General Chapter 6 Assessment answers

Section 1 1. What is chemistry? The study of matter 2. What is the definition of matter? Anything that has mass and takes up space 3. What makes up matter? atoms

4. What are the three parts of an atom? Neutrons, protons, electrons 5.Which particle of the atom is positive? protons 6.Which particle of the atom is negative? electron

7. Where is the neutron and proton located in the atom? nucleus 8.Where is the electron located in the atom? Energy levels 9. How many electrons does the first energy level hold? 2

10.How many electrons does the second energy level hold? Define element. substance consisting entirely of one type of atom

12. How are elements identified on the periodic table? By the symbol 13. What information does the atomic number of each element tell you? Number of protons

14. If you know the number of protons of an element, then you know the number of electrons. 15. How does the atom of an isotope differ from the atom of the same element? The neutrons for an isotope are more than the regular atom

16. What is a compound? formed when 2 or more different elements combine 17. What are the two types of chemical bonds? Covalent bonds Ionic bonds

18.What is a molecule? – compound in which the atoms are held together by covalent bonds. 19. When a compound is formed through ionic bonds, what is transferred? electrons

20. What is an ion? – atom that has a positive or negative charge because they have lost or gained 1 or more e Compare and contrast an ionic bond, covalent bond and van der Waals forces? Covalent and ionic bonds are between atoms Van der Waals forces are between molecules

6.2 assessment answers 1.What is the definition for a chemical reaction? Process that changes one set of chemicals into another set of chemicals by breaking and forming chemical bonds 2. What is the difference between a physical change and a chemical change? Physical – change in appearance not composition Chemical – change in composition

3.Compare and contrast products and reactants in a chemical equation. Both are in a chemical equation reactants are on the left side of the arrow Products are on the right side of the arrow 4.What does the arrow mean when writing a chemical equation? Yields which means what do you have at the end of the reaction

5. What does the law of conservation of mass state? Matter cannot be created or destroyed 6.How do you balance a chemical equation? Number of atoms on each side of the arrow must equal each other You may have to add coefficients and subscripts to make the equation balance

7. What is the difference between a coefficient and a subscript in a chemical equation? A coefficient is the number in front on the reactant or product Subscript is the number at the bottom behind an atom 8. How do you find out the total number of atoms in a chemical formula? If there is a subscript and a coefficient, you must multiply the atoms and then add them up

9. Define activation energy. The minimum amount of energy needed for reactants to form products in a chemical reaction. 10. Contrast an exothermic reaction from an endothermic reaction. Exothermic means energy is released after the reaction Endothermic means energy is absorbed after the reaction

11. What is purpose of a catalyst? Lowers the activation energy of the chemical reaction 12.What type of catalyst is an enzyme? Biological catalyst

13.What binds to the enzyme? Reactants called substrates 14. What is an active site? Specific place on an enzyme where the substrate binds 15. What are the factors that affect enzyme activity? pH, temperature and other substances

6.3 assessment answers 1.What is the definition for polarity? The characteristic of some molecules that have 2 opposite poles with an unequal distribution of charges 2.What molecule is a polar? Water, H 2 0

3. What is a hydrogen bond? a weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom. 4. What is definition of a mixture? Combination of two or more substances in which each substance retains its individual characteristics because they do not combine chemically

5.What are the two types? Homogenous and heterogenous 6. What is the difference between a homogeneous mixture and a heterogeneous mixture? Homogenous - even composition of the substance throughout the mixture Heterogenous – components remain distinct; they can be see individually

7. Compare and contrast a solvent and a solute. Both are part of a solution Solvent is a substance in which a solute is dissolved Solute is a substance which is dissolved in a solvent to make a solution 8. Why is water the universal solvent? Because it mixes well with other substances because of its polarity

9. Water is cohesive and adhesive. What is the difference between the two? Cohesive – molecules stick to each other Adhesive – molecules stick to other types of things 10. What type of mixture is a suspension? a heterogeneous mixture in which the particles settle out over time

11. What were the examples of a colloid? Paint, blood, mayonnaise, milk 12. Define acids and give pH number substances that release hydrogen ions (H + ) when dissolved in water; pH values lower than 7.

13. Define bases and give pH number. substances that release hydroxide ions (OH – ) when dissolved in water Bases have pH values higher than 7 14.What is the definition for pH? the measure of concentration of H + (hydrogen Ion)in a solution 15. What is the purpose of a buffer? To keep pH in a certain range

6.4 assessment answers 1.Which element is a component of almost all biological molecules? carbon 2. How many covalent bonds can a carbon atom form with other atoms? four

3. What is the name of compounds that carbon forms? organic 4. What is a macromolecule? Large molecules that are formed by joining smaller organic molecules together 5. What is the difference between monomers and polymers? Monomers are small molecules that make up polymers

6. What are the four major categories of macromolecules? Proteins, carbohydrates, lipids, nucleic acids 7.What are the elements that compose carbohydrates? Carbon, hydrogen and oxygen 8. What is the difference between a monosaccharide and a disaccharide? Mono- is one sugar molecule Dissaccharide – is two sugar molecules joined

9.What were some examples of lipids? Fats, oils, waxes 10. Which macromolecule is made of the monomer amino acids? protein 11.What were the three types of nucleic acids? DNA, RNA, ATP 12.What is the monomer of proteins? Amino acids

13.What are the components of nucleic acids? Phosphate, Nitrogen base, ribose sugar 14.Which of the macromolecules cannot dissolve in water? Lipids 15. Which of the macromolecules have the function of speeding reactions? Proteins in the form of enzymes