymers are only made by addition while polysaccharides are made by condensation. none of the above
Polysaccharides are polymers made of saccharide monomers.
Which of the following statements about polysaccharides are true? Check all that apply. Polysaccharides are insoluble. Polysaccharides are only composed of one type of monomeric unit. Polysaccharides contain hundreds of thousands of monosaccharide subunits. Polysaccharides are common sources of energy. All of the above are true. None of the above are true.
Polysaccharides contain hundreds of thousands of monosaccharide subunits. Polysaccharides are common sources of energy.
Which of the following materials is most likely to act as a reducing agent? Check all that apply. Check all that apply. Rb Cl2 Cl- F- Na+ Na K
Rb Na K
What is an obvious physical difference between saturated and unsaturated fats? Unsaturated fats are soluble in water while saturated fats are not. Saturated fats are soluble in water while unsaturated are not. Saturated fats burn cleaner than unsaturated fats. Saturated fats are usually solids while unsaturated fats are usually liquids. none of the above
Saturated fats are usually solids while unsaturated fats are usually liquids.
Which of the following statements accurately describes amylopectin? Amylopectin is composed of polymeric amylose sugars. The amylopectin chain is highly branched. The amylopectin chain is not coiled. Amylopectin produces glucose at a slower rate than other starches. All of the above are untrue.
The amylopectin chain is highly branched.
A chemical equation for the combustion of propane, C3H8, is shown below. Through this reaction is the carbon oxidized or reduced? C3H8 + 5 O2 → 3 CO2 + 4 H2O The carbon is reduced. The carbon is oxidized. Some of the carbons are oxidized while others are reduced. The carbon is neither oxidized nor reduced.
The carbon is oxidized.
How is cancer different from other diseases like viral or bacterial infections? Cancer cannot be transferred to other parts of the body. Cancer is more than one type of disease. The cells that cause cancer were once part of the body. The cancer cells do not have DNA or RNA. none of the above
The cells that cause cancer were once part of the body.
What is the main difference between condensation polymers and addition polymers? The number of atoms incorporated into the addition polymer increases compared to the starting monomers. The number of atoms incorporated into the condensation polymer increases compared to the starting monomers. Condensation polymers all lose water molecules when they form. The condensation polymer has less atoms in it than the sum of the starting monomers because a small molecule is lost during condensation. All of the above are true.
The condensation polymer has less atoms in it than the sum of the starting monomers because a small molecule is lost during condensation.
What is the major difference between nucleotides of deoxyribonuleic acid and ribonucleic acid? The ribose nucleic acid is missing a hydroxyl group on the nitrogenous base. The deoxyribose nucleic acid is missing a hydroxyl group on the sugar. Only the nitrogenous bases are different. The deoxyribose nucleic acid is missing a hydroxyl group on the nitrogenous base. The ribose nucleic acid is missing a hydroxyl group on the sugar.
The deoxyribose nucleic acid is missing a hydroxyl group on the sugar.
Is the food compartment in a refrigerator cooled by evaporation or condensation of the refrigerating coolant? Both evaporation and condensation of the refrigerating coolant cause the food compartment to cool. The food compartment of a refrigerator is cooled by evaporation of the refrigerating fluid because vaporization is a cooling process. It is neither the evaporation nor condensation of the refrigerating coolant that causes the food compartment to cool. Cooling is a matter of simple heat exchange via the refrigerator's motor. The food compartment of a refrigerator is cooled by condensation of the refrigerating fluid because condensation is a cooling process.
The food compartment of a refrigerator is cooled by evaporation of the refrigerating fluid because vaporization is a cooling process.
Why might coating a metal with another metal that is harder to oxidize prevent the first metal from being oxidized? All of the oxidizing agent is consumed using up the easily oxidized metal. It doesn't prevent it, but helps to slow it down. The metal that is acting as the coating is protected from moisture and oxygen. The metal that is coated is protected from moisture and oxygen so it doesn't react. all of the above
The metal that is coated is protected from moisture and oxygen so it doesn't react.
Why does a paper clip float when placed on water? The molecules of water hold together and keep it from sinking. It is less dense than water. It only floats on dense, cold water. It is lighter than water.
The molecules of water hold together and keep it from sinking.
What is the main difference between the sugars that make up starch and the sugars that make up cellulose? The sugars are completely different. The sugars are isomers of glucose but bonded in different orientations. The sugars form hydrogen bonds. The sugars are identical. Starch and cellulose are made of polysaccharides.
The sugars are isomers of glucose but bonded in different orientations.
What is the main tenet of the lock-and-key model for drug activity? There is a connection between molecular structure and its biological effect. The key to a drug's success is to keep it locked away from stomach acid. Only certain biological keys can unlock the potential of a drug. The biological lock of an enzyme can be activated by using certain chemical keys. all of the above
There is a connection between molecular structure and its biological effect.
What do all fats have in common? Check all that apply. They are all unsaturated molecules. They are all formed from glycerol. They are acidic. They have a high-energy content They all have identical hydrocarbon chains. all of the above
They are all formed from glycerol. They have a high-energy content
Which of the following statements describes most monosaccharides? They are composed of carbon, hydrogen and oxygen with each carbon bound to at least one oxygen. They are insoluble. They are considered to be unsaturated compounds. They are rarely found as monomers in nature. all of the above
They are composed of carbon, hydrogen and oxygen with each carbon bound to at least one oxygen.
What is unique about the polysaccharides that are involved in human digestion? They are composed of glucose only. They require lactase. They are composed of lactose only. They are simple carbohydrates. none of the above
They are composed of glucose only.
How are most hydrocarbons made? They are isolated from fossil fuels. They are made in swamps. They are made by plants. They are made at refineries. none of the above
They are isolated from fossil fuels.
How are carbohydrates usually produced in nature? They are made by the process of photosynthesis. They are extracted from the ground by plant roots. They are made by decomposition of sugars. They are generated in the decomposition of plants. none of the above
They are made by the process of photosynthesis.
Vitamins such as vitamin B and vitamin C are often lost by boiling vegetables. Why? They are fat-soluble compounds and vegetables do not have much fat. The heat of the boiling water destroys the vitamin. The heat of the boiling water causes the vitamin to evaporate. They are water soluble and are poured down the drain with the water. none of the above
They are water soluble and are poured down the drain with the water.
How do over-the-counter analgesics like aspirin work? They block nerve impulses. They block the production of pain-producing chemicals. They alter the perception of pain in the brain. all of the above none of the above
They block the production of pain-producing chemicals.
A great deal of heat is released when liquid water freezes. Why doesn't this heat simply remelt the ice? This heat is radiated outwards to the environment, rather than back into the ice. Once the water is in crystalline formation, it takes even more energy to melt it. There is not enough energy in the heat to melt ice. The heat is not concentrated enough to melt ice.
This heat is radiated outwards to the environment, rather than back into the ice.
Why is a permanent wave not really permanent? Disulfide bonds breaks and re-form every time you wash your hair. The chemicals used to treat the hair break down. Untreated new hair grows in to replace treated old hair. The keratin in the hair is no longer flexible.
Untreated new hair grows in to replace treated old hair.
Why are drops of water shaped like spheres? The interatomic forces are strongest for spherical shapes and so the molecules arrange into spheres. Water molecules are special and are the only molecules that form spheres. This is one of water's unique physical properties. Water molecules are composed of spheres and so the bulk material takes on the same shape. Water molecules at the surface are pulled into the liquid, making the drop as small as possible.
Water molecules at the surface are pulled into the liquid, making the drop as small as possible.
Why are drops of water shaped like spheres? Why are drops of water shaped like spheres? Water molecules at the surface are pulled into the liquid, making the drop as small as possible. Water molecules are composed of spheres and so the bulk material takes on the same shape. Water molecules are special and are the only molecules that form spheres. This is one of water's unique physical properties. The interatomic forces are strongest for spherical shapes and so the molecules arrange into spheres.
Water molecules at the surface are pulled into the liquid, making the drop as small as possible.
Given the following generic chemical reaction, which is the reactant? X → Y Given the following generic chemical reaction, which is the reactant? X → Y X is the reactant. Y is the reactant. → is the reactant. Both X and Y are the products. Both X and Y are the reactants.
X is the reactant.
Given the following generic chemical reaction, which is the product and which is the reactant? X → Y Check all that apply. X is the reactant. X is the product. Y is the product. → is the product. Both X and Y are the products. Both X and Y are the reactants.
X is the reactant. Y is the product.
Can a glass be filled to above its brim with water without the water spilling over the edge? No, it is just an optical illusion because water magnetizes things. Yes, due to the strong cohesive forces of gravity keeping the water in the cup. Yes, due to the strong adhesive forces between water molecules. Yes, due to the strong cohesive forces between water molecules.
Yes, due to the strong cohesive forces between water molecules.
What is the cause of lactose intolerance? Too much lactase is present in the intestine and it destroys the lactose. Lactose is poisonous and leads to illness. You cannot digest lactose but the bacteria in your intestine can and they produce a lot of gases in the process. The lactose is in competition with the lactase and it causes hydrogen production. none of the above
You cannot digest lactose but the bacteria in your intestine can and they produce a lot of gases in the process.
Why might increasing the concentration of a set of reactants increase the rate of reaction? Why might increasing the concentration of a set of reactants increase the rate of reaction? You have increased the chances that any two reactant molecules will collide and react. You have increased the ratio of reactants to products. The concentration of reactants is unrelated to the rate of reaction. The rate of reaction depends only on the mass of the atoms and therefore increases as you increase the mass of the reactants. none of the above
You have increased the chances that any two reactant molecules will collide and react.
Which of the following statements describes a neutral solution? [H3O+]/[OH-] = 1 [H3O+] × [OH-] ≠ 1 × 10-14 [H3O+]/[OH-] = 1 × 10-14 [H3O+] > [OH-] [H3O+] < [OH-]
[H3O+]/[OH-] = 1
X + Y → Z Which of the above reactions would proceed the fastest? a b c all proceed at same rate not enough information given
a box with most of both dots; fullest
Electrolysis is an example of ________. an exothermic reaction a chemical change a physical change an acid-base reaction
a chemical change
What is a pathogen? a type of virus that infects tobacco a disease-causing organism the side effect of a drug a type of receptor site specific to bacteria none of the above
a disease-causing organism
Fat molecules do not have ________. Check all that apply. a helium atom a carbon atom an oxygen atom a nitrogen atom a hydrogen atom
a helium atom a nitrogen atom
Which of the following is the hallmark of a saturated hydrocarbon? a hydrocarbon that is completely dissolved in water a hydrocarbon where carbon has only a single bond to two or more other carbons any molecule that is completely dissolved in a hydrocarbon solvent a hydrocarbon where carbon has multiple bonds to one or more other carbons none of the above
a hydrocarbon where carbon has only a single bond to two or more other carbons
Which of the following statements describes straight-chain hydrocarbon? a carbon atom that is bound straight to four hydrogens a hydrocarbon that has a linear rod shaped conformation a hydrocarbon where every carbon is bound with a straight line to every other carbon a hydrocarbon where every carbon has only a single bond to no more than two other carbons none of the above
a hydrocarbon where every carbon has only a single bond to no more than two other carbons
What is a functional group? a group that adds function a set of atoms bonded together that give molecules containing them similar properties a set of molecules that are grouped together to form a functional material a group of hydrocarbons that can be used to make new materials none of the above
a set of atoms bonded together that give molecules containing them similar properties
Hydrocarbons with a carbon-carbon double bond are known as ________. alkanes aromatics alkynes alkenes
alkenes
Organic synthesis is useful ________. as an intellectual challenge for the large-scale production of rare organic molecules as a confirmation on the chemical structure of molecules isolated from nature all of the above
all of the above
Why are Ping-Pong balls so highly flammable? They are made from nitrocellulose. They contain residues of camphor. They provide a lot of surface area. all of the above
all of the above
What are the two most common secondary structures in a protein? Check all that apply. alpha helices the sequence of amino acids globular clump pleated sheets peptide bonds polypeptide chain twist
alpha helices pleated sheets
What functional groups are found in all amino acids? aminos and acids ketones and aldehydes alcohols and amides phenols and amines amines and carboxylic acids
amines and carboxylic acids
What is the functional group that links amino acids together to form proteins? a hydrocarbon an amide an amine an ether a carboxylate
an amide
Every biomolecule contains ________. Check all that apply. an oxygen atom a nitrogen atom a phosphorus atom a carbon atom a sulfur atom
an oxygen atom a carbon atom
What are side effects? It is a beneficial aspect of a drug that has not been exploited. any behavior of a drug that is opposite of its primary function It is a multiplying effect seen in a drug due to other interactions. any behavior of a drug that is not fulfilling its primary function none of the above
any behavior of a drug that is not fulfilling its primary function
What is an acid? What is an acid? anything that donates hydronium ions anything that donates hydrogen ions anything that accepts hydrogen atoms anything that donates hydrogen atoms anything that dissolves metal
anything that donates hydrogen ions
A cohesive force is best described as the ________. A cohesive force is best described as the ________. force that allows for molecular cohesion attraction between a liquid molecule and a solute force that holds together the nucleus attraction between molecules of two different substances attraction between two liquid molecules
attraction between two liquid molecules
Why does the melting point of hydrocarbons increase as the number of carbon atoms per molecule increases? The molecular mass also increases. An increase in the number of carbon atoms per molecules also means an increase in the density of the hydrocarbon. because of greater induced dipole-induced dipole molecular attractions Larger hydrocarbon chains tend to be branched.
because of greater induced dipole-induced dipole molecular attractions
Why does the melting point of hydrocarbons increase as the number of carbon atoms per molecule increases? Why does the melting point of hydrocarbons increase as the number of carbon atoms per molecule increases? An increase in the number of carbon atoms per molecules also means an increase in the density of the hydrocarbon. Larger hydrocarbon chains tend to be branched. The molecular mass also increases. because of greater induced dipole-induced dipole molecular attractions
because of greater induced dipole-induced dipole molecular attractions
A battery operates by ________. oxidation both oxidation and reduction reduction none of the above
both oxidation and reduction
The most abundant organic compound on Earth is ________. silicon dioxide water DNA cellulose
cellulose
Which of the following polysaccharides is indigestible by humans but digestible by microorganisms that live in the digestive tracks of termites? sucrose starch glycogen cellulose triglycerides
cellulose
According to the lock-and-key model, in order for a drug to bind it must have the proper ________. Check all that apply. configuration functional groups molecular weight conformation melting point
configuration functional groups conformation
Does soap increase or decrease water's surface tension? increases decreases Soap does not affect water's surface tension. Both; adding a small amount of soap will first decrease water's surface tension but increasing the amount of soap will reverse the effect.
decreases
Which of the following molecules is an alcohol? Check all that apply. CH3COOH CH3CH2OH NaOH
diamond with OH sticking out of right corner , CH3CH2OH
Which of the following molecules is an alcohol? Check all that apply.
diamond with OH sticking out, CH3CH2OH
Which of the following is an aromatic molecule? Check all that apply
diamond with all three lines within, diamond with two lines within and one line in circle without
Which of the following is a saturated molecule? Check all that apply.
diamond with one side open other diamond with one side open, both no lines within
A simple carbohydrate is ________. composed of disaccharides composed of monosaccharides one that cannot be cleaved into smaller components either a monosaccharide or a disaccharide a carbohydrate that can be easily digested
either a monosaccharide or a disaccharide
Both water-soluble and water-insoluble vitamins can be toxic in large quantities. Our bodies are much more tolerant of the water-soluble ones because ________. these are the vitamins that our body doesn't really use our bodies are able to store the excess vitamins in our fat reserves excess quantities of these vitamins are readily excreted they tend to be the weaker vitamins that the body needs a lot of
excess quantities of these vitamins are readily excreted
A fuel cell produces electrical energy from ________.
fuel
Which of the following are not a saccharide? Check all that apply. glycerin glycogen steroids carbohydrates cellulose All of the above are saccharides.
glycerin steroids
It easier to cool off on a dry day vs. a humid day because the rate of evaporation is ________. greater on a dry day and more heat is lost slower on a dry day and less heat is lost greater on a dry day and less heat is lost slower on a dry day and more heat is lost none of the above
greater on a dry day and more heat is lost
Relative to pure water, an aqueous sugar solution ________. has a higher freezing point because crystal formation is promoted by the sugar molecules has a lower freezing point because crystal formation is promoted by the sugar molecules has a higher freezing point because crystal formation is inhibited by the sugar molecules has the same freezing point because most of the solution is water molecules has a lower freezing point because crystal formation is inhibited by the sugar molecules
has a lower freezing point because crystal formation is inhibited by the sugar molecules
What is the leading cause of surface tension in water? What is the leading cause of surface tension in water? ion-dipole interactions evaporation solvation hydrogen bonding
hydrogen bonding
Another name for the "alcohol" of alcoholic beverages is ________. hydroxyethane ethylene ethyl acetate gylcerol
hydroxyethane
Tertiary protein structure is determined by ________. glucose units chemical bonds vitamin abundance intermolecular attractions
intermolecular attractions
Starch is a polysaccharide that ________. Check all that apply. is made by plants to store energy is processed to produce many of the sugars in processed foods is an insoluble fiber aids in the digestion process is made by animals to store energy none of the above
is made by plants to store energy is processed to produce many of the sugars in processed foods
Ethyl alcohol is ________. Check all that apply. low molecular weight organic substance a stimulant a depressant an opioid all of the above
low molecular weight organic substance a depressant
How do anesthetics work to reduce pain? reduce pain causing inflammation prevent neurons from transmitting sensation to the brain reduce synthesis of pain chemicals all of the above none of the above
prevent neurons from transmitting sensation to the brain
The following statement describes what level of structure in a protein? The sequence of amino acids is Asp-Asp-Arg-Asn-Met-Met- etc. secondary structure tertiary structure primary structure quaternary structure none of the above
primary structure
The sequence of amino acids within a protein describes that protein's ________. primary structure secondary structure tertiary structure quaternary structure none of the above
primary structure
The main role of DNA is to provide instructions on how to build ________. carbohydrates lipids proteins all of the above
proteins
The following statement describes what level of structure in a protein? Several separate proteins link together to form an active enzyme. secondary structure quaternary structure tertiary structure primary structure none of the above
quaternary structure
The most complicated protein structure is the ________. secondary structure tertiary structure primary structure quaternary structure
quaternary structure
Two proteins joining together to form a larger protein complex describes a ________. primary structure secondary structure tertiary structure quaternary structure
quaternary structure
The formation of hydrogen bonds between water molecules ________. releases heat energy causes ice to melt and form water increases the amount of molecular vibration makes molecules move farther apart leads to the formation of ice
releases heat energy
The coiling of a chain of amino acids describes a proteins ________. primary structure secondary structure tertiary structure quaternary structure
secondary structure
The following statement describes what level of structure in a protein? The chain of amino acids coils into a helix. secondary structure quaternary structure primary structure tertiary structure none of the above
secondary structure
The following statement describes what level of structure in a protein? The chain of amino acids layers into a large sheet. tertiary structure quaternary structure primary structure secondary structure none of the above
secondary structure
What is the cause of secondary structure in a protein? short range interactions between neighboring amino acids noncovalent interaction of groups of protein molecules long distance conformation changes due to a large number of weak interactions covalent bonding between different protein molecules none of the above
short range interactions between neighboring amino acids
Which of the following is not a complex carbohydrate? Check all that apply. starch sucrose cellulose glycogen glucose All of the above are complex carbohydrates.
sucrose glucose
Surface tension is the ________. Surface tension is the ________. tendency for molecules at the surface of a liquid to hold together tendency for a molecule to pack into spherical shapes tendency for the adhesive forces of a molecule to overcome the cohesive forces rate at which molecules move into and out of the surface of a liquid none of the above
tendency for molecules at the surface of a liquid to hold together
The following statement describes what level of structure in a protein? The set of linked amino acids folds repeatedly and creates a large linear globular shape. quaternary structure secondary structure tertiary structure primary structure none of the above
tertiary structure
What is meant by the term octane rating? the degree of branching in the carbon framework the percentage of octane in the mixture the degree at which the compound ignites a measure of how many degrees it takes to ignite a mixture of octane none of the above
the degree of branching in the carbon framework
What is meant by the term octane rating? What is meant by the term octane rating? a measure of how many degrees it takes to ignite a mixture of octane the degree at which the compound ignites the degree of branching in the carbon framework the percentage of octane in the mixture none of the above
the degree of branching in the carbon framework
What is a reduction? What is a reduction? the reaction of oxygen with a reductant the formation of red compounds in the presence of an oxidant the loss of an electron from the valence shell the gain of electrons the reduction of the number of electrons
the gain of electrons
What is oxidation? What is oxidation? the reduction of oxygen the gaining of electrons the reaction with oxygen the loss of electrons the addition of an electron to the valence shell
the loss of electrons
The cells of your body are about as small as ________. the head of an ant the point of a sewing needle a water molecule the nucleus of an atom
the point of a sewing needle
Nucleic acids determine ________. the rate at which food is metabolized the sequence of amino acids the number of nucleons in a biomolecule the pH of the cell nucleus
the sequence of amino acids
Lipids are insoluble in water because ________. they contain no polar functional groups they are synthesized from carbohydrates they contain a large number of polar hydrocarbon units water cannot compete with the strong attraction lipids have for themselves
they contain no polar functional groups
What is the purpose of the salt bridge in a voltaic cell? to allow for the build up of positively charged ions in one container and negatively charged ions in the other container to allow the Fe2+ and the Cu2+ to flow freely between the two containers to allow for a balance of charge between the two chambers to prevent any further migration of electrons through the wire
to allow for a balance of charge between the two chambers
A strong acid tends ________. Check all that apply. to be strongly polar to form positively charged ions when dissolved in water to form negatively charged ions when dissolved in water to react with other strong acids all of the above
to be strongly polar to form positively charged ions when dissolved in water to form negatively charged ions when dissolved in water
What is the purpose of an enzyme? to bind molecules and keep them out of the body to speed up biochemical reactions to slice sucrose into two ore more pieces to slow down biological reactions none of the above
to speed up biochemical reactions
Which of the following would not be part of the drug discovery process? Check all that apply. changing an old drug a little and testing the new drug for activity training of pharmacists random testing of new compounds for drug activity the construction of a plant for the production of drugs learning the exact shape of various receptor sites examining folklore for herbs and potions
training of pharmacists the construction of a plant for the production of drugs
Chemotherapy is used to treat ________. Check all that apply. viral infections fractures bacterial infections cancer none of the above
viral infections bacterial infections cancer
What is a chemical reaction? when one or more new compounds are formed by rearranging atoms when two liquids mix to form a homogeneous mixture when a liquid undergoes a phase change and produces a solid when two solids mix together to form a heterogeneous mixture when a new element is formed by rearranging nucleons
when one or more new compounds are formed by rearranging atoms
An organic compound is any molecule ________. consisting primarily of orgonium atoms isolated from living organisms, including water grown with organic farming methods with a structure based upon carbon that is a salt obtained from organic creatures
with a structure based upon carbon
Which of the following solutions is the most acidic? a solution with a pH = 10 a solution with a pH = 4 a solution with a pH = 14 a solution with a pH = 7 All of the solutions are basic.
a solution with a pH = 4
Regarding the heating curve, classify these statements as true or false. Drag each statement to the appropriate bin.
true - Heat is added continually from one point to the next.During a phase change, the temperature of a substance remains constant. false - An increase in heat always produces an increase in temperature.The temperature increases continually from one point to the next.
When food spoils, it is a chemical reaction. For example, rancid butter is produced when the fat molecules in the butter undergo oxidation. Another factor that can lead to the decomposition of food molecules is the presence of bacteria, fungi, and other microorganisms. To preserve food, manufacturers try to slow down the rates of such reactions. Note that microorganisms need both water and oxygen for their metabolic reactions to occur. What actions will decrease the rates of the reactions in the food (and therefore slow down spoiling)? Drag each item to the appropriate bin.
-Decreases the rate of reaction Transport food in a refrigerated truck. Lower the water content in the food. Store food in the freezer after preparing it. Store food in airtight containers. -Does not decrease the rate of reaction Keep food hot. Package food in water. Store food at a high oxygen concentration.
Which of the following statements best describe the usual properties of most compounds besides water? Check all that apply. The volume of a material decreases when it solidifies. The volume of a material increases when it solidifies. The molecules become more closely packed when they liquify. The mass of a material increases when it solidifies. The density of a material increases when it solidifies.
-The volume of a material decreases when it solidifies. -The density of a material increases when it solidifies.
Which of the following contains the most heat energy? 1 gram of water at 50°C 1 gram of water at 0°C 1 gram of ice at 0°C 1 gram of water at 100°C 1 gram of steam at 100°C
1 gram of steam at 100°C
According to the following balanced chemical equation, if you want to generate two moles of H2O, how many moles of O2 do you need? 2 H2 + O2 → 2 H2O Express your answer as an integer.
1 moles of O2
Which of the following statements about strong or weak bases are true? Check all that apply. A strong base completely separates into ions in water. A strong base will react with a strong acid. A strong base is always corrosive. A strong base will readily accept protons from even weak acids. A weak base will not react with a strong acid.
A strong base completely separates into ions in water. A strong base will react with a strong acid. A strong base will readily accept protons from even weak acids.
Which of the following statements about strong or weak acids is true? A weak acid readily forms ions when dissolved in water. A weak acid and a strong acid at the same concentration are equally corrosive. A weak acid will react with a strong base. A strong acid will never react with a strong base.
A weak acid will react with a strong base.
Absorbing heat versus releasing heat Any process that absorbs heat requires the addition of heat and energy. Any process that releases heat requires the removal of heat and energy. Classify each process as absorbing or releasing heat. Drag each item to the appropriate bin.
Absorbs heat - sublimation, melting, evaporation releases heat - condensation, freezing
Which of the following has the greatest number of particles? 22.990 g of Na 9.012 g of Be 1 mole of Na 1 mole of Be All are the same.
All are the same.
Which of the following statements about catalysts is NOT true? A catalyst does not change the energy of the reactants or the products. A catalyst can be consumed in a reaction as long as it is regenerated. A catalyst can be used to speed up slow reactions. A catalyst alters the rate of a chemical reaction. All of the above are true.
All of the above are true.
Which of the following describes an electrode? Any material that conducts electrons into a media where electrochemical reactions are taking place. Any material that conducts electrons out of a media where electrochemical reactions are taking place. Any material that is undergoing an oxidation-reduction reaction in a battery. Any material that conducts electrons. Any material that conducts electrons into a media where electrochemical reactions are taking place. OR Any material that conducts electrons out of a media where electrochemical reactions are taking place.
Any material that conducts electrons into a media where electrochemical reactions are taking place. OR Any material that conducts electrons out of a media where electrochemical reactions are taking place.
Which of the following species is undergoing oxidation? 2 CuBr → 2Cu + Br2 Express your answer as an ion.
Br−
Which of the following species is the oxidizing agent? 2 CuBr → 2Cu + Br2 Express your answer as an ion or as a chemical formula.
Cu+
Which of the following species is undergoing reduction? 2 CuBr → 2Cu + Br2 Cu+ Br2 CuBr Cu Br-
Cu+
Which equations are balanced? a) Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) b) 3Al (s) + 3 Br2 (l) → Al2Br3 (s) c) 2HgO (s) → 2 Hg (l) + O2 (g) Equations "b" and "c" are balanced. Equations "a" and "c" are balanced. Only equation "c" is balanced. All of them are balanced.
Equations "a" and "c" are balanced.
A scientist is studying how certain factors affect the rate of a particular reaction. She observes that under one set of conditions, the reaction proceeded much faster than under a different set of conditions. Identify the most likely sets of conditions that produced each reaction rate. Drag each item to the appropriate bin.
Faster reaction - higher temperature larger quantities of reactants Slower reaction- lower temperature smaller quantities of reactants
According to the following reaction, which molecule is acting as a base? H2O + H2SO4 → H3O+ + HSO4- HSO4- H3O+ H2SO4 H2O none of the above
H2O
According to the following reaction, which molecule is acting as an acid? H2O + NH3 → OH- + NH4 + Express your answer as a chemical formula.
H2O
According to the following reaction, which molecule is acting as an acid? H2O + H2SO4 → H3O+ + HSO4 - Express your answer as a chemical formula.
H2SO4
What is pH? It is a numerical scale used to represent acidity or basicity. It is the negative of the log of the hydronium ion concentration. It is the F sound. It is the negative of the log of the acidity of a solution. It is a numerical scale used to represent acidity or basicity. Also it is the negative of the log of the hydronium ion concentration.
It is a numerical scale used to represent acidity or basicity. Also it is the negative of the log of the hydronium ion concentration.
What is a chemical equation? It is any type of reaction that takes place at the equator. It is the sum of the masses of the products and reactants. It is the chemical combination of equal numbers of reactants and products. It is a shorthand notation for illustrating a chemical reaction. It is a picture of the atoms undergoing a chemical equalization.
It is a shorthand notation for illustrating a chemical reaction.
Part A Part complete What is the main characteristic of a strong acid? It is completely dissociated in water. It readily gives up its proton to a base. It is corrosive. It will damage your skin. all of the above
It is completely dissociated in water.
Part A Part complete What is the main characteristic of a strong base? It will damage your skin. It readily accepts an acidic proton. It is corrosive. It is completely dissociated in water. all of the above
It is completely dissociated in water.
What is a reaction rate? It is the ratio of the molecular masses of the elements in a given compound. It is the balanced chemical formula that relates the number of product molecules to reactant molecules. It is the ratio of the masses of products and reactants. It is the speed at which reactants are consumed or product is formed. none of the above
It is the speed at which reactants are consumed or product is formed.
For the following acid-base reaction, identify what is formed in the space marked. HF + KOH ↔ ???? + H2O Express your answer as a chemical formula.
KF
For the following acid-base reaction, identify what compound is formed in the space marked. HNO3 + KOH ↔ ???? + H2O KNO3 KOH2 KOH2NO3 H3ONO3 none of the above
KNO3
Which of the following statements about oxidation and reduction reactions is true? A half-reaction is only used for reduction reactions. More than one electron can be transferred in an oxidation and reduction reaction. Only neutral atoms are formed in oxidation and reduction reactions. In a half-reaction, only half of an electron is transferred. None of the above are true.
More than one electron can be transferred in an oxidation and reduction reaction.
Why does water have a high specific heat? Water is not very dense like metals and therefore doesn't conduct heat as readily. Much of the heat that is added to water is converted to kinetic energy. Much of the added energy is required to break hydrogen bonds. None of the energy is stored as potential energy. none of the above
Much of the added energy is required to break hydrogen bonds.
Balance the following chemical equation. ____ N2 + ____ H2 → ____ NH3 Express your answer as a chemical equation.
N2+3H2→2NH3
According to the following reaction, which molecule is acting as a base? H2O + NH3 → OH- + NH4+ H2O NH3 NH4+ OH- none of the above
NH3
For the following balanced reaction, which of the following is a solid? 2 Na(l) + Cl2(g) → 2 NaCl(s) NaCl 2 Na Cl Cl2 Na
NaCl
Which of the following statements is(are) not true about a neutralization reaction? Check all that apply. A neutralization is, for example, the reaction of hydrochloric acid with sodium hydroxide. One molecule of acid neutralizes one molecule of base. A neutralization is the reaction of a hydroxide ion with a proton. A neutralization is, for example, the reaction of aluminium hydroxide with sodium hydroxide. Water is always formed in a neutralization reaction. None of the above are true.
One molecule of acid neutralizes one molecule of base. A neutralization is the reaction of a hydroxide ion with a proton. Water is always formed in a neutralization reaction.
In a combustion reaction, ethanoic acid (CH3COOH) is burned in the presence of oxygen (O2), producing carbon dioxide (CO2) and water (H2O). Classify each substance as either a reactant or product in the chemical reaction. Drag the appropriate items to their respective bins.
Reactants oxygen ethanoic acid Products carbon dioxide water
Clorox is a laundry bleaching agent used to remove stains from white clothes. Suggest why the name begins with Clor- and ends with -ox. Clor- because it has chlorine, -ox because it is as strong as an ox. Chlor- because it has chlorine ions, -ox because it uses oxygen. Chlor- because it has chlorine ions, -ox because it is reduced. The active ingredient contains chlorine atoms, which behave as strong oxidizing agents.
The active ingredient contains chlorine atoms, which behave as strong oxidizing agents.
How does formula mass differ from atomic mass? The formula mass of a substance is the sum of the atomic masses of the elements is its chemical formula. The atomic mass is the mass of a single atom. The atomic mass of a substance is the sum of the formula masses of the elements is its chemical formula. The atomic mass is the mass of a single atom. The formula mass is the mass of the chemical formula and the atomic mass is the mass of the molecule. They represent the same thing.
The formula mass of a substance is the sum of the atomic masses of the elements is its chemical formula. The atomic mass is the mass of a single atom.
Upon ingestion, grain alcohol, C2H6O, is metabolized into acetaldehyde, C2H4O, which is a toxic substance causing headaches as well as joint pains typical of a "hangover." Is the grain alcohol oxidized or reduced as it transforms into acetaldehyde? The grain alcohol is oxidized. The grain alcohol is reduced. Some of the grain alcohol is oxidized and some is reduced to other products. The grain alcohol is neither oxidized nor reduced.
The grain alcohol is oxidized.
What best describes what happens when an acid such as HCl is mixed with water? HCl is not an acid. A hydroxide ion from the water is transferred to the HCl molecule to form a proton and hydronium ion. A proton from the chlorine nucleus is ejected and captured by a water molecule to form a negatively charged HCl and a new hydronium ion. The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion. none of the above
The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion.
What element is oxidized in the following equation and what element is reduced? Sn2+ + 2 Ag → Sn + 2 Ag+ Check all that apply. The silver, Ag, is oxidized. The silver, Ag, is reduced. The tin ion, Sn2+, is oxidized. The tin ion, Sn2+, is reduced. An oxidation-reduction reaction did not occur.
The silver, Ag, is oxidized. The tin ion, Sn2+, is reduced.
Why do water drops bead on a freshly waxed surface? Water's cohesive forces between molecules results in a spherical shape and prevents the water droplet from spreading out evenly over the wax. The strong cohesive forces between water molecules attract each other and the result is a sphere, which is squashed down into a bead by the force of gravity. A freshly waxed surface carries a small electrical charge, which repel the outer electrons on the water molecules. The wax, which is nonpolar, pushes the water into a bead shape.
The strong cohesive forces between water molecules attract each other and the result is a sphere, which is squashed down into a bead by the force of gravity.
Why does water expand when it goes from a liquid to a solid? Ice molecules are bigger than water molecules. The liquid water molecules are bigger and shrink when cooled. The liquid has a higher density than the ice. The water molecules become aligned in a way that creates extra volume. none of the above
The water molecules become aligned in a way that creates extra volume.
Why does sweat cool you off? The water molecules leaving the skin as vapor absorb the heat from your skin. The sweat glands require energy to produce water. Sweat has a large amount of kinetic energy and that makes it easy to evaporate. The water molecules absorb the heat in your skin. none of the above
The water molecules leaving the skin as vapor absorb the heat from your skin.
The yeast in bread dough feeds on sugar to produce carbon dioxide. Why does the dough rise faster in a warmer area? The yeast tends to "wake up" with warmer temperatures, which is why baker's yeast is best stored in the refrigerator. There is a greater number of effective collisions among reacting molecules. The rate of evaporation increases with increasing temperature. Atmospheric pressure decreases with increasing temperature.
There is a greater number of effective collisions among reacting molecules.
Why does blowing over hot soup cool the soup? Check all that apply. When you blow over the top of a bowl of hot soup, you increase net evaporation. When you blow over the top of a bowl of hot soup, you remove the warm vapor which tends to condense and reduce net evaporation above the bowl When you blow over the top of a bowl of hot soup, you decrease net evaporation. When you blow over the top of a bowl of hot soup, the moving air reduces pressure atop the soup and increases the rate of evaporation. None of the above.
When you blow over the top of a bowl of hot soup, you increase net evaporation. When you blow over the top of a bowl of hot soup, you remove the warm vapor which tends to condense and reduce net evaporation above the bowl When you blow over the top of a bowl of hot soup, the moving air reduces pressure atop the soup and increases the rate of evaporation.
Which of the following statements describes a basic solution? [H3O+] > [OH-] [H3O+] × [OH-] ≠ 1 × 10-14 [H3O+]/[OH-] = 1 × 10-14 [H3O+] < [OH-] [H3O+]/[OH-] = 1
[H3O+] < [OH-]
Which of the following statements describes an acidic solution? [H3O+] < [OH-] [H3O+]/[OH-] = 1 [H3O+] > [OH-] [H3O+]/[OH-] = 1 × 10-14 [H3O+] × [OH-] ≠ 1 × 10-14
[H3O+] > [OH-]
The ________ is what needs to be overcome in a reaction so that it can proceed to the products.
activation energy
What is an endothermic reaction? It is a reaction where the products have more energy than the reactants. It is a reaction where there is a net adsorption of energy from a reaction. It is a reaction that requires heat as a reactant. all of the above none of the above
all of the above
Which of the following statements best describes an anode? the place from which electrons are flowing away from the negatively charged electrode of a battery or electrochemical apparatus the place where oxidation is taking place in a battery or electrochemical apparatus all of the above none of the above
all of the above
Condensation is ________. Check all that apply. always a cooling process always a warming process an endothermic process sometimes a warming process sometimes a cooling process an exothermic process
always a warming process an exothermic process
The specific heat of a substance is the ________. amount of potential energy in a material that is released when a substance undergoes combustion and gives off heat temperature at which a given mass's heat increases amount of heat energy that is stored in chemical bonds temperature at which a compound starts to melt amount of heat required to change the temperature of a given mass
amount of heat required to change the temperature of a given mass
Evaporation is ________. Check all that apply. an endothermic process always a warming process sometimes a warming process sometimes a cooling process an exothermic process always a cooling process
an endothermic process always a cooling process
What is a base? anything with a bitter taste anything that can be used to clean drains anything that accepts a hydrogen ion anything that accepts a hydroxide ion anything that donates a hydroxide ion
anything that accepts a hydrogen ion
What is an acid? anything that dissolves metal anything that donates hydronium ions anything that accepts hydrogen atoms anything that donates hydrogen ions anything that donates hydrogen atoms
anything that donates hydrogen ions
In a chemical equation the coefficients ________. appear before the chemical formulas of the reactants should always sum up to those of the products appear as subscripts Two of the above are correct.
appear before the chemical formulas
An adhesive force is best described as ________. attraction between two different molecules attraction between a liquid molecule and a solute the force that allows for molecular adhesion the force that holds together the nucleus attraction between two liquid molecules
attraction between two different molecules
Given the following energy profiles, which of the following reactions is endothermic? R= reactants P= products a b c d none of the above
d r with line starting down then goes up and starts going down a bit
A cohesive force is best described as the ________. force that holds together the nucleus attraction between two liquid molecules attraction between a liquid molecule and a solute force that allows for molecular cohesion attraction between molecules of two different substances
attraction between two liquid molecules
If the following graphs are for the same reaction, which one is most likely the one with an added catalyst? a b c d All have had catalyst added.
b r starting in middle goes up a bit then way down
The heating curve For Parts B and C, consider this heating curve for H2O at atmospheric pressure. (Figure 1) Reading the graph from left to right, the first point represents H2O before any heat is added. The last point represents H2O at the end of the heating process. The numbers on the vertical axis indicate the temperature (in degrees Celsius) for each point. Part B Part complete Reading the graph from left to right, what phase changes occur? Check all that apply. melting boiling freezing condensation
boiling
X + Y → Z Which of the above reactions would proceed the fastest? a b c all proceed at same rate not enough information given
c low long rectangle
When you increase the temperature of a substance, the molecules vibrate ________. faster and the molecules move farther apart faster and the molecules more closer together slower and the molecules move closer together slower and the molecules move farther apart none of the above
faster and the molecules move farther apart
Heat is absorbed by a substance when that substance ________. condenses freezes melts evaporates cools
melts evaporates
What is an exothermic reaction? It is a reaction that requires heat as a reactant. It is a reaction where the products have more energy than the reactants. It is a reaction where there is a net adsorption of energy from a reaction. all of the above none of the above
none of the above
What is the source of acid rain? All rain is acid rain because rain has a hydronium ion concentration greater than 10-7 M. All rain is acid rain because rain has a pH is less than 7. Rain is normally basic, but depending on the weather it can get slightly acidic. Acid rain is from dissolved carbon dioxide. none of the above
none of the above
Which of the following statements best describes a cathode? the place from which electrons are flowing away from the negatively charged electrode of a battery or electrochemical apparatus the place where oxidation is taking place in a battery or electrochemical apparatus all of the above none of the above
none of the above
The hydroxide ion, HO-, is a ________. proton donator very strong acid polyatomic ion unique form of water
polyatomic ion
The hydronium ion, H3O+, is a ________. Check all that apply. very strong base proton acceptor polyatomic ion proton donor unique form of water
polyatomic ion proton donor
Surface tension is the ________. tendency for the adhesive forces of a molecule to overcome the cohesive forces tendency for molecules at the surface of a liquid to hold together tendency for a molecule to pack into spherical shapes rate at which molecules move into and out of the surface of a liquid none of the above
tendency for molecules at the surface of a liquid to hold together
What is a reduction? the gain of electrons the loss of an electron from the valence shell the reaction of oxygen with a reductant the formation of red compounds in the presence of an oxidant the reduction of the number of electrons
the gain of electrons
What is oxidation? the addition of an electron to the valence shell the loss of electrons the reduction of oxygen the reaction with oxygen the gaining of electrons
the loss of electrons
What is the activation energy? the minimum amount of energy to break the bonds in reactants the energy difference between the reactants and the products the amount of energy required to separate reactants from the products the amount of energy required to activate a phase change the hill
the minimum amount of energy to break the bonds in reactants
It is important to protect water pipes in your home from freezing because ________. blocked water behind the frozen ice will build up pressure and will burst the pipes the ice will promote serious erosion of the pipe material freezing water will scrape the lining from the insides of the pipes water expands more than the pipe material, which will fracture the pipes if water in them freezes all of the above
water expands more than the pipe material, which will fracture the pipes if water in them freezes
What are the formula masses of water, H2O; propene, C3H6; and 2-propanol, C3H8O? water: 18 amu; propene: 42 amu; 2-propanol: 60 amu water: 18 amu; propene: 40 amu; 2-propanol: 58 amu water: 18 amu; propene: 44 amu; 2-propanol: 64 amu water: 18 amu; propene: 42 amu; 2-propanol: 62 amu
water: 18 amu; propene: 42 amu; 2-propanol: 60 amu
