# Terms for Chapter 2

Système International d'Unités

SI.

Second

The base unit for time.

Meter

The base unit for length.

Kilogram

The base unit for mass.

Kelvin

The base unit for temperature.

Mole

The base unit for amount of a substance.

Ampere

The base unit for electric current.

Candela

The base unit for luminous intensity.

273

°C+___=K

Derived unit

A unit that is defined by a combination of base units.

Volume

The space occupied by an object.

Cubic meter

The derived SI unit for volume.

The cubic meter

A large measurement for volume that is very difficult to work with.

Liter

A unit of measurement for volume that is more useful than the derived SI unit of cubic meters. It is equal to one cubic decimeter.

Density

A physical property of matter defined as the amount of mass per unit volume.

D=m/v

The equation to find density.

Scientific Notation

An efficient way for scientists to express very large or very small numbers.

Smaller

The decimal moves right.

Bigger

The decimal moves left.

The same

In order to add or subtract numbers written in scientific notation, the exponents must be ___ ____.

Different

In order to multiply or divide numbers written in scientific notation, the exponents are allowed to be _________, and they are also allowed to be the same.

Multiply the coefficients and add the exponents.

To multiply numbers written in scientific notation,

Divide the coefficients and subtract the exponent of the divisor from the exponent of the dividend.

To divide numbers written in scientific notation,

9.2g

Any number raised to the power of zero is equal to 1, so that 9.2 x10^0 g =

Dimensional analysis

A systematic approach to problem solving that uses conversion factors to move, or convert, from one unit to another.

Conversion factor

A ratio of equivalent values having different units.

Value

Multiplying a quantity by a conversion factor changes its units without changing its

Introduce a new unit

A conversion factor used in dimensional analysis must cancel one unit and

Cancel

When working through a solution, all of the units except the desired unit must

1 km/ 1000 m and 1000 m/ 1 km

The conversion factors for the relationship 1 km=1000 m are:

Accuracy

How close a measured value is to an accepted value.

Precision

How close a series of measurements are to one another.

Error

The difference between an experimental value and an accepted value.

error

Experimental value- accepted value=

Percent Error

Expresses error as a percentage of the accepted value.

percent error

⌊error⌋ ÷ x100accepted value

Significant figures

Include all known digits plus one estimated digit.