Chemistry – Midterm Part 3 Material Unit Review packet 2014 ALLEN
1. Label the following as chemical or physical change:
Grass growing_____physical______Dissolving sugar in water____ physical___ Evaporating water__physical____ Na in water appears to dissolve and forms NaOH__chemical__
2. An element is found which is a good conductor of electricity, is ductile, brittle and does not react with acid. Is this new element a metal, nonmetal or metalloid? metalloid
3. The current periodic table is arranged according to increasing____atomic number__.
4. Elements in the same vertical column are in the same group and have similar properties due to similar electron configurations.
5. An element is discovered which bonds to oxygen in a 1:1 ratio. Where would it be placed on the periodic table? ______group 2______
6. Estimate the boiling point of Kr if the boiling point of argon is -186°C and xenon -112°C. (-186+-112)/2 = -149°C
7. Give the characteristics of each group and label the periodic table with their correct positions:
Alkali metals alkaline earth metals noble gases Periods Halogens transitional metals lanthanide and actinide metals Groups or families
Group 1 = alkali metals (+1), highly reactive Group 2 = alkaline metals (+2) , highly reactive but less reactive than group 1 D block = transition metals (varied charges), strong color (pigments) Group 7 = halogens, highly reactive Group 8 = noble gases, unreactive Top row of inner transition metals = lanthanide series Bottom row of “ “ “ = actinide series Periods = horizontal Groups/families = vertical
8.) Balance Equations: _2_H2 + __O2 2__H2O
9.) Define Law of Conservation of Matter Matter can be neither created or destroyed during a chemical reaction.
10.)Physical and Chemical Changes Has the identity of the substance changed? Physical Chemical Examples? Change in state of matter rusting (specific to iron) Melting Oxidizing Evaporation Corrosion Boiling Combustion sublimation Color change freezing ripping dissolving Observations?
11.) Are phase changes such as evaporation/condensation physical or chemical? __physical___How do you know? Change of state, chemical formulas do not change What about melting/freezing? __physical___ Why? Change of state, chemical formulas do not change
12.)Metals, Nonmetals, Metalloids (semi-metals)
Location and Properties on the periodic table metals – left of metalloid line, metalloids – on the staircase, must have a complete side on the staircase (except aluminum), nonmetals – to the right of the metalloid line Do they conduct? Metals Are they malleable or brittle? Metals – malleable nonmetals – brittle Do they react w/ acid? Metals Recall Metal verses Nonmetal lab experience
13.) Arrangement of Periodic Table Families (Groups) – similarities? ___same # of V.E.’s, ______patterns? they react similarly
Rows (Periods) – similarities? e- fill on the same valence energy level patterns? period to period the same patterns will repeat
Mendeleev vs. Modern form – similarities? patterns emerge based on arrangement differences? F block is separate in modern form how arranged? They are both arranged according to increasing atomic number
Noble Gases – properties? Unreactive why? Already have a complete octet
Location of: Alkali metals group 1 alkaline earth metals group 2 halogens group 7
14.) Periodic Trends Number of outermost or valence electrons in groups/families and trends in periods, list trends: Group 1 – VE = 1 (+1) Group 2 – VE = 2 (+2) Group 3(13) – VE = 3 (+3) Group 4 (14) – VE = 4 (+or – 4) Group 5 ( 15) - VE = 5 (-3) Group 6 (16) – VE = 6 (-2) Group 7 (17) – VE = 7 (-1) Group 8 (18) – VE = 8 (0)
Energy level of electrons in outermost shell related to the periods:______period # - outermost energy level______
Relate valence electrons to group characteristics: each element in the group has the same number of valence electrons and will react with other elements similarly.
Relate valence electrons to rows of elements: valence electrons fill into the same valence energy level going across a period
Relate valence electrons to ion formation (most common ionic charge of families): 1st part of number 14
15.) Chemical properties / Physical properties Predicting bonds formed using the locations of elements on periodic table: Metals bonded to nonmetal ionic Nonmetals bonded to nonmetals covalent
What trends exist as we go left to right in a period on the periodic table? Increased density from left to right ( atomic radius decreases going across); electronegativity increases going across
What trends exist as we go down a group on the periodic table? Increases going down a group; electronegativity decreases going down a group
Example: Use the following chemical formulas and the periodic table to predict chemical formulas for compounds containing the pairs of elements. Na2O BCl3 CaCl2 AlF3 1. K and Se 2. Sr and I 3. Ga and Br 4. Al and Br K2Se SrI2 GaBr3 AlBr3
16.) Balancing Equations CO2 + 2NH3 CON2H4 + H2O Coefficients big #’s to the left (can be changed) Symbols chemical symbols of elements Counting atoms Subscripts small #s to the right of the element symbol Formulas NH3 Cannot be changed
18.) Metal Reactivity Use of the activity series “free” metals needs to be above bonded metal for a rxn to occur. Significance of location within the series Will the following reaction happen? Mg + AgCl yes Ag + MgCl2
19.) Redox Reactions LEO GER Define: Oxidation___losing electrons Reduction gaining electrons Oxidizing agent – electron acceptor vs. reducing agent electron donor Write the Half-reactions for: Mg + 2AgCl 2Ag + MgCl2
Oxidation: Mg Mg +2 + 2e- Reduction: 2Ag+1 + 2e- Ag
Write the Oxidizing agent vs. reducing agent for the above reaction. Oxidizing agent – Ag+1 Reducing agent - Mg
20.) Using the following Reaction, identify the terms and answer the following questions:
Ca(s) + 2 H2O(l) Ca(OH)2(aq) + H2(g) Reactants products Identify: Products reactants element Ca and H2 chemical symbol – abbrev. of an element name Subscript coefficient compound H2O and Ca(OH)2 chemical formula – represents the elements in a compound and the relative number of atoms found in that compound.
List the phase of matter for each reactant and product: Ca – solid H2O - Liquid
How many H atoms are in the reactants, the products? Reactants – 4 H atoms Products – 2 H atoms
How would you obtain, purify each product formed by this reaction. In other words, how would you separate the products so you have each alone? Filter the water and Ca (s). Since the calcium is solid it would remain in the filter paper while water passes through.
21.) How does the Law of Conservation of Matter relate to chemical equations? Chemical equations must obey the law of conservation of mass, therefore the amount of atoms of each element must be equal on both sides of the equation.
22.) Balance the following chemical reactions:
6H2O + 4NO 4NH3 + 5O2
2AgNO3 + BaCl2 Ba(NO3)2 + 2AgCl
Use the Metal Reactivity Series for questions 23and 24:
23.) Is silver the best metal for the statue of liberty? Justify your answer: According to THIS activity series, platinum would be the best metal because it is the least reactive.
24.) Predict whether the following reactions will occur:
Yes CuNO3 + Al Cu (s) + Al(NO3)3(aq)
No NaNO3 + Zn -->
25.) Name the layers of the Earth. Which layer provides most of the resources people use? Atmosphere, hydrosphere, (crust, mantle, core) collectively known as the lithosphere
The crust provides the most resources.
26.) Is it more important to recycle renewable or nonrenewable resources? Why?
27.) Identify which of the following reactions is a redox reaction. In each redox reaction, identify:
Substance being oxidized substance being reduced oxidizing agent Reducing agent label charges on each element in the redox reaction
2NaNO3 + BaI2 Ba(NO3)2 + 2NaI Not a redox reaction because there is no transfer of electrons. The charge of each element remained the same during the reaction.
Zn + 2AgNO3 Zn(NO3)2 + 2Ag This is a redox reaction. Charges 0 +1 -1 +2 -1 0 Zn is being oxidized. Ag is being reduced. NO3 is the spectator ion. Zn is the reducing agent. Ag is the oxidizing agent.
28.) Which ions in problem 27 are polyatomic ions? NO3 - nitrate