Chpt 2 Quiz

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Missouri State University, West Plains *

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100

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Chemistry

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Jan 9, 2024

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 The term for a solution with a low pH number, such as lemon juice or vinegar, is acidic .target 1 of 6  2. The term for a solution that has an equal concentration of H + and OH - is neutral .target 2 of 6  3. The term for a solution with a high pH number, such as ammonia or bleach, is basic .target 3 of 6  4. An acid is a compound that donates H + to a solution.target 4 of 6  5. The higher the pH number, the higher the concentration of OH - in a solution.target 5 of 6  6. A substance that accepts H + when they are in excess and donates H + when their concentration drops is called a(n) buffer . Part A __________ bonds hold the oxygen and hydrogen atoms in a molecule of water together. Ionic Hydrogen Polar covalent Nonpolar covalent Correct Polar covalent bonds connect hydrogen and oxygen atoms in a molecule of water to make water molecules polar. a= Glycerol b= Double bond c= Single bond d= Unsaturated fatty acid e= Saturated fatty acid f= Triglyceride Drag the labels to the appropriate locations on this molecule. Not all labels will be used.  amino acid  unsaturated fatty acid Target D refers to the long bent chain. Target 1 of 6  glycerol Target 'A' refers to a portion of the molecule that is C H 2 C H C H 2 with a single oxygen atom single-bonded to each carbon. Three long chains are connected to this portion. Target 2 of 6  double bond Target B refers to a connection between the balls of a chain where the chain bends. Target 3 of 6  triglyceride Target F refers to the entire molecule. Target 4 of 6  single bond Target C refers to a connection between the balls of two straight chains. Target 5 of 6  saturated fatty acid Target E refers to one long straight chain. Target 6 of 6

This graph illustrates the course of a chemical reaction with and without an enzyme. While the products and reactants are the same, the presence of an enzyme changes the amount of energy required for the reaction to begin. Which curve shows the course of the reaction in the presence of an enzyme-- the black curve or the red curve? Which line represents the activation energy for that reaction--a, b, or c? black curve; line a black curve; line b black curve; line c red curve; line a red curve; line b

red curve; line c Use the graph and your knowledge of enzymes to identify the three true statements about enzymes. Chemical reactions cannot occur without enzymes. Enzymes lower the overall energy input needed for a reaction to occur. By binding to reactant molecules, enzymes make it easier for the bonds in the molecules to break apart. Only reactions that are controlled by enzymes require activation energy. Reactants cannot convert to products without an initial input of energy to start the reaction. Correct For a chemical reaction to begin, chemical bonds in the reactant molecules must be broken. This process requires that the molecules absorb energy from their surroundings. The energy that must be invested to start a reaction is called activation energy because it activates the reactants and triggers the chemical reaction. Enzymes enable metabolism to occur by reducing the amount of activation energy required to break the bonds of reactant molecules. Part A Water readily sticks to many other substances, a property called ______. cohesion adhesion hydrophobic bonding polarity Part B Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____. cohesion and resulting surface tension high specific heat adhesion Part C Which best describes how charges are distributed on a water molecule? The oxygen end is positive relative to the end with the two hydrogen atoms. The oxygen end is negative relative to the end with the two hydrogen atoms. Part D Relative to other substances, water tends to resist changes in temperature. Why? Water is extremely dense, and like all dense materials, it can absorb a great deal of heat with a relatively small change in temperature.

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Water is abundant. Large bodies of water resist changes in their temperature simply because they are massive objects. Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules. Water is highly adhesive. Pure water does not resist temperature change, but if water is bonded to other substances, molecules will tend to "stay put" and resist increases in their motion. Part E Water is sometimes called the "universal solvent." Is that accurate? Certainly. Water's polar nature means that it can adhere to and dissolve all other substances. Not at all. Only salts and carbohydrates can be dissolved in water. For the most part. Water readily dissolves hydrophobic substances but not hydrophilic ones. For the most part. Water readily dissolves most substances, but not hydrophobic ones. *Hypothesis Trans fats have a negative effect on cardiovascular health. Prediction Eating more trans fats will lead to greater cardiovascular health problems. Experiment Feed some people a diet high in trans fats and feed others a diet low in trans fats. Data Collection Take blood samples to measure fat and cholesterol levels in the two groups. Practical Limitations Is it possible to completely regulate people´s diets? Are other lifestyle factors affecting cardiovascular health? Ethical Limitations Are we putting individuals´health at risk? Explanation: In the scientific method, observation drives scientists to ask questions, that can later lead to a hypothesis, meaning a testable answer related to that question. Scientists test their hypotheses by formulating predictions and make experiments to check if they were correct, considering the possible limitations of data and methods. 1.Factor(s) that varied from the start of the study smoking status (smoking vs. non-smoking) percentage of different types of fats eaten total food intake activity level 2.Factor(s) kept consistent from the start of the study sex of participant 3.Outcome(s) measured in the study deaths from coronary heart disease number of non-fatal heart attacks A relative risk (RR) of 1 means the risk of heart disease is the same compared to an equivalent intake of carbohydrates. 2. An RR greater than 1 means the risk of heart disease is higher compared to an equivalent intake of carbohydrates. 3. An RR less than 1 means the risk of heart disease is lower compared to an equivalent intake of carbohydrates. 4. The RR for monounsaturated fat is 0.81, suggesting that increasing intake of this type of fat by 5% decreases the risk of heart disease.

5. The RR for polyunsaturated fat is the lowest among the fats tested, suggesting that these fats are most beneficial for cardiovascular health. 6. The RR for saturated fat is 1.17. For each 5% increase in energy consumed in this form of fat, there is a 17% increase in heart disease risk. 7. The RR of trans fat is the highest among the types of fats tested, suggesting that these fats pose the greatest health risk. 8. For each increase of 2% in energy from trans fats, there is a 93 % increased risk of heart disease. 1. A(n) ___ bond forms when one atom gives up one or more electrons to another atom. 2. ionic 3. Atoms or molecules with a net electric charge due to the loss or gain of one or more electrons are ___ 4. ions 5. A(n) ____ bond involves the sharing of electron pairs between atoms, also known as a molecular bond. 6. covalent 7. When one pair of electrons is shared between two atoms, a ____ bond is formed. 8. single 9. When two pairs of electrons are shared between two atoms, a ____ bond is formed. 10. double 11. A ____ bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms. As a result, one end of the molecule has a slightly negative charge and the other a slightly positive charge. 12. polar 13. Atoms involved in a _____ bond equally share electrons; there is no charge separation to the molecule. 14. nonpolar 15. A weak bond called a ____ bond results from an attraction between a slightly positive region in a molecule and a slightly negative region in the same or a different molecule. 16. hydrogen Food processors are phasing out the use of which types of fats, because research has shown them to be particularly unhealthy? Fats containing omega-3 fatty acids Vegetable and fish oils Unsaturated fats Saturated fats and trans fats Saturated fat comes mainly from animal sources. It can raise blood cholesterol and contribute to type 2 diabetes. Most trans fats are made through a process called partial hydrogenation. Trans fats can increase blood cholesterol and contribute to cardiovascular disease. As of 2018, trans fats are no longer allowed in food production. To a large extent, a protein's function is dependent upon its shape. What determines a protein's shape? The sequence of amino acids The number of peptide bonds The number of amino acids The location of the active site Which four elements make up the bulk of living cells? Oxygen, carbon, hydrogen, and nitrogen Water, calcium, carbon, and nitrogen Calcium, oxygen, hydrogen, and carbon

Carbon, oxygen, sodium, and nitrogen What will be accomplished by lowering the activation energy of a reaction? The reaction will proceed more quickly. The reaction will proceed more slowly. The reaction will stop completely. The reaction will reverse. What are the monomers of proteins? Amino acids Glucose Fatty acids Nucleic acids The following graph shows the average pH of the ocean over the last 20 million years of Earth's history. What can be concluded from the graph? Select all that apply. Average ocean pH has fluctuated over the millennia from just over 8.0 to about 8.3. In the last 20 million years of Earth's history, the average pH has never gone below 8.0.

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The correct answers are as:  In 2016, atmospheric CO 2 was at 400 ppm, and oceanic pH was at 8.1 .target 1 of 8target 2 of 8  2. Under the Optimistic scenario, CO 2 concentrations in the atmosphere will increase but will remain under 600 ppm through 2090.target 3 of 8  3. Under the Middle Ground scenario, CO 2 concentrations in the atmosphere will get close to, but are not projected to exceed 700 ppm by 2090.target 4 of 8  4. Under the Pessimistic scenario, CO 2 concentrations in the atmosphere are projected to exceed 800 ppm by 2090.target 5 of 8  5. Across all three scenarios, ocean pH falls below 8.0 by 2090.target 6 of 8  6. From the information in the graphs, you can conclude that oceanic pH and atmospheric CO 2 concentration are negatively (or inversely) correlated.target 7 of 8

 7. Although not reflected in this graph, you can infer that as atmospheric carbon dioxide increases, oceanic carbon dioxide concentrations also increase, suggesting that the two variables are positively (or directly) correlated. 1. 400ppm , 8.1 . . 2. 600ppm 3. 700ppm 4. 800ppm 5. 8.0 6. negatively 7. positively FALSE: As atmospheric CO2 concentrations reach 840 ppm, or three times the preindustrial level, the calcification rate will be reduced to 30 mmol/m2/day. FALSE: Declining coral calcification rates suggests a decrease in the level of bicarbonates and an increase in the level of carbonates in seawater. TRUE: As atmospheric CO2 concentrations reach 560 ppm, or double the preindustrial level, the coral calcification rate is projected to be reduced by more than two-thirds from what it was at the preindustrial level. FALSE: The data in this graph could also be plotted as a pie chart. TRUE: Coral reef calcification rates are projected to steadily decline as atmospheric CO2 concentrations increase. TRUE: Although not reflected in the graph, based on how ocean acidification works the relationship between oceanic pH and coral calcification rates can be predicted to be positively (or directly) correlated. How might rising atmospheric CO 2 concentrations lower the pH of the oceans? In the oceans, dissolved CO 2 can act as a buffer. CO 2 can combine with the salt dissolved in seawater to form acids. As atmospheric CO 2 levels rise, average global temperatures will rise, and more water molecules will release H + ions. As CO 2 concentrations rise, excess CO 2 is absorbed by the oceans. CO 2 in the oceans can react chemically with water to form acid. Starch and glycogen are complex carbohydrates made by joining together long chains of __________ molecules. sucrose cellulose glucose

fructose

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Chpt 2 Quiz

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