Chapter 2: Chemistry and Measurements

SI system

In the ________, the temperature is measured using the Kelvin (K) temperature scale, on which the lowest possible temperature is 0 K.

SI unit of length

The metric and ________ is the meter (m)

Conversion Factors

________: Any equality that can be written as fractions; with one of the quantities in the numerator and the other quantity in the denominator.

process of problem solving

The ________ in chemistry often requires one or more conversion factors to change a given unit to the needed unit.

metric system

In the ________, temperature is measured using Celsius temperature.

liter

When a(n) ________ is divided into a thousand parts, each of the smaller volumes is called a milliliter (mL)

Weight

________: The measure of the gravitational pull on an object.

Hydrometer

________: An instrument often used to measure the specific gravity of fluids.

Gram

________ (g) is used for smaller masses.

Density

________: The mass and volume of any object can be measured.

Equalities

________: This shows the relationship between two units that measure the same quantity.

Significant figures

________ (SFs): All the digits including the estimated digit. Nonzero numbers are always counted as ________.

equal portions

When a liter is divided into 10 ________, each portion is a deciliter (dL)

Cubic centimeter

________: The volume of a cube whose dimensions are 1 cm on each side.

Specific Gravity

________: A relationship between the density of a substance and the density of water.

prefix milli

When the ________ is used with the unit meter, it becomes a millimeter, a length that is one- thousandth of a meter (0.001 m)

usefulness of conversion factors

The ________ is enhanced by the fact that we can turn a conversion factor over and use its inverse.

Density

________ can be used as a conversion factor.

The SI unit of mass, the kilogram (kg)

used for larger masses

Step 1

State the given and needed quantities

Step 2

Write a plan to convert the given unit to the needed unit

Step 3

State the equalities and conversion factors

Step 4

Set up the problem to cancel units and calculate the answer

Metric System

A system of measurement used by scientists and in most countries of the world.

International System of Units (SI)

Also known as Système International; the official system of measurement throughout the world except for the United States.

meter

The metric and SI unit of length.

39.4

A meter is______ inches, which makes it slightly longer than a yard.

Density Formula

Specific Gravity Formula

Volume

The amount of space a substance occupies.

Liter

The metric and SI unit of volume

Millimeter (mL)

It is a smaller and more convenient unit of volume, mostly used by chemists at laboratories or hospitals.

Mass

The measure of the quantity of material it contains.

Kilogram

The SI unit of mass; used for larger masses

Gram

The SI unit of mass; used for smaller masses

Temperature

It tells us how hot something is, how cold it is outside, or helps us determine if we have a fever.

Celsius

In the metric system, the temperature is measured using _______ temperature.

Celsius (°C)

On the _______ temperature scale, water freezes at 0 ° and boils at 100 °.

Fahrenheit (°F)

On the ________ temperature scale, water freezes at 32 ° and boils at 212 °.

Kelvin (K)

In the SI system, the temperature is measured using the _____ temperature scale, on which the lowest possible temperature is 0.

atomic clock

The standard now used to determine a second is an _______.

Measured numbers

The numbers you obtain when you measure a quantity such as your height, weight, or temperature.

Significant figures (SFs)

All the digits including the estimated digit. Nonzero numbers are always counted as significant figures.

Exact Numbers

Those numbers are obtained by counting items or using a definition that compares two units in the same measuring system.

Zeros

_____ in front of a decimal number or at the end of a nondecimal number are *not significant*.

4 or less

If the first digit to be dropped is _____, then it and all the following digits are simply dropped from the number.

5 or greater

If the first digit to be dropped is _________, then the last retained digit of the number is increased by 1.

prefix

The special feature of the SI as well as the metric system is that a _________ can be placed in front of any unit to increase or decrease its size by some factor of 10.

centi

When the prefix *______* is used with the unit meter, it becomes centimeter, a length that is one-hundredth of a meter (0.01 m).

milli

When the prefix __________is used with the unit meter, it becomes a millimeter, a length that is one-thousandth of a meter (0.001 m).

Equalities

This shows the relationship between two units that measure the same quantity.

Cubic centimeter

The volume of a cube whose dimensions are 1 cm on each side. It has the same volume as a milliliter, and the units are often used interchangeably.

Conversion Factors

Any equality that can be written as fractions; with one of the quantities in the numerator and the other quantity in the denominator.

equality

An _______ may also be stated within a problem that applies only to that problem.

dosage problems

Equalities stated within _____ for medications can also be written as conversion factors.

percentage

A _________ is written as a conversion factor by choosing a unit and expressing the numerical relationship of the parts of this unit to 100 parts of the whole.

Conversion factors

These are useful when changing a quantity expressed in one unit to a quantity expressed in another unit.

problem-solving process

In the ________, a given unit is multiplied by one or more conversion factors that cancel units until the needed answer is obtained.

Density

The mass and volume of any object can be measured.

Specific Gravity

A relationship between the density of a substance and the density of water.