Chemistry Final- Semester 1

Define Chemistry

Define Chemistry

The study of the composition, structure, and properties of matter (anything with mass and volume) , the changes it undergoes, and energy changes

1. A physical science

2. The CENTRAL SCIENCE

3. A chemical is any substance that has a definite composition.

Which of the following observations is evidence used to imply that a chemical reaction has occurred?

A. Gas production

B. A precipitate forms

C. The colour changes

D. The temperature changes

E. The odor changes

F. A sound is produced

G. A change in taste

Gas production, precipitation formation, colour changes, and temperature change

Physical property

A property that can be observed and measured without changing the material’s composition. Example color, hardness

Chemical property

A property that can only observed by changing the composition of the material.

Examples- ability to burn, decompose, ferment, react with, etc. be

What is the difference between a physical change and a chemical change?

A physical change will change the visible appearance of the material without changing the composition, but a chemical change creates a new form of matter (chemical reaction)

Identify which changes are physical:

1. Boiling water

2. Rusting iron

3. Burning candles

4. Breaking glass

5. Melting wax

Boiling water, breaking glass, melting wax

Identify which changes are chemical:

1. Boiling water

2. Rusting iron

3. Burning candles

4. Breaking glass

5. Melting wax

Rusting iron, burning candles

Classification of Mixtures

Come in Homogeneous and heterogeneous (mixture where things are not easily combined). They can be separated by physical means.

Classification of pure substances

Made up of elements ( a pure substance made of only one kind of atom) or compounds (made of two or more elements that are chemically bonded). Can only be broken down/separated chemically.

Which of the following are elements?

1. Lead

2. Water

3. Kool-aid

4. Table salt

5. Soda

6. Oxygen

Lead, Oxygen

Which of the following are compounds?

1. Lead

2. Water

3. Kool-aid

4. Table salt

5. Soda

6. Oxygen

Water, Table salt

Which of the following are mixtures?

1. Lead

2. Water

3. Kool-aid

4. Table salt

5. Soda

6. Oxygen

Kool-aid, Soda

What are the characteristics of a metal?

1. Good conductors of heat and electric current

2. Tend to be ductile

3. Tend to be malleable

4. Tend to be shiny(luster)

What are the characteristics of a metalloid?

Properties are in between that of metals and nonmetals. Malleable, but dull

What are the characteristics of a non-metal?

1. Tends to be a poor conductor of heat and electric current

2. Tend to be non-ductile

3. Tend to be non-malleable

4. Tend to be dull in color/sheen

Identify each type of element as metal, metalloid, or non-metal:

1. Zn

2. As

3. S

4. Ne

5. Na

1. Metal

2. Metalloid

3. Nonmetal

4. Nonmetal

5. Metal

What are the steps of the scientific method

1. Identify a problem and existing information

2. Come up with a hypothesis

3. Begin Experiment

4. Data & Results

5. Conclusion

What are the rules/guidelines of determining significant figures?

1. Any nonzero numbers are always significant (6.42 m, 3 sig figs)

2. Zeros between nonzero numbers are always significant (230.5 cm, 4 sig figs)

3. In numbers containing a decimal point, all zeros written to the right of the rightmost non-zero digit are significant (78.30 km & 7.000 km, 4 sig figs)

4. Placeholder zeros are not significant (0.0345 g or 4,350 mi, 3 sig figs) Rule 5 - Counting numbers & defined constants have an infinite number of significant figures (15 molecules)

How many sig figs are in 1234?

4

How many sig figs are in 123.0?

3

How many sig figs are in 123400?

4

How many sig figs are in 0.001234?

4

How many sig figs are in 0.01230?

4

What is 1234 in scientific notation?

1.234* 10^3

What is 123.0 in scientific notation?

1.23* 10^2

What is 123400 in scientific notation?

1.234 *10^5

What is 0.001234 in scientific notation?

1.234*10^-3

What is 0.01230 in scientific notation?

1.23*10^-2

What are the common SI units?

Time: second (s) \n Length: meter (m) \n Mass: kilogram (kg) \n Temperature: kelvin (K) \n Amount of substance: mole (mol)

What are the prefixes for SI units?

Kilo; Unit Abbreviation is k; 10³ \n Deci; Unit Abbreviation is d; 10⁻¹ \n Centi; Unit Abbreviation is c; 10⁻² \n Millil; Unit Abbreviation is m; 10⁻³

What is the difference between mass and weight?

Multiply 5.98mm * 3.2mm

Add 3.258cm +12.0cm

15.3

What is a qualitative observation? Example?

Information that describes, color, odor, shape or other physical characteristics. Relatingto the five senses. Example, when something is hot or blue in color

What is a quantitive observation? Example?

Numerical information. Example, temperature, volume, or pressure value.

What is the difference between accuracy and precision?

The former is a measure of how close the quantitative value is to an accepted value (how close in numerical value the two amounts are). \n The latter is a measure of how precise measurements are in comparison to one another (how much the values between each differ).

How many grams of mercury would you have if you had 32 cm3 of mercury? The density of mercury is 13.6 g/cm3.

Ronnie has a piece of aluminum which has a mass of 10.8 grams and a volume of 4 cubic centimeters. Calculate the density of aluminum.

Describe Dalton’s Atomic Theory.

1. All matter is composed of tiny particles called atoms

2. Atoms of a given element are identical in size, mass & other properties

3. Atoms of different elements differ in mass & other properties

4. Atoms cannot be subdivided, created, or destroyed (in ordinary chemical reactions)

5. Atoms of one element can combine with atoms of another element to form "compounds" - new, complex particles.

What did we learn from Rutherford’s Gold Foil Experiment and how did it work?

How it worked: An extremely thin piece of gold foil was bombarded with fast-moving alpha particles. Particles then hit the detecting screen (a piece of film), and are recorded. Rutherford expected the alpha particles to pass through with only slight deflections. Instead, Rutherford discovered that some were scattered at large angles, and others had been deflected back to where they came. \n What was discovered: Rutherford concluded that only a positively charged and relatively heavy target, such as a proposed nucleus, could account for the repulsion. He then concluded that the nucleus is small, dense, and has a positive charge.

What did J. J. Thomson discover with his Cathode Ray experiment?

Thomson concluded that:

1. Cathode rays had identical properties, regardless of the element used to produce them. Thus, elements must have identical (negatively) charged electrons.

2. Atoms are neutral, so there must be positive particles in the atom to balance the negative charge of the electrons.

3. Electrons have so little mass that atoms must contain other types of particles that balance out the total mass of the atom.

Define Atomic number

The number of protons contained within one atom of any given element

Define mass number

The total number of protons and neutrons which make up the nucleus of an isotope.

Define average atomic mass

The weighted average of the atomic masses of all the naturally-occuring isotopes of an element. (i.e. Carbon = 12.011 amu)

Define isotopes

Atoms of the same element which have different atomic masses.

What is the difference between atoms, ions, cations, and anions?

Atom: The smallest particle of an element that retains its identity in a chemical reaction. \n Ion: An atom or group of atoms that has a net positive or negative charge. \n Anion: An ion which carries a net negative charge. \n Cation: An ion which carries a net positive charge.

What is the atomic number, mass number, number of protons, electrons, neutrons, in Br (Bromine)?

What is the atomic number, mass number, number of protons, electrons, neutrons, in Ba^+2 (Barium)?

What is the atomic number, mass number, number of protons, electrons, neutrons, in Cl^-1 (Chlorine)?

What is the atomic number, mass number, number of protons, electrons, neutrons, in Al (Aluminum)?

Which element has 30 protons 35 neutrons, and 30 electrons?

Zinc

An ion of an element has 29 protons, 35 neutrons, and 27 electrons. What ion is this? Write its symbol with the correct charge.

Copper(II) Cu+2

Most of the volume of the atom is taken up by the electron cloud. True or False

False

What are orbitals?

The regions of space around the nucleus of an atom where an electron is likely to be found

Name four orbitals

s, p, d, f

What is the Aufbau principle?

A principle which states that electrons will always want to occupy the lowest level electron shell that is available.

What is the Pauli exclusion principle?

The maximum amount of electrons that an energy level can hold is two- each with a different spin.

What is Hund’a rule?

A single electron with the same spin must occupy each energy orbital before additional electrons with opposite spins can occupy the same orbital. Basically, electrons will not pair up until they have to in terms of occupying orbitals.

What are the properties of waves?

Origin: The base line of the energy \n Crest: The high point of a wave \n Trough: The low point of a wave \n Amplitude: The distance from the Origin to the Crest \n Wavelength: The distance from one Crest to a second Crest

Define electromagnetic radiation.

What are the different types of electromagnetic radiation.

Which elements have an exception to the rule for filling orbitals in their configurations?

Chromium and Copper

What are groups?

Columns in a periodic table

What are families?

Columns in a periodic table

What are the trends for electronegativity?

Decreases down a group and increases across a period

What are the trends for ionic radii?

Increase down a group and increase across a period

What are the trends for atomic radii?

Increases up a group and across a period

What are the trends for ionization energy?

Decreases down a group and increases across a period

Which group of elements are most reactive?

Group 17, Halogens

What are the names of the groups of elements?

Group 1: Alkaline Metals \n Group 2: Alkaline Earth Metals \n Group 3-12: Transition Metals \n Group 13: Boron Group \n Group 14: Carbon Group \n Group 15: Nitrogen Group \n Group 16: Chalcogens/Oxygen Group \n Group 17: Halogens \n Group 18: Noble Gases

What are the transition metals?

Which elements are nonreactive?

Group 18, Noble Gases

How are elements related in a group?

Where are the nonmetals located on the periodic table?

Lie to the right on the zig-zag line except for Hydrogen

What are the properties of non-metals?

What is ionic bonding?

Any chemical bond between elements which involves the transfer of electrons (anions and cations are involved with this type of bond).

What is polarity?

Any uneven distribution of charges in an ionic bond

Is water polar?

Yes

Is CH4 polar?

No

Describe metallic bonding

A bond formed from the attraction between metal atoms & the surrounding "Sea of Electrons"; this is how metal atoms are held together in the solid state. Also, metals hold valence electrons very weakly.

What is an alloy?

A mixture of two or more elements where at least 1 of those in the mix is a metal. It is made by melting a mixture of ingredients, and then cooling to a solid state.

What are the physical properties of metals?

Write the correct formula for the compound made from the ions Na^+1 and Br^- 1. What is the compound name?

NaBr. Sodium Bromide

Write the correct formula for the compound made from the ions Mg^+2 and I^-1. What is the compound name?

MgI2. Magnesium Iodide

Write the correct formula for the compound made from the ions Ca^+2 and N^-3. What is the compound name?

Ca3N2. Calcium Nitride

Write the correct formula for the compound made from the ions Fe^+3 and S^-2. What is the compound name?

Fe2S3. Iron (III) Sulfide

Name the compound for BaO

Barium Oxide

Name the compound for CuF

Copper (I) Fluoride

Name the compound for Cu3P

Copper (I) Phosphide

What is the chemical formula for potassium chloride?

KCl

What is the formula for iron (III) sulfide?

Fe2S3

What is the formula for lithium oxide?

Li3O