1. A substance that cannot be broken down or decomposed by a chemical change. 2. A substance whose atoms all have THE SAME ATOMIC NUMBER.
Where are all the Elements found?
How many capital letters do their symbols have?
ONLY 1 capital letter.
Which of the following substances CANNOT be decomposed by chemical change? (1) sulfuric acid (2) ammonia (3) water (4) argon
Which substance CANNOT be decomposed by a chemical change? (1) mercury (II) oxide (2) potassium chlorate (3) water (4) copper
A substance that is composed only of atoms having the same atomic number is classified as (1) a compound (2) an element (3) a homogeneous mixture (4) a heterogeneous mixture
(2) an element
What are Diatomic Elements?
Elements whose molecules consist of 2 atoms in nature.
What are the 7 Diatomic Elements?
I₂, Br₂, Cl₂. F₂, O₂, N₂, H₂ ( I Brought Claire From Our New House)
What are Monatomic Elements?
Elements whose molecules consist of 1 atom in nature.
Everything on the Periodic Table except the 7 Diatomic Elements.
What are Compounds?
A substance than can be decomposed into simpler substances by chemical means including electrolysis.
What are Compounds? (cont.)
A substance made up of 2 OR MORE elements chemically combined in a fixed ratio.
What are Compounds? (cont.)
ALL chemical formulas of compounds have at least 2 capital letters & are NOT found on Table S.
All compounds are..
Which substance can be decomposed by a chemical change? (1) ammonia (2) aluminum (3) magnesium (4) manganese
Which substances CAN be decomposed chemically? (1) CaO and Ca (2) MgO and Mg (3) CO and Co (4) CaO and MgO
(4) CaO and MgO *Look for compounds, 2 cap letters.*
A COMPOUND differs from a MIXTURE in that a compound always has a..
Which substance CAN be decomposed by chemical means? (1) aluminum (2) octane (3) silicon (4) xenon
Which substance CAN be broken down by chemical means? (1) magnesium (2) manganese (3) mercury (4) methanol
Tetrachloromethane, CCI₄, is classified as a..
Compound because the atoms of the elements are combined in a fixed proportion.
Which list of formulas represents COMPOUNDS ONLY? (1) CO₂, H₂O, NH₃ (2) H₂, N₂, O₂ (3) H₂, Ne, NaCI (4) MgO, NaCI, O₂
(1) CO₂, H₂O, NH₃
Which type of matter is composed of TWO or more elements that are chemically combined in a fixed proportion? (1) solution (2) compound (3) homogeneous mixture (4) heterogeneous mixture
Which substance CAN be broken down by chemical change? (1) CO (2) Ce (3) Ca (4) Cu
Every water molecule has TWO hydrogen atoms bonded to ONE oxygen atom. This fact supports the concept that elements in a compound are..
(1) Chemically combined in a fixed proportion.
What are Binary Compounds?
A compound consisting of 2 elements (2 capital letters).
What are the Common Binary Compounds?
NaCI = salt H₂O = water NH₃ = ammonia CH₄ = methane SiO₂ = sand
Which formula represents a Binary Compound? (1) NH₄NO₃ (2) CH₄ (3) CH₃COCH₃ (4) CaCO₃
Which is a binary compound? (1) sodium chlorate (2) silver nitrate (3) potassium chloride (4) ammomium sulfide
(3) potassium chloride
An example of a binary compound is (1) mercury (2) ethanol (3) sodium (4) ammonia
What are Ternary Compounds?
A compound consisting of 3 elements (3 capital letters).
A mixture can be separated by..
Mixtures can be _______ or _______
Homogeneous or Heterogeneous.
Mixture are always in a _______ ratio. The atoms of the elements combine in a ratio that _____.
-A varying ratio. -A ratio that varies.
A mixture is NOT a..
A HOMOgenenous mixture is anything that dissolves in..
Anything that dissolves in water is a..
Homogeneous mixture. **Look for (aq) = acqueous**
Homo Mixtures: The composition is the ______ throughout and all of the particles are ______ distributed.
-SAME -EVENLY distributed.
Another word for a homogeneous mixture is a..
Examples of Homo Mixtures:
Kool-Aid,Salt Water, Sugar Water, Iced Tea, etc.
Hetero Mixtures: The composition is ____________ throughout from top to bottom, and the particles are ____ distributed.
-NOT the same. -UNEVENLY distributed.
Examples of HETERO mixtures:
Sand & salt, oil & water, pizza, Italian dressing, rocky road icecream, etc.
One similarity between a COMPOUND & a MIXTURE:
They both consist of 2 OR MORE substances.
4 Differences between a COMPOUND & a MIXTURE:
BROKEN DOWN-- HOW? Compounds are broken down _________. Mixtures are broken down ___________.
HOMO, OR HETERO? Compounds are ____, Mixtures can be ____ or ____.
Compounds are HOMO. Mixtures can be HOMO or HETERO.
FIXED OR VARIED? In a compound, the elements combine in a ____ ratio. In a mixture, they combine in a _____ ratio.
-Fixed ratio. -Varying ratio/ratio that varies.
PURE, OR NOT? Compounds are a ___ substance. Mixtures are NOT.
Which statement is an identifying characteristic of a mixture? (1) A mixture can consist of a single element. (2) A mixture can be separated by physical means. (3) A mixture must have a definite composition. (4) A mixture must be homo.
(2) A mixture can be separated by physical means.
Which pair are classified as chemical substances? (1) mixtures and solutions (2) compounds and solutions (3) elements and mixtures (4) compounds and elements
(4) compounds and elements
Which represents a homogeneous mixture? (1) CuSO₄(s) (2) Br₂(l) (3) NaCI(aq) (4) CO₂(g)
Which formula represents a mixture? (1) C₆H₁₂O₆(l) (2) C₆H₁₂O₆(s) (3) LiCI(aq) (4) LiCI(s)
Liquids that mix with each other are..
Miscible. EX: Water & Alcohol.
Liquids that do NOT mix with each other are..
Immiscible. EX: Oil & Water.
METHODS OF SEPARATING A MIXTURE.
Separating a solid from a liquid, using filter paper.
Filtration separates different parts of a mixture by their _______________.
Solubilities & molecular polarities.
Flitration is only used to separate __________________ mixtures.
Anything that is insoluble in water will ____ on the filter paper & ______ pass through it.
-COLLECT. -WILL NOT PASS.
Any particles that are dissolved in solution, will _____ through any filter.
NaCI(aq) and SiO₂(s) can be separated using a..
Funnel and filter paper.
Method of separating dissolved particles (such as salt) from water.
Method of separating 2 OR MORE MISCIBLE liquids with different boiling pts./mole. polarities.
Petroleum can be separated by distillation because the hydrocarbons in petroleum are..
Compounds, with different boiling pts.
A beaker contains BOTH alcohol & water. These liquids can be separated by distillation b/c the liquids have different..
All homo mixtures to separate depending of the diff. parts of the mixture having diff. attractions to the paper due to their diff. solubilities & mole. polarities.
Used to separate immiscible liquids. EX: Oil & Water.
Any element/comp in the solid, liquid, or gas state. EX: H₂O(l), O₂(g), NACI(s)
Mixtures (aq) are ________ substances.
Are NOT pure.
Any property that DOES NOT change the chemical nature of matter.
EX: Density, color, boil/melt/freeze pt, odor, taste, solubility, ability to dissolve in water, electrical conductivity.
Any property that gives a a substance the ability to undergo a change that results in a NEW substance.
EX: Ability to REACT with an acid, base. Combustible/Flammable, ability to decompose.
PHYS OR CHEM?
The boiling point of lithium is 1615 K
Iron combines with oxygen to form rust
Potassium REACTS with iodine to produce po6tassium iodide
The density of calcium is 1.54g/cm³
Helium gas compresses
Selenium melts at a temp of 494 K
Sodium conducts electricity & heat
Zinc reacts w/ acid to produce hydrogen gas
Tin can be flattened into sheets
Salt dissolves in water to form
Magnesium burns in air
The chemical composition of a substance is NOT changed.
**If you see the SAME substance on BOTH SIDES of the arrow in a chem equation, it's a physical change. WITH THE EXCEPTION OF SALT DISSOLVING IN WATER. EX: H₂O(s)+heat = H₂O(l) CO₂(s)+heat = CO₂(g)
When adding/subtracting sig figs, first line up the decimal points. Solve the problem, then cross out any columns to the RIGHT of the decimal point that have an empty space in it. Round. 162.1g + 38.73g + 1.554g = 202.4 44.7 kg - 7.2 s = 2.7
Mult. & Dividing Sig Figs
For mult. & div. sig figs, first find the # of sig figs in EACH # being multiplied or divided. Solve the problem. The answer to the problem MUST have the SAME 3 OF SIG FIGS AS THE 3 WITH THE LEAST AMT OF SIG FIGS.
Mult. & Dividing Sig Figs Examples
23.6(3 sig figs) x 6.2(2 sig figs) = 146.32 → 150 198.6 ÷ 22.4 = 8.86607 → 8.87
I kiloJoule = 1,000 Joule
1 kJ = 1,000J KJ TO J = 3 PLACES TO RIGHT. J TO KJ = 3 PLACES TO LEFT.
Q = mc∆T Q= heat m= mass c(Table B) = specific heat capacity ∆T= change in temp.
**When reading a heat problem, & you notice a CHANGE IN TEMP, then you KNOW to use Q= mc∆T.
How much heat is required to raise the temp of a 26-gram sample of water by 35°C?
Q=mc∆T → Q= (26)(4.18)(35) → 3.803 Joules
How much heat is necessary to change the temp of 17-grams of water from 10°C to 25°C?
Q=mc∆T → Q= (17)(4.18)(15) → Q= 1065.9 Joules
SOLVING FOR MASS. (Q=Mc∆T) If 8300 Joules of heat raises the temp of a sample of water by 36°C, what is the MASS of the water?
8300 =M(4.18)(36) 8300/ 150.48 → M = 55.2g
SOLVING FOR INITIAL TEMP. When solving for initial temp., first solve for ∆T, then SUBTRACT ∆T from the temp given in the problem.
SOLVING FOR FINAL TEMP. When solving for final temp., first solve for ∆T, then ADD ∆T to the temp given in the problem.
HEAT OF FUSION (Q= mHf)
-The amount of heat required to change one gram of a substance from a SOLID TO A LIQUID. -The heat of fusion for water is 334J/g.
HEAT OF FUSION PROBLEMS
**When you see 0°C & NO OTHER TEMP, or the word melts, freezes, melting/freezing pt, solid to liquid or liquid to solid.** -How much heat is required to MELT 66 grams of ice at 0°C?
HEAT OF VAPORIZATION (Q = Mhv)
Amount of heat required to change one gram of a substance from a LIQUID TO A GAS. The heat of vaporization of water is 2260 J//g.
HEAT OF VAPORIZATION PROBLEMS
**When you see 100°C & NO OTHER TEMP, or the terms -Vaporize, condense, boiling pt, liquid to gas, or gas to liquid.** USE Q = Mhv -How much heat is required to vaporize 39 grams of water at its BOILING POINT?
**There is more heat required to vaporize the sample in heat of vaporization than in heat of fusion.
-Definite shape & volume. -Particles are arranged in a regular/definite geometric pattern. -The particles are tightly packed closely together. -Particles are constantly vibrating b/c they're so tightly packed. -Solid state has strongest IMF.
Indefinite shape, but DEFINITE VOLUME. -Takes the shape of the container. -Liquids have STRONGER IMF than gases, but WEAKER IMF that solids.
-Indefinite shape AND indefinite volume. -Takes the shape & COMPLETELY FILLS THE CONTAINER. -Gas state has the weakest IMF.
(TABLE S) If the temp of a element is BELOW the melting point of that element, it's in the SOLID STATE.
(TABLE S) If the temp of an element is between the melting pt & boiling pt of that element, it's in the LIQUID STATE.
(TABLE S) If the temp of an element is ABOVE the boiling pt. of that element, it's in the gas state.
(TABLE S) (C°? Add 273.) Copper at 2012 K = Liquid Germanium at 980°C = Liquid Hydrogen at 24 K = Gas Gold at 925°C(add 273) = solid
Draw 6 molecules of chlorine as they would appear at -53°C in the box below? Chlorine is diatomic. -53 +273 = 220 K
Endothermic. SOLID→GAS The three main substances that sublime are: -H₂0(s), CO₂(s), & I₂(s)
-For a substance to sublime, it must have HIGH VAPOR PRESSURE, & WEAK IMF of attraction.