CP Chemistry Semester 1 Final Test Review

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1 Mass in grams CP Chemistry Semester 1 Final Test Review 1. Know the symbol and the power of 10 for the following metric prefixes: A. Mega M 10 6 D. deka da 10 1 G. milli m 10 6 B. kilo k 10 3 E. deci d 10-1 H. micro µ 10-6 C. hecto h 10 2 F. centi cm Metric Conversions: Give the value of the following in the units indicated. a cm = m e. 934 µm = mm b. 8 dag = 800 dg f. 550 ml = 0.55 L c. 35 km = 3,500,000 cm g. 6,450,000 mg = _6.450_kg d. 520 ml = 0.52 L h g = 75 mg Problems: Calculate the following using correct units and significant digits. 3. A metal has a volume of 8.4 ml and a mass of 32.0 g. What is its density? 3.8 g/ml 4. A solid object has a density of 7.00 g/ml and a volume of 12.0 ml. What is its mass? 84.0 g 5. An object has a density of 9.0 g/ml and a mass of 41.2 g. What is its volume? 4.6 ml 6. Be able to read and interpret data off a line graph. MASS v. VOLUME FOR SAMPLES OF SUBSTANCE X a. If the mass is 30 grams, what is the volume? 15 ml b. What is the mass if you have 10 ml of substance X? 20 g c. Calculate the approximate slope of the line. y/ x Slope = (30-20)/(15-10) = 2 d. Calculate the approximate density of the substance X. density = slope of mass v. volume graph! = 2 g/ml (calculated in question c.) Volume in ml 7. Explain the difference between a homogeneous mixture (solution) and a heterogeneous mixture. Give an example of each. Heterogeneous Mixture : A mixture that does not blend smoothly throughout Sand and water Homogeneous Mixture: A mixture that has constant composition throughout salt and water 8. Explain the difference between a physical change and a chemical change. Give an example of each. Physical Change : A change in which no new substances are formed melting, boiling, distillation, crystallization, dissolving, Chemical Change: New substances are formed combustion, burning, decomposition 9. Conservation of mass problems (mass of reactants = mass of products): a. Water is decomposed into hydrogen and water. If 10.0 grams of hydrogen and 79.5 grams of oxygen are collected, how much water did you start with? 10.0 g hydrogen g oxygen = 89.5 g product = 89.5 g reactant (water)

2 b. If 25 grams of sodium reacts with chlorine to form 99 grams of salt (NaCl). How many grams of chlorine reacted? Reactants: 25 g sodium + X g chlorine Products: 99 g salt (sodium chloride) 25 g + X g = 99 g X = 99 g -25 g = 74 g chlorine 10. What are the differences in the atomic number, atomic mass and mass number? Atomic number Definition The number of protons in an element. It determines what element it is. In a neutral atom, atomic number also equals the number of electrons. ON THE PERIOIC TABLE. How to calculate # p + (or # e - in a neutral atom) Mass number The mass of a specific isotope p + + n 0 Atomic mass The weighted average mass of all naturally occurring isotopes. ON THE PERIODIC TABLE. Weighted average of mass number and percent abundance of all isotopes. 11. What is the definition of an isotope? Why do isotopes of the same element (ex. carbon-12, carbon-13, carbon-14) have different mass numbers? An isotope is an element with different number of neutrons. Isotopes of the same element have different mass numbers because they have different numbers of neutrons (mass number = #p + + #n 0 ) 12. Which isotope is the standard for the atomic mass unit (amu)? 12 amu = mass of 1 carbon-12 atom (1 amu = 1/12 carbon-12 mass number) 13. Know how to calculate the number of protons, neutrons and electrons in an isotope when given its mass number and atomic number. Element atomi c numb er mass numb er proto ns neutro ns electro ns Isotope name (using name) Copper (Cu) Copper-64 Neon (Ne) Neon-21 Zinc (Zn) Zinc-65 Isotope name (using symbol) Magnesium (Mg) Magnesium- 26

3 14. In a chemical reaction, what changes in the atom and what is formed? Electrons are shared, gained or lost and a new compound is formed In a nuclear reaction, what changes in the atom and what is formed? The nucleus of an atom changes and a new element is formed 15. Know that the forms of natural radioactivity are alpha, beta, and gamma. symbol Mass (amu) charge Alpha α 4 2+ Beta β 0 1- Gamma γ Which form of radiation has the lowest energy (ex. can be stopped by paper)? alpha Which form has the highest energy (ex. will pass through your body and several feet of concrete)? gamma 17. Know how to balance a nuclear reaction selecting the correct particle. What particles would you use to balance the following nuclear reactions? A. (a) (b) (c) B. (a) (b) (c) C. (a) (b) (c) 18. Use the following data table on the isotopes of element X to answer Questions A-C listed below: Isotope Mass in amu Percent CALCULATE: Abundance % (Mass number) X (% abundance)/100 X X X Weighted average atomic mass (SUM OF CALCULATED VALUES): Weighted avg. atomic mass = (Mass x ) X-20 + (Mass x ) X-21 + (Mass x ) X-22 A. What is the weighted average atomic mass of element X? amu B. Using the periodic table what is the identity and atomic number of element X? Neon, Assume the following three isotopes of element Z exist: Z-248, Z-252, and Z-259. If the atomic mass of Z is amu, which of these isotopes is most abundant? Since the atomic mass is the weighted average, the most abundant will be the isotope with the mass number closest to the atomic mass: Z- 259.

4 20. Give the (1) electron configuration (2) noble gas shorthand and (3) orbital filling diagram for the following elements. a. Sulfur (atomic number 16) 1s 2 2s 2 2p 6 3s 2 3p 4 [Ne]3s 2 3p 4 1s 2s 2p 3s 3p b. Copper (atomic number 29) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9 [Ar]4s 2 3d 9 1s 2s 2p 3s 3p 4s 3d 21. Give the Lewis electron dot diagrams for the following elements. A. Mg Mg D. F F B. K K E. O O C. Ge Ge F. B B 22. Periodic Table Organization A. The periodic table is arranged by increasing atomic number. B. Rows on a periodic table are called periods. Columns on a periodic table are called groups or families. C. Properties of elements in the same period change (increase or decrease) as you move left to right or right to left and repeat as you move from one to the next. D. Properties of elements in a group or family are similar. E. All atoms of the same element contain the same number of what particle? Protons F. Identify the location of these groups or families: Alkali Metals (Group 1A) Alkaline Earth Metals (Group 2A) Halogens (Group 7A) Noble Gases (Group 8A) G. Given the electron configuration of the atom, identify the location of the element on the periodic table: i. [He]2s 2 2p 4 ii. [Kr]5s 2 iii. [Ne]3s 2 3p 6 iv. [Ar] 4s 1 v. [Ne]3s 2 3p 5 i. Oxygen, Atomic Number 8, Period 2, Group 6A, Nonmetal ii. Strontium, Atomic Number 38, Period 5, Group 2A (Alkaline Earth Metals), Metal iii. Argon, Atomic Number 18, Period 3, Group 8A (Noble Gases), Nonmetal iv. Potassium, Atomic Number 19, Period 4, Group 1A (Alkali Metals), Metal v. Chlorine, Atomic Number 17, Period 3, Group 7A (Halogens), Nonmetal 23. Periodic Table Trends Know the definitions of each property and the general trends by column and row for: Electronegativity: Attraction of an atom for electrons Ionization Energy: Energy required to remove an electron from an atom Atomic Size (atomic radius): Distance between the center of an atom to the outer edge of the electron cloud (measured as half the distance between two nuclei) Ionic size (ion radius): Distance between the center of an ION (WHICH HAS LOST OR GAINED ELECTRONS) to the outer edge of the electron cloud A. Identify which of the element in each pair has the LARGER atomic radius: a. K and Sc b. Cl and I c. Ca or Ga d. Se or O

Atomic Size and Ionic Size Electronegativity and Ionization Energy B. List the elements in order of INCREASING electronegativity: a. O, S, Se: Se, S, O b. Al, Cl, P: Al, P, Cl c.

5 Atomic Size and Ionic Size Electronegativity and Ionization Energy B. List the elements in order of INCREASING electronegativity: a. O, S, Se: Se, S, O b. Al, Cl, P: Al, P, Cl c. Ca, Mg, Sr: Sr, Ca, Mg C. Which of these elements has the LOWEST and which has the HIGHEST ionization energy? Fr, Rn, He or H: Fr has the lowest ionization energy; He has the highest. Electronegativity and Ionization Energy Atomic Size and Ionic Size 24. How many electrons does a neutral atom have? The same number as the number of protons (atomic number) 25. An ion is an atom that has gained or lost electrons in order to become more stable; by achieving the noble gas configuration. 26. Complete the table for the ATOMS and IONS of these elements: Element Element Atomic # Valence Total Total Ion symbol Symbol Number Electrons in the Atom Number of Electrons in an Atom Number of Electrons in an Ion Magnesium Mg Mg 2+ Oxygen O O 2- Phosphorus P P 3- Aluminum Al Al 3+ Iodine I I - Lithium Li Li A metallic bond occurs between what types of elements? Two or more metals A metallic bond is the attraction between positively charged metal cations and negatively charged free-floating electrons ( sea of electrons ).

6 28. An ionic bond forms between what types of elements? A metal and a nonmetal An ionic bond is the attraction between positively charged metal cations and negatively charged anions. Electrons are transferred from the metal (cation) to the nonmetal (anion). 29. A molecule has a covalent bond and forms between what types of elements? Two or more nonmetals The bond in a molecule occurs when electrons are shared. 30. A chemical formula tells you how many of each atom are in the compound, as indicated by subscripts. MgCl 2 means 1 magnesium and 2 chlorine atoms in the compound. CCl 4 means 1 carbon and 4 chlorine atoms in the compound. 31. Complete the tables below: Compound Name Ionic Compound or Molecule? Chemical Formula Iron (III) Sulfate Ionic Fe 2 (SO 4 ) 3 Disulfurpentoxide Molecule S 2 O 5 Aluminum Sulfide Ionic Al 2 S 3 Trinitrogenmonofluoride Molecule N 3 F Chemical Formula Ionic Compound or Molecule? Compound Name NiCl 3 Ionic Nickel (III) chloride P 3 O 4 Molecule Triphosphorus tetroxide CBr 4 Molecule Carbon tetrabromide BeF 2 Ionic Beryllium fluoride 32. Recognize the correct Lewis Dot structures for molecules: The electron dot formula for hydrogen sulfide, H 2 S has 8 valence electrons. C is the correct structure The electron dot structure for CN- has 10 valence electrons. III is the correct answer

7 33. Using the electronegativities below determine the type of bond that would form between these: Cl: 3.16 O: 3.5 Na: 0.93 P: 2.19 Cl-P Na-Cl Na-O Cl-Cl Polar Ionic Ionic Nonpolar Covalent Covalent 33. Balance the following chemical equations: A. 1 C 3 H O 2 3 CO H 2 O B. 2 Al + 6 HCl 2 AlCl H 2 C. Silver nitrate and copper metal react to form copper (II) nitrate and silver metal 2 AgNO Cu 1 Cu(NO 3 ) Ag D. Tetraphosphide and dioxide react to form diphosphorus trioxide 1 P O 2 2 P 2 O Why don t we change subscripts when we balance chemical equations? If you change the subscript it changes the compound. (example: O 2 is oxygen gas but O 3 is ozone). We only use coefficients in front of the formula to balance equations. 35. Balance the following equations and indicate the type of reaction taking place: a) 3 Ca(OH) Al 2 (SO 4 ) 3 3 CaSO Al(OH) 3 b) 3 Mg + 1 Fe 2 O 3 2 Fe + 3 MgO c) 1 C 2 H O 2 2 CO H 2 O d) 2 PbSO 4 2 PbSO O 2 e) 2 SO2 + 1 O2 2 SO3 Type of reaction: double displacement Type of reaction: single displacement Type of reaction: combustion Type of reaction: decomposition Type of reaction: synthesis

CP Chemistry Semester 1 Final Test Review 1. Know the symbol and the power of 10 for the following metric prefixes: A. Mega B.

Mass in grams 10 20 30 40 50 CP Chemistry Semester 1 Final Test Review 1. Know the symbol and the power of 10 for the following metric prefixes: A. Mega B. kilo D. deka E. deci G. milli H. micro C. hecto