C_TAKS_Chemistry_Review

C_TAKS_Chemistry_Review - Cypress Creek HS Cypress TAKS...

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Unformatted text preview: Cypress Creek HS Cypress TAKS Objective 4: TAKS Structure & Properties of Matter Structure A Quick Density Review Quick ratio of mass to volume high density: a lot of mass in a small high volume volume Density of water is 1 g/mL Density = mass =m Density volume v Evaluating Density Evaluating Compare Compare the mass, volume and density of sample A and B below. below. What would happen What to the density of B if the sample were cut in half? in FIGURE Figure 1 1 A A B B Mass, Volume, and Density Mass, FIGURE Figure 1 1 A A MA < __ MB VA __ VB < A B DA __ DB = B B A block of maple wood with a volume of block 405 cubic centimeters and a density of 0.67g/cm3 is sawed in half. The density of the two smaller blocks is now. the A One-fourth the original density B One-half the original density C Two times the original density D The same as the original density Evaluating Density How How does the density of the Diet Coke compare to that of the Coke? Explain. to If the density of water is 1 g/mL, then what can you infer about the density of each can of soda? The table shows some properties The of four different substances. The picture shows a solid picture sphere of one of the four sphere substances in a water-ethanol solution (D = 0.9199 g/mL). The sphere is most likely composed of which substance? of A Substance Q B Substance R C Substance S D Substance T D = 0.9199 g/mL The The instruments below show the mass and volume difference of an irregularly shaped object. Using the data, the density of the object is ____________. A 25.4 g/mL B 4.40 g/mL 4.40 C 0.019 g/mL 0.019 D 5.24 g/mL Answer Explanation Answer • Recall, Density = Mass/Volume Here, the mass is shown on the balance as 22 g. The volume of the irregular-shaped object must be found The by using the water displacement method. The initial volume of water reads 20.0 mL and the final volume of water reads 25.0 mL. Subtract the final volume by the initial volume to determine the volume of the object, 5.0 mL. mL. D = M/V = 22 g/5.0 mL = 4.40 g/mL. Therefore, answer M/V choice B is correct. choice This This pipette is filled with a 20% NaOH solution. The solution is at 20°C and has a density of 1.23 g/mL. According to this information, what is the mass of this NaOH solution? solution? A 3.88 g 3.88 D =m 1.23 g = _m_ B 15.7 g 15.7 1v 1 mL 19.4 mL C 23.9 g 23.9 m=1.23g x 19.4mL = 23.9 g D 24.6 g 24.6 1 mL Answer is C Two Two scientists decided to compare the densities of a crown and a block of metal. The scientists found the volume of the block and computed its density based on its known mass (2,400 g). The diagram below shows the dimensions of the block of metal that the scientists measured. What is the density of the block of metal? the Answer: ____________ g/cm3 Answer Explanation Answer D = M/V The mass is given in the problem; The M = 2400 g. 2400 To determine the volume of the box: To V = length x width x height V = 5 cm x 5 cm x 5 cm = 125 cm3 D = 2400 g/125 cm3 = 19.2 g/cm3 PERIODIC TABLE PRACTICE PRACTICE Another tool for success on the Another test. test. Atomic Number (# of protons or electrons) Element Symbol Atomic Mass (Average mass of all isotopes) + ++ ++ + + ++ + + ++ + 14 Si 28.086 Silicon Element Name The Periodic Table #protons identifies the element #p = #e, for neutral atoms Periodic Table Rows are called “periods.” PERIODS 1 2 3 4 5 6 7 This is period number 3. The elements in this row have their electrons located in 3 energy levels. Columns on the periodic table are called “groups” or “families.”The groups are numbered from “families.”The 1-18. 1 18 13 14 15 16 17 2 3 4 5 6 7 8 9 10 11 12 This is group 1. Families have similar but not identical physical and chemical characteristics Chemical Properties Chemical Groups: Groups: have similar chemical and physical properties properties Metals vs Nonmetals Metals: •Form (+) ions Nonmetals: •Form (­) ions •Lose/donate electrons •Gain/accept electrons •Combine/react with nonmetals •Combine/react with metals The The bonding characteristics of oxygen are most similar to the bonding characteristics of — characteristics A B C D hydrogen silicon helium sulfur A certain atom has a nucleus containing certain six protons and eight neutrons and has six electrons orbiting the nucleus. This atom is a form of the element — is A silicon B carbon C magnesium D calcium valence electrons: valence # electrons in the outermost energy level. Determined by the ones place NOT the 10’s place in the group number. place 18 1 2 13 14 15 16 17 + ++ ++ + + ++ + + ++ + Label Your Periodic Table Label CIRCLE THE GROUP NUMBERS CIRCLE Groups = Similar Chemical Properties = Valence Practice Using Your Periodic Table Practice An An isotope of which element has an atomic number of 7 and a mass number of 15. A. Nitrogen A. C. Phosphorus B. Oxygen D. Magnesium Practice Using Your Periodic Table Practice The The table shows the electron configuration of which neutral atom? of ELECTRON CONFIGURATION A. Sodium B. Phosphorus B. C. Nitrogen C. D. Arsenic Energy Level 1 2 # Electrons 2 85 3 Practice Using Your Periodic Table Practice An An element from group 2 on the periodic table would bond easiest with an element from which other group? from A. 4 B. 13 C. 14 D. 16 Chemical & Physical Properties Chemical Chemical The ability or The inability of matter to chemically react with other matter with Physical Measurable Observable by our Observable 5 senses senses Classifying Matter Classifying Element Element Compound Contains one type of atom, Contains found on periodic table found 2 or more elements or chemically combined. Chemical formula. Chemical Mixture elements and/or elements compounds that are physically combined and different materials are visible. visible. Solutions are homogenous Solutions mixtures mixtures H2O Chemical vs. Physical Changes Chemical Chemical Change Atoms Atoms chemically combine in a new way combine Represented by a Represented chemical reaction chemical Observations: Observations: Color change Temperature change Gas produced Solid formed Physical Same Same Change combination of atoms atoms Observations: Observations: Change Change in shape, size or location or Change in phase Ratios in Chemical Formulas Ratios A chemical formula is a combination of element symbols and subscripts that tells you the ratio of elements. (LabAids Inc.) Examples: H2O = 2 atoms H to 1 atom O 2H:1O atoms Fe2O3 = 2 atoms Fe to 3 atoms of O 2 Fe : 3 O Fe *NaCl = 1 atom Na to 1 atom Cl 1 Na : 1 Cl *NaCl Na *For NaCl, the ratio is 1:1 because Na is a Group 1 element with 1 valence electron (loses 1e-) and Cl is a element Group 17 element with 7 valence electrons (gains 1e-). Group The ionic compounds that results from combining Group The 2 and Group 16 elements have a 1:1 ratio because— A B C D Group 2 elements are electrically neutral. Group 2 elements have two valence electrons. Group 2 elements contain neutrons in the nucleus. Group 2 contains more elements than other groups. Elements Elements from Group 1 on the Periodic Table will form compounds with elements from Group 15. An example would be potassium phosphide (K3P). A compound with elements from these (K P). two groups will always combine with a ratio of __Group 1 : __Group 15. A B C D 6:2 2:6 1:3 3:1 Conservation of Mass Conservation Both sides of a chemical reaction must have the same Both mass: mass reactants = mass products. mass: 2HgO 2Hg + O2 10g 9.3g + ? 10 g = 0.7 + 9.3 g ...But what happened to the O2? This is the Law of the Conservation of Mass – Matter is neither created nor destroyed. According to the law of conservation of mass, how much According zinc was present in the zinc carbonate? zinc A 408 g B 256 g C 104 g D 40 g Is mass conserved? Is H2O H2 + O2 What do we need to do? To be balanced, there must be the same number of atoms To of each element on both sides of the equation. of 2H2 + O2 2H 2H2O Reactants: Products: 4H 4H 2O 2O Practice balancing the following chemical equations. chemical __Al + __O2 __Al2O3 __Al __C2H4 + __O2 __CO2 + __H2O __C __Zn(NO3)2 + __Na2CO3 __ZnCO3 + __NaNO3 __Zn(NO Good Luck! Good Make good use of your periodic table and Make formula chart! formula Get a good night sleep. Study the night before, your brain will Study continue to process while you sleep. continue ...
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