Measurements

Measurements

an integral part of science and consists of a number and a unit

Measurement

A _ is a collection of quantitative or numerical data that describes a property of an object or event. It is made by comparing a quantity with a standard unit.

Error

Since this comparison cannot be perfect, measurements inherently include _, which is how much a measured value deviates from the true value.

Scientists

they typically make a repeated measurement of a quantity to ensure the quality of their findings and to know both the accuracy and precision of their results

Precise

Measurements are said to be _ if they yield very similar results when repeated in the same manner

Accurate

A measurement is considered _ if it yields a result that is very close to the true or accepted value

Precise Value

_ value agreed with each other

Accurate Value

_ value agreed with the true value

Unit Conversion

_ are important in chemistry because many calculations use different units of measurement and using conversion factor, we can convert one unit to another desired unit

Conversion Factor

A _ is a ratio or fraction which represents the relationship between two different units

100 cm

Length: 1 meter is what in cm?

1 in

Length: 2.54 cm is what in in?

1 cm

Length: 10 mm is what in cm?

1 km

Length: 1000 m is what in km?

1000 mL

Volume: 1L is what in mL?

1 L

Volume: 1000 cm³is what in L?

1 kL

Volume: 1000 L is what in kL?

4 quarts

Volume: 1 gal is what in quarts?

2 pints

Volume: 1 quart is what in pints?

1000 L

Volume: 1 m³ is what in L?

1000 g

Mass: 1 kg is what in g?

1000 mg

Mass: 1 g is what in mg?

1 lb

Mass: 453.6 g is what in lb?

16 oz

Mass: 1 lb is what in oz?

2000 lbs

Mass: 1 short ton is what in lbs?

2240 lbs

Mass: 1 long ton is what in lbs?

1000 kg

Mass: 1 metric ton is what in kg?

2.20462 lbs

Mass: 1 kg is what in lbs?

Dimensional Analysis

it is an approach in solving problems of measurements

Dimensional Analysis

It is the analysis of the relationships between different physical quantities by identifying their base quantities and units of measure and tracking these dimensions as calculations or comparisons are performed

Dimensional Analysis

it is a technique of converting between units

Fundamental (primary/basic) Units

_ are all those units of the Metric System which are independent of any other unit (including themselves); they can be determined even without using formulas

Derived (secondary) Units

_ are all those units of the Metric System which are derived or obtained by multiplying and/or dividing multiple fundamental units and sometimes with other constants, in short, they cannot be measured directly

Fundamental (primary/basic) Units

Example are:

• mass

• length

• temperature

• volume of liquid

Derived (secondary) Units

Some examples are:

• density

• area

• volume

Mass

_ is the quantity of matter in a particular sample of matter.

Mass

_ is constant regardless of where it is being measured.

True

True or False

If the same material is being measured, say, the mass of the material, it is the same whether you measure it on the moon or here on Earth.

Weight

_ is the gravitational force of attraction between the body’s mass and the mass of the planet where it is being measured

Length

it is simply measured with a ruler or a meterstick

Volume of a Liquid

_ is measured in a graduated cylinder, pipette, volumetric flask, etc.

Volume of a Regular Solid

_ is determined by measuring its dimensions and multiplying them together.

Volume of an Irregular Solid

the _ is determined using the water displacement method.

Water Displacement Method

In the _, the amount of space taken by the object is the volume of the object

Density of the Substance

_ is the relationship between the mass of the substance and how much space it takes up (volume).

density of a substance

The mass of the atoms, their size, and how they are arranged determine the _

Formula of Density

Density = the mass of the substance ÷ by its volume; D = m/v

Formula of Volume

Volume = the mass of the substance ÷ by its density ; V = m/d

Temperature

_ is the degree of hotness and coldness of a body measured using a thermometer.

Formula of Celsius scale (°C)

°C = 5/9 (°F – 32)

Formula of Fahrenheit Scale (°F)

°F = 9/5 (°C) + 32

Formula of Kelvin Scale (°K)

K = °C + 273

Specific Gravity

_ is the ratio between the density of an object and a reference substance

1g/mL

Usually, the reference substance is water which always has a density of _

Specific Gravity

Density is directly related to the mass of the object (unit is usually in grams), so the _ can also be determined by dividing the mass of the object by the mass of water

Specific Heat

_ is the amount of heat necessary to raise the temperature of a given amount of substance by one degree Celsius

Specific Heat

_ is important as it will indicate how much energy will be required to heat or cool an object of a given mass by a given amount