Chapter 2 Chem – Flashcards

Something that has magnitude, size or amount.

Measurement

International measurement system

Length Mass Time Temperature Amount of substance Electric Current Luminous Intensity

Meter

Kilogram

Second

Kelvin

Mole

Ampere

candela

10^6

10^3

10^-2

10^-3

10-6

Measure if gravitational pull on matter.

Formed with the combination of SI base units

m2

M3

Kg_m3

Kg_mol

3 dimensional space an object occupies

A ratio derived from the equality between two different units that can be used to convert from one unit to the other.

there must be agreement on meaning amd size of units. standards for units must be un-changing to avoid confusion and ambiguity.

Refers to the closeness of measurements to the correct or accepted value of the quantity measured.

Refers to the closeness of a set of measurements of the same quantity made in the same way.

Is calculated: value accepted-value experimental entre value accepted por 100

In a measurement consists of all the digits known with certainly plus one final digit, which is somewhat uncertain or is estimated.

Zeros appearing between nonzero digits are significant (Example: 40.7=3 sf. 87.009= 5 sf.)

Zeros appearing in front of all nonzero digits are not significant. (Example: 0.095897= 5sf. 0.00009= 1sf.)

Zeros at the end of a number and to the right of a decimal point are significant (Example: 85.00= 4sf. 9.000000000= 10sf.)

Zeros at the end of a number but to the left of a decimal point may or may not be significant. If. A Zero has not been measured or estimated but its just a placeholder, it is not significant. A decimal point placed after zeros indicates that they are significant. (Example: 2000 may have either 1 or four sf depending on how many zeros are placeholders aka 1 sf. 2000. 4sf (because of decimal point)

Examples 3 sf.

Be increased by 1 (Example: 42.68=42.7)

Stay the same (E: 17.32=17.3)

Be increased by 1 (E: 2.7851=2.79)

Increased by 1

Stay the same??

Numbers are written in the form m x 10^n. where the factor M is a number greater than or equal to 1 but less than 10 and n is a whole number.

Two quantities are directly proportional to each other if dividing one by the other gives a constant value.

Two quantities are inversely proportional to each other if their product is constant.

Quantitative: numerical. Qualitative: Descriptive.

A testable statement.

It is more than a physical object, it often explayns why phenomena occurs and how events and data are related.

That a MODEL is more than a physical object, it often explayns why phenomena occurs and how events and data are related, and a THEORY is a broad generalization that explains a body of facts or phenomena.

Standards help avoid confusion and ambiguity when taking measurements. A meter will always be the same length, no matter who is taking the measurement or where it is being taken.

Because the lenght of the day is not a fixed unit of time.

If the accepted value is less than the experimental value.