UNIVERSITY OF SAN CARLOS

AN EXPERIMENT REPORT ON THE PREPARATION AND PROPERTIES OF

OXYGEN AND HYDROGEN

Report submitted in partial fulfilment of the CHEM 1L subject of Miss Denniell Hurboda (Laboratory Instructor).

ALVAREZ, ROS VINCENT P.

BS-ChE 1

2013

ABSTRACT

The common gases, oxygen and hydrogen are very abundant in the earth’s crust yet it’s

mysteries as gases as a whole had eluded scientists for centuries. Its properties had only become

apparent upon the scientific revolution of the techniques or methodologies with the labouring of

known physicists and chemists of their time.

This experiment focuses on the identification of the properties of our atmosphere’s

common gases (oxygen and hydrogen) and its preparation in the laboratory. It utilized the

experimental type in which it used laboratory equipment to answer the statements of the

problem. The study used the observable results to quantify and analyse the properties of the

gases presented in the equations and the tables or diagrams.

Based on the results, the hypothesis was proven correct and the problem was given a final

conclusion where the processes involved and the properties of the gases became clear.

CHAPTER I

INTRODUCTION

Background of the Study

There are different gases in the atmosphere. There is nitrogen, oxygen, argon, hydrogen,

and helium which constitute most of the earth’s atmosphere. There are of course a lot more but

they are no more than 1% of the entirety. Since the force of gravity pulls down on the masses of

these gases, the heavier gases are typically found near the surface of the Earth (e.g. oxygen)

while the lightest ones (e.g. hydrogen) are found in higher altitudes.

Oxygen is the most abundant element in the earth’s crust and is the third most abundant

element in the universe - one which plays a very important role in our everyday life. It makes up

nearly 21% of the earth's atmosphere and accounts for nearly half of the mass of the earth's crust,

two thirds of the mass of the human body and nine tenths of the mass of water. Oxygen is a

highly reactive element and is capable of combining with most other elements. It is required by

most living organisms and for most forms of combustion.

Composed of a single proton and a single electron, hydrogen is the simplest and most

abundant element in the universe but unlike oxygen, it is seldom found free in nature. It is

estimated that 80% of the visible universe is composed of hydrogen. Hydrogen combines with

other elements to form numerous compounds. Some of the common ones are: water (H2O),

ammonia (NH3), methane (CH4), table sugar (C12H22O11), hydrogen peroxide (H2O2) and

hydrochloric acid (HCl).

A Brief in History

The eighteenth century would be the Century of Gas Chemistry, marked by the discovery

of most of the common gases. Ingenious techniques with which to generate, collect and study

gases were invented at that time. Despite these substantial laboratory accomplishments, the

actual chemical identities of these gases remained complete mysteries until the very end of the

century.

The philosophers of classical Greece were the first to seek knowledge for its own sake.

They attempted to develop a comprehensive philosophy that explained all aspects of the material

world. Around 350 BC, Aristotle was emerging as one of the most brilliant scholars of the time.

He was interested in a wide variety of thoughts and ideas and his influence on subsequent

thought was widespread. Unfortunately for the development of chemistry as a theoretical

discipline, Aristotle rejected the earlier ideas of Democritus that substances were built from

small, indivisible particles called atoms, and built on the ideas of Empedocles, who felt that all

matter was composed of some combination of earth, air, fire, and water. Aristotle broadened

Empedocles' four elements so that earth represented the solid state, air represented the gaseous

state and water represented the liquid state. Every substance consisted of primary matter,

impressed with form, which was the hidden cause of the properties of the substance. The four

forms were hot, dry, moist and cold and the relationship between the forms and elements is

shown here:

Diagram 1

The relationship between the forms and elements of Aristotle

Thus, water (representing all liquids) was cold and moist, air was hot and moist, fire was

hot and dry, and earth (representing all solids) was cold and dry. Every substance on earth was

some combination of the four elements. During transformations, the primary matter was

unaltered but the form was changed. Aristotle's stature among scholars was such that for twenty-

one centuries after his death he was still widely regarded as the ultimate authority on matters of

science. Even though his theory did little to explain much of the physical world, there was no

better theory and few felt they could question the ideas of Aristotle.

The Renaissance brought great advances in chemistry and the development of

experimental methods and scientific thought. Some of these advances involved gases. In the 17th

century Robert Boyle conducted his now famous experiments on physical properties of gases and

combustion. He was outspokenly critical of Aristotle's four element theory and proposed his

own. Although Boyle's theories regarding the nature of substances were vague and not very

accurate (for example, he believed that fire was a particle), he was one of the most prominent

experimentalists to attack Aristotle's theory of the elements. He noted that hydrogen, which he

called 'factitious air’ was highly flammable. It is significant and noteworthy that he was the first

scientist to collect a gas in a vessel.

From Aristotle to our modern scientists, the properties of the gases have been gradually

unveiled. The mysterious nature of gases — their invisibility, their lack of color and odor —

have made them subjects of fascination for generations of chemists. Equipment to study gases

has ranged from simple to complex. In the eighteenth century the experiments were done by the

pneumatic chemists. By the late nineteenth century, chemistry textbooks described methods for

student use. The experiments called for pneumatic troughs and elaborate equipment.

Experiments were time-consuming and noxious gases were generated in quantities that were

often potentially dangerous. Over time, we have learned to produce and study a variety of gases,

safely contained within manageable syringes or set-ups. Each gas takes no more than five

minutes to generate and is immediately available for use in numerous simple experiments. From

university professors to high school students, these simple methods have enhanced our

understanding of gases.

Statement of the Problem

The purpose of this experiment is to investigate the preparation and properties of oxygen

and hydrogen. It sought to answer the following questions:

i. How is oxygen gas generated in the laboratory?

ii. Does copper react with oxygen?

iii. Is hydrogen gas formed when zinc metal reacts with hydrochloric acid solution?

iv. What are the observable characteristics of hydrogen when it is exposed to flame?

v. Based on the findings of the experiment, what conclusions or generalizations can be

derived from the investigation?

Hypotheses

If hydrogen peroxide is allowed to further react using a known catalyst, oxygen will be

generated and will react to copper.

If zinc metal reacts with hydrochloric acid, hydrogen gas is formed and will react with

oxygen.

Significance of the Study

This experiment is important because it allows an in-depth view and investigation of

some of the properties of a few of the common elements that are found in our universe. Time has

taught us on how theories and concepts that are not validated and are lacking scientific

investigation have led to erroneous perceptions that can affect and misguide understanding and

analysis. It is a story, in which the behaviour of matter eventually allowed the genius of man to

first theorize the principles of modern science as we know them even to this day.

CHAPTER II

EXPERIMENTAL DETAILS AND METHODOLOGY

Research Design

The study utilized the experimental method of research in which it used laboratory

materials and equipment to answer the statements of the problem and the relationship in between

variables.

Research Instruments

The materials and apparatus used in the experiment are as followed: syringe (2 ml);

plastic micro spatula; micro burner; a box of matches; bamboo splint; glass tube (6cm x 4mm); a

set of combo plate with lids for connectors; safety glasses; two pieces silicon tubes (4cm x

4mm); combo plate; box of matches; PVC tube with v-bend (5cm x 22mm); gas collecting tube

with lid; large sample vial; lids for combo plate; thin propette; two (2) pieces plastic micro

spatulas; 6 M HCl hydrochloric acid; 3% hydrogen peroxide H2O2; Manganese dioxide powder

MnO2, Copper wire; Zinc powder;

Experimental Procedures

Oxygen Part 1

Three (3) micro spatulas of manganese dioxide were added to a well to be labelled as ‘A’.

1.0 mL of 3% hydrogen peroxide solution was obtained using a calibrated syringe and a drop of

the solution was added into the well labelled ‘A’. A bamboo splint was lit and placed above the

well. Observe the heat glow on the bamboo splint. The procedures were repeated this time using

an empty well.

Figure 1

Oxygen gas generation

Oxygen Part 2

Three (3) micro spatulas of manganese dioxide were again added to a well to be labelled

as ‘A’ and a second well labelled ‘B’ was filled with tap water. Insert two silicone tube

connectors with both ends of the glass tube with a copper wire inside. Install the others ends of

the silicone tube connectors to both the lids’ tube inlets, securing them into place. We obtained

1.0 mL of 3% hydrogen peroxide using the syringe. The syringe nozzle was inserted into the

syringe inlet of the lid labelled ‘B’. We slowly added a drop of hydrogen peroxide and waited for

bubbles to appear on well ‘A’. The micro burner was lit and the flame was brought to the

position where the copper wire was placed and heated it for about five (5) minutes. Observe.

Figure 2

Complete experimental set-up

Hydrogen

A micro spatula of zinc powder was into a well labelled as ‘A’. A lid was fastened to well

A with v-bend PVC rubber tubing inserted into the lid’s gas inlet. A container filled with water

was prepared with the other end of the PVC tube placed in the surface of the water. A gas

collecting tube was placed partially submerged enclosing the opening of the PVC rubber tubing

with its opening facing the bottom of the container. We obtained hydrochloric acid using a

syringe and we slowly added a drop of the solution into well A. Bubbles are first allowed to pass

through before collecting hydrogen gas. When sufficient hydrogen gas was obtained, we

collected it by closing the gas collecting tube’s cover. A matchstick or micro burner was lit and

the gas collecting tube was positioned horizontally with the opening to the flame’s direction.

With the thumb, the lid was opened when the flame became very small with the mouth of the

collection tube directed to the flame. The properties of the gas or gas in general were noted.

Figure 3

Hydrogen gas generator

Hydrogen Generation Demonstration

The laboratory instructor constructed a similar set-up to the first one but it utilized zinc

metal and not zinc powder. First, a cylindrical vessel containing hydrochloric acid was prepared

and anchored into a wooden base to act as support for the container. Second, the zinc metal was

placed in a test tube (large enough to fit into the opening of the hydrochloric acid container) with

an opening at its bottom to allow acid contact with the zinc metal. A glass tube connected to the

test tube facilitated the direction of the evolving hydrogen gas after the reaction between zinc

and hydrochloric acid, later of which was lit for the gas to act as the fuel for the combustion

process. Last was covering the flame with a beaker. Observations were noted.

CHAPTER III

RESULTS AND DISCUSSION

Oxygen Part 1

Bubbles were formed in the well labelled ‘A’ which indicates a chemical reaction took

place and a gas was released. The heat glow on the bamboo splint continued illuminating when

exposed to the well with MnO2 and H2O2. This continued to happen because of the production of

oxygen gas (see Figure 3 below) which is an important component in most combustion

processes. The MnO2 in this experiment is the catalyst that accelerated the evolution of oxygen

gas from H2O2 that also produced water.

2H2O2 2H2O + O2 (aq) (s) (aq) (g)

Figure 3

The evolution of oxygen gas from hydrogen peroxide

Description/s:H2O2 MnO2 H2O O2

Clear liquid Dark fine-particle solid substance

Clear liquid; Water

Colourless, odourless,

tasteless gas

Table 1

Reactant-Product Descriptions

Oxygen Part 2

The heated copper wire looks darker than usual after heating the glass tube when the well

with manganese dioxide was added with hydrogen peroxide. This change in colour is actually

just a coating of a new substance called CuO or rust which is the expected product of this

reaction (see figure 4). Some dark particles were also observed near the reacted substance.

2Cu + O2 2CuO (s) (g) (s)

Figure 4

The production of rust with the exposure of a metal (copper) to oxygen

Description/s:Cu O2 CuO

Brown lustrous metal Colourless, odourless, tasteless gas

Flaky solid dark substance

Table 2

Reactant-Product Descriptions

Copper is not a very reactive metal but when it is exposed to oxygen, a very slow

chemical reaction occurs. The heat here is the catalyst which speeds up the reaction by giving

enough energy for the reaction to occur.

Hydrogen

Bubbles were observed after adding a drop of hydrochloric acid in well labelled ‘A’ to

the well labelled ‘B’ which again is an indicator that a chemical reaction took place and a gas

was released. A zinc chloride salt solution and hydrogen gas is expected to be produced given

the balanced chemical equation in Figure 5 below. When the gas collected after its evolution was

exposed to the flame, it suddenly ‘popped’ and the flame was sustained. This indicates that the

hydrogen gas reacted with the oxygen upon exposure to the flame which proves that the gas is

flammable.

Zn + 2HCl ZnCl2 + H2

(s) (aq) (aq) (g)

Figure 5

The production of hydrogen gas with the reaction of a metal (zinc) to hydrochloric acid

Description/s:Zn HCl ZnCl2 H2

Greyish powder Colourless liquid Clear liquid; Salt solution

Colourless, odourless,

tasteless gas

Table 3

Reactant-Product Descriptions

Hydrogen Generation Demonstration

In the hydrogen generation process, lighting the gas (hydrogen) produced a yellow

(slightly orange) flame which proved it to be flammable. The fuel interacts with oxygen through

combustion that sustains it while releasing heat as a by-product. The hydrogen gas is the fuel in

this combustion process and its interaction with oxygen in return, produces water in the form of

vapour which causes the fog when the lit evolving gas was covered with a beaker. See Figure 4

2H2 + O2 2H2O (g) (g) (g)

Figure 4

The production of water vapour with the combustion of hydrogen with oxygen

CHAPTER IV

CONCLUSIONS

Oxygen gas can be created in the laboratory by liberating oxygen atoms in hydrogen

peroxide with an acceleration of a known catalyst manganese dioxide to the chemically-reacting

solution. Copper will react to oxygen given enough time or with the help of a catalyst such as

heat. Meanwhile, hydrogen can also be created in the laboratory after the chemical reaction of

zinc metal to hydrochloric acid with which was also proven to be flammable after exposure to

flame.

Summary of the properties of the gas produced

OXYGEN HYDROGEN

-a primary component of combustion -is flammable

-a tasteless, odourless, colourless, and a very

abundant gas

-a very light gas

-produced in considerable amounts during the

oxygen generation experiment

-produced in quick and great amounts in the

generation process

Table 1

The common gases

Bibliography

Anderson, M. P.; Mattson, B.; Mattson, S. A brief history of the study of gas chemistry (4th

edition). Educational Innovations: Norwalk, Connecticut, 2006.

Villanueva, J. C. 7 January 2010. Gases in the atmosphere. Retrieved from

http://www.universetoday.com/49849/gases-in-the-atmosphere/#ixzz2bQsNCIz5 on 7

August 2013.

The Element Oxygen. Retrieved from http://education.jlab.org/itselemental/ele008.html on

7 August 2013.

The Element Hydrogen. Retrieved from http://education.jlab.org/itselemental/ele001.html

on 7 August 2013.

Early Chemistry and Gases. Retrieved from http://www.chemheritage.org/discover/online-

resources/chemistry-in-history/themes/early-chemistry-and-gases/index.aspx on 7 August

2013.