Chapter 1 & 2 Test Flashcards
Scientific Notation
a x 10* 1 ≤ a ≤ 10 * = # of decimal places moved * > 0 if decimal moves left *< 0 if decimal moves right
Scientific Notation Steps
- Move the decimal until there is ONLY 1 number to the left of the decimal
- Write this number down (but don’t include any unnecessary zeros) followed by “x 10 *” where * is the # of decimal places moved
Significant Digits
The # of digits that are known with certainty plus 1 that is uncertain
Rules For Counting Significant Digits
- All nonzero figures are significant
- All zeros between nonzero figures are significant
- When a decimal point is shown, zeros to the RIGHT of the nonzero figures are significant
- Zeros to the left of the first nonzero are not significant (add decimal if needed)
Rules for Adding and Subtracting Significant Digits
The final answer must have the same number of DECIMAL PLACES as the measurement with the LEAST # of DECIMAL PLACES
Rules for Multiplying and Dividing Significant Digits
The answer should contain no more SIGNIFICANT DIGITS than the measurement with the FEWEST # of SIGNIFICANT DIGITS
Rules for Rounding Off
- If the first digit to be dropped is <5, the PRECEEDING digit stays the
- If the first digit to be dropped is >5, the PREECEDING digit is increased by 1
- If the first digit to be dropped is 5 followed by only zeros, ROUND UP if the PRECEEDING number is ODD (483.5 —> 484) and LEAVE it the same if it is EVEN (482.5 —> 482)
Precision
Refers to the exactness of a measurement (the greater the number of significant digits —> the greater the precision
Accuracy
Refers to how close a given quantity is to an accepted value
Dimensional Analysis
A method of calculation in which both numbers and units are carried through the algebraic operation
Conversion factor
Ratios (fractions) comparing 2 units
Atom
The smallest particles of an element that still retains the identity and properties of an element
Atomic Number (Z)
Number of PROTONS in the nucleus of the atom of the element
Mass Number (A)
Total number of PROTONS and NEUTRONS in the nucleus
To determine the number of neutrons, simply subtract the atomic number from the mass number
(mass number — atomic number = # of neutrons)
Standard Atomic Notation
Mass number A Ion charge
X
Atomic number Z Subscript
(# of atoms in compound)
Structure of Atom
The atoms of each element are electrically neutral
→ in the neutral atom of any element, the # of protons = the # of electrons
→ electrons occupy the space surrounding the nucleus and are responsible for the chemical properties of the element
Dalton’s Atomic Theory of Matter
- All matter is made up of tiny particles called atoms. An atom cannot be created, destroyed or divided into smaller particles
- The atoms of one element cannot be converted into the atoms of another element
- All the atoms of one element share the same properties (mass and size). These properties are different for each element
- Atoms of different elements combine in specific proportions to form compounds
Modern Atomic Theory of Matter
- All matter is made up of tiny particles called atoms. Each atom is made up of smaller subatomic particles: protons, electrons, and neutrons
- The atoms of one element can be converted into the atoms of any other element by a chemical reaction called nuclear fusion
- All the atoms of one element share the same properties (mass and size). These properties are different for each element
- Atoms of different elements combine in specific proportions to form compounds
Ion
A positively or negatively charged particle that results from a neutral atom or group giving up or gaining electrons
Physical Properties
Description of matters
Qualitative Physical Properties
Describes the physical properties of a substance
EX: physical state, colour, odour, crystal shape, malleability, ductility, hardness, brittleness
Quantitative Properties
Involves measurement using accepted units
EX: melting point, boiling point, density, solubility, electrical conductivity, thermal conductivity
Chemical Properties
Properties of a substance we observe when matter is converted into different kinds of matter
Ex: reactivity with water, air, pure oxygen, acids, pure substances, combustibility (flammability), toxicity, decomposition
Physical State
The condition of being a solid, liquid, or a gas