Exam 1 Review Flashcards
Classify the basic forms of matter.
Solid, liquid, gas.
Identify the types of pure substances.
Elements and compounds.
Physical property.
Observed without changing the composition or identity of a substance.
Physical change.
Produces a recognizable difference in the appearance of a substance, without causing any change to its composition.
Example of physical changes (simple).
Phase change
What are examples of physical properties?
Conductivity, boiling point, density, temperature, volume, solubility.
What are examples of chemical properties?
Flammability, oxidation state, acidity.
Define intensive properties.
Properties of matter that are independent of quantity.
Examples of intensive properties.
Color, melting point, boiling point, don’t ask me about density.
Examples of extensive properties.
Mass, volume.
Define extensive properties.
Properties of matter that are dependent on the quantity.
Significant figure rules.
All nonzero digits are significant. Zeros located between nonzero digits are significant. Trailing zeros are significant if the number has a decimal point. Zeros to the left of the nonzero digit are insignificant.
Significant figure rules in addition/subtraction.
The result cannot have greater significance than any of the quantities that produced the result.
Accuracy
Degree of agreement between the true value and measured value.
When adding or subtracting in scientific notation…
Convert both numbers to standard form.
Significant figure rules in multiplication/division.
The result should have the same amount of significant figures as the number with the least significant figures.
Conversion between Celsius and Fahrenheit.
F = 1.8 x C + 32
Precision
Degree of agreement between all measures values.
Density formula.
d = m / v (g/ml or g/L)
Define specific gravity, give the formula.
Specific gravity is the ratio of the density of a substance to the density of water.
Specific gravity =
density of object / density of water
What element is most present in the human body?
Oxygen.
Groups vs. Periods
Groups are vertical! Periods are horizontal.
A neutral atom has…
The same number of electrons and protons.
Atomic number (Z).
The number of protons in an atom.
Mass number (A).
Sum of the protons and neutrons in an atom.
The letter for the atomic number is…
Z
The letter for the mass number is…
A
Define isotopes.
Atoms of the same element with different numbers of neutrons, therefore a different mass number.
Do isotopes have identical chemical properties?
Yes.
Atomic mass is the…
Weighted average of all the isotopes of a specific element.
Steps to find atomic mass, given mass number of isotopes and percentages.
- Convert percentages to decimals (e.g. 75.77% –> 0.7577)
- Multiple the decimal by the mass of the associated isotope (e.g. 0.7577 x 35 = 26.5)
- Do this for all the given isotopes.
- Add them all together!
Dalton’s Atomic Theory (postulates).
- TRUE All matter is made up of atoms.
- An atom cannot be created, destroyed, or converted to another kind of atom.
- Atoms of a particular element have identical properties.
- TRUE Atoms of different elements have different properties.
- TRUE Atoms of different elements combine in simple, whole-number ratios to form compounds.
- TRUE Chemical change involves joining, separating, or rearranging atoms.
What postulates are still regarded as true?
1,4,5,6.
What experiment provided proof of electrons?
Cathode-ray.
What experiment provided proof of the nucleus?
Gold-foil.
Law of Conservation of Mass.
In a chemical reaction, matter is neither created nor destroyed. The total mass of the substances involved does not change.
Law of Definite Proportions
All samples of a given compound have the same proportions of their constituent elements.
Law of Multiple Proportions
When two elements form two different compounds, the masses of the constituent elements can be expressed as a ratio of whole numbers.
Elements of the same… have similar properties.
Group.
Metals tend to…
lose electrons.
Nonmetals tend to…
gain electrons.
Metalloids have…
properties intermediate between metals and nonmetals.
The properties of metals are…
Solid at room temperature, highly malleable, conductive. Form CATIONS.
The properties of nonmetals are…
Solid or gas at room temperature, brittle, nonconductive. Form ANIONS.
Elements on the periodic table are arranged according to…
Atomic number.
The Octet Rule
Elements usually react in such a ay to attain the electron of the closest noble gas; elements on the right side of the table move “forward”, and elements on the right side of the table move “backwards.” Based on PERIOD.
The Octet Rule is very helpful when…
Predicting the charges of ions.
A mole contains…particles.
6.022 x 10^23
