Chemistry

Fundamental

- one expression (length)

How many significant figures are in 37,300 grams? A. 2 B. 3 C. 5 D. 6

B. 3

Fundamental scientific measurements.

SI unit Abbreviation length. meter. m Mass(weight. kilogram kg Temp. Kevin k Time. second. s Amount. mole. mol Light intensity. candela. cd Electric current. Ampere. A.

metal

form cations

mass number

indicated the mass of the atom

counting significant figures nonzero integers are always significant

- 3456 ? - 7.35 ?

alkaline earth metal

- beryllium Be - Magnesium Mg - Calcium Ca - Strontium Sr - Barium Ba - Radium

name ionic compounds

- consist of charged particles (ions) formed by transfer of electrons between atoms - ions held together by electrostatic forces ex: LiF: lithium fluoride , LiCI- Lithium chloride, NaCI- sodium chloride

Hypothesis

- educated guess A tentative and testable explanation for an observation or series of observation

accuracy

- how close a measurement is to the true value - agreement between a measured value and accepted value.

precision

- how reproducible is the measurement - agreement between repeated measurement

counting significant figures Zeros

- leading zeros are not significant - 0.0392 ? - 0.000004563 ? - trailing zeros are not significant unless they come after a decimal point. - 3700. ? - 140.00 ? - captive zeros are always significant - 16.07 ? -20.007 ?

compound

- pure substance composed of two or more elements bonded together in fixed proportions - can be broken down into individual elements by chemical reactions

pure substance

- same chemical and physical properties throughout -cannot be separated into simpler substances by physical process

name covalent molecules

-are made from bonding at least two nonmetals and have an electronegativity difference of less than 2.0, meaning they share electrons.

molar mass

-the mass (in grams) equal to the mass of an individual atom or molecule (in amu) -the mass (in grams) of one mole of the substance (atom, molecule, or formula unit) -the molar mass (M) of He is 4.003 g/mol

What is the mass of 4.76 10^20 molecules of the hydrocarbon octane (C8H18)?

0.0903 g

If 3.423 g of aluminum sulfate are present in 1.00 x 10 2 mL of the solution, what is the sulfate ion concentration? Formula unit mass for Al2(SO4)3 is 342.3 g/mol.

0.300 M

Ozone (O3) reacts with iodide (I^-) and water to form iodine (I2), hydroxide (OH^-), and oxygen (O2). Balance the following reaction equation and report the stoichiometric coefficient for O3 and I^-, respectively (O3 first and I^- last).

1, 2

Fe2O3(5) and powered aluminum can react with great output of heat to form molten iron and AI2O3. When this reaction equation is balanced, what are the stoichiometric coefficients in the following order: Fe2O3, AI, Fe, AI2O3?

1,1,1,1

Three states of matter

1. solids 2. liquid 3. gases (vapors)

Ammonia undergoes combustion to produce nitrogen monoxide and water, both as gases. Write the balance equation for this reaction and report the stoichiometric coefficients for ammonia and O2, respectively ( list ammonia first and O2 last).

2, 5

How many mL of commercial HCI (12.0 M) should you use to prepare 240.0 mL of 0.10 M HCI?

2.0 x 10^-3 L

How many atoms of chlorine are there in 25.0 g of calcium chloride (CaCI2)?

2.71 10^23 atoms

In one analysis, the density of ozone in an air sample was found to be 5.00 10^-8 mol/L. what is the density in a molecular per liter?

3.01 10^16

How many hydrogen atoms are in a 346 g sample of pure ammonia (NH3)?

3.67 10^25 atoms

Ammonium nitrate, when heated, decomposes into nitrogen gas, oxygen gas and water vapor. What is the coefficient of water in the balanced equation?

4

In a sample containing 4 moles of N2 gas and 2 moles of O2 gas, how many moles of NO2 gas can be created?

4 moles of NO2

What is the total number of atoms in 1 mole of aluminum iodide?

4 x 6.022 x 10^23

How many oxygen atoms are in 27.0 g of sodium sulfate (Na2SO4)?

4.58 10^23 atoms

The acid-base reaction between phosphoric acid, H3PO4, and calcium hydroxide, Ca(OH)2, yields water and calcium phosphate. For each mole of calcium phosphate produced by this reaction, how many moles of water are produced?

6

In one analysis, 2.01 x 10^16 molecules of carbon dioxide (CO2) were found in 2.00 mL of an air sample. How many moles of oxygen atoms is this?

6.67 10^-8 mol

A sample of water (H2O) contains 1.81 10^24 molecules. How many total moles of atoms are in this sample?

9.00

What is the molar mass of sulfuric acid (H2SO4)?

98.1 g/mol

scientific theory

A general explanation of widely observed phenomena that has been extensively tested and validated

How many moles are in 78.0 grams of zinc?

A. 1.19 moles

Which compound has a molecular mass of 180 amu? A. C6H6 B. table sugar C. C9H8O4 D. C2H2

A. C6H6

Which of the following molecular compounds has both a correct formula and is named correctly? A. CO2, Monomarbon dioxide B. C2O, carbon monoxide C. SO2, Sulfer dioxide D. N2O4, Nitrogen tetraoxide E. SO, Monosulfur monoxide

C. SO2, Sulfer dioxide

condensed structural formula

CH3-CH2-CH3 based of the structural formula

which of the following is a non electrolyte? CH3COOH NaCI CH3CH2OH NaNO3

CH3CH2OH

A boiling water reactor is cooled and moderated similar to a pressurized water reactor though at a lower pressure (7 megapascal). A steam-water mixture moves through the reactor core, absorbs heat, and exits at 545 F. What is this temperature in kelvin? A. 576 K B. 285 K C. 818 K D. 558 K

D. 558 K

How many oxygen atoms are in Ca(NO3)2? A. 2 B. 3 C. 5 D. 6

D. 6

Which compound is named correctly? Assume the formulas are correct. A. Na3P; sodium phosphate B. CaBr2; calcium dibromide C. Cu2O; copper(II) oxide D. Fe2(SO4)3; iron(III) sulfate

D. Fe2(SO4)3; iron(III) sulfate

Some molecular compounds are non electrolytes because they:

Do not form ions in water

molecular formula

Ex: C6H12O6 C4H10 C8H18

name ionic compounds containing polyatomic ions

Ex: hydroxide (OH-), nitrate (NO3-), Nitrate (NO2-), acetate (C2H3O2- or CH3COO-)

formulas used to describe compounds

H represents one atom H2 represents two atoms

formulas for ionic compounds must always be neutral

Mg^2+ + (CI-)x2 MgCI2

which of the following is a strong base? AI(OH)3 Ca(OH)2 NH3 H2SO4

NH3

Components of the Scientific Method

Observation, hypothesis, prediction, Experiment, support hypothesis, = theory, reject hypothesis= scientific scrap heap

molecule

a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.

Avogadro's law

a statement that under the same conditions of temperature and pressure, equal volumes of different gases contain an equal number of molecules.

ion

an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

metalloid

an element whose properties are intermediate between those of metals and solid nonmetals or semiconductor. Ex; chemical element, boron, semiconductor, arsenic, silicon, selenium, antimony, germanium

lanthanide

any of the series of 15 consecutive chemical elements in the periodic table from lanthanum to lutetium. (atomic number 57-71)

actinide

any of the series of fifteen metallic elements from actinium (atomic number 89) to lawrencium (atomic number 103) in the periodic table. they are all radioactive, the heavier members being extremely unstable and not of natural occurrence.

matter

anything that has mass and takes up volume.

transition element

are elements having a partially filled d or F sub shell in any common oxidation state. Elements: copper, iron, silver, titanium, zinc

isotope

atoms of the same element having different numbers of neutrons

Mixture

combination of two or more substance at no specific mixing ratio Two types: homogenous &heterogenous mixtures

homogenous mixture

components are distributed uniformly throughout the sample and have no visible boundaries or regions - components mix evenly

coefficient

constant term related to the properties of a product. the number that always stays the same. -proportions of reactants and/or products - on macro scale, indicate number of moles of each substance.

physical change examples

cutting string, crumpling paper, melting ice, evaporating water water melting "a piece of metal exposed to the elements turns rusty"

solid

definite shape and volume

neutrons

electrically neutral subatomic particles

nonmetal

form anions - charges on ions depend on location in the periodic table. examples: group 1 metals = +1 group 2 metals = +2 halogens = -1

atomic number

indicated the number of protons

anion

ions with negative charge

cation

ions with positive charge

exothermic reaction

is a chemical reaction in which less energy is needed to break bonds in the reactants than is released when new bonds form in the products. ex: rusting of iron, reaction between water and calcium chloride

endothermic reaction

is a chemical reaction in which more energy is needed to break bonds in the reactants than is released when new bonds form in the products. ex: melting ice cubes, melting solid salts, sublimation of dry ice into carbon dioxide gas.

stoichiometry

is a section of chemistry that involves relationships between reactants and/ or products in a chemical reaction to determine desired quantitative data.

mole

is a unit for a specific quantity of a substance - a mole is Avogadro's # of atoms in exactly 12 grams of carbon-12

polyatomic ion

is an ion composed of more than one atom. Example: sulfate ion (SO4^2-) the hydroxide ion (OH-), the hydronium ion (H3O^+)

percent composition

is the percent by mass of each element in a compound. it is calculated in a similar way, % by mass = mass of element mass of compound x 100%

noble gas

key properties: stable, colorless, odorless, inert - Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)

halogen

low melting and boiling points they are also in group 7, on the right - Fluoride (F), Chlorine (CI), Bromine (Br), Iodine (I), Astatine (At)

electron

negative charge

Gases (vapor)

neither definite shape nor volume: expands to fill its container.

Avogadro's number

number of units in one mole of a substance, equal to 6.02214076 x 10^23.

Liquids

occupies definite volume, but flows to assume the shape of its container

period

on the periodic table: they are on the horizontal row

group

on the periodic table: they are the vertical columns

isotopes

one or two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties

perform quantitative measurements measuring devices

part 1- number part 2 - scale (unit) example: 164.2 grams 6.02 x 10^23 atoms/mol

Proton

positively charged subatomic particles

nucleus

protons and neutrons

plum-pudding model

shows an atom that had a positively charged medium, or space, with negatively charged electrons inside the medium.

formula unit

smallest. electricity neutral unit of an ionic compound

ions

some compounds consist of positively or negatively charged particles

oxidation state

sometimes referred to as oxidation number, describes the degree of oxidation (loss of electrons) of an atom in a chemical compound

atomic weight

the average mass of the isotopes of an element

heat of reaction

the change in the enthalpy of a chemical reaction that occurs at a constant pressure. it is a thermodynamic unit of measurement useful for calculating the amount of energy per mol either released or produced in a reaction.

heterogeneous mixtures

the components are not distributed uniformly and may have distinct regions of different composition - components do not mix evenly

One mole is defined as

the number of particles equal to the number of atoms in exactly 12 g of carbon-12.

Atom

the smallest object that retains the properties of an element. Atoms are composed of electrons and a nucleus

formula weight

the sum of the atomic weights of all atoms appearing in a given chemical formula. generally applied to a substance that does not consist go individual molecules, such as the ionic compound sodium chloride

Derived measurement

two or more expressions - volume (l x w x h) - density (g/mL)

daltons atomic theory

was the first complete attempt to describe all matter in terms of atoms and their properties - all matters are made up of indivisible and indestructible particles called atoms. - all atoms of given element are identical in both mass and in particles - compounds are formed when atoms of different elements combine in the ratio of small whole number - compounds are composed of definite arrangements of atoms, and chemical change occurs when the atoms are rearranged