Combined Science and Geography Studies

BIOLOGY NOTES ABOUT
Sexually Transmitted Diseases

Sexually transmitted infections (Sit), also known as s*xually transmitted diseases (STDs) or venereal diseases (VD) are diseases that are passed on from one person to another through s*xual contact - the infection can be passed on through vaginal in*******se, oral s*x, and a**l s*x.

Some s*xually transmitted infections can spread through the use of unsterilized drug needles, from mother to baby during childbirth, or breast-feeding, and blood transfusions.



Examples of s*xually transmitted diseases include:

· chlamydia

· cancroid

· crabs (p***c lice)

· ge***al herpes

· ge***al warts

· hepatitis B

· human immunodeficiency virus and acquired immunodeficiency syndrome (HIV and AIDS)

· human papillomavirus (HPV)

· trichomoniasis (parasitic infection)

· pelvic inflammatory disease (PAID)

· syphilis, gonorrhoea

· trichomoniasis (trich)



Chlamydia

Also known as chlamydial infection, chlamydia is an STI caused by Chlamydia trachomatis (C. trachomatis), a bacterium that infects humans exclusively. Chlamydia is the most common infectious cause of ge***al and eye diseases globally - it is also the leading bacterial STI.



Women with chlamydia do not usually have signs or symptoms. If there are any, they are usually non-specific and may include:

· cystitis

· a change in vaginal discharge

· mild lower abdominal pain



If chlamydia is left untreated, it may lead to the following signs and symptoms:

· pelvic pain

· painful s*xual in*******se, either intermittently or all the time

· bleeding between menstrual periods



Chancroid

Chancroid is also known as soft chancre and ulcus molle. It is a bacterial infection caused by fastidious gram-negative streptobacillus Haemophilus ducreyi and is characterized by painful sores on the ge***als. It is only spread through s*xual contact.



Infection rates are very low in

CHEMISTRY NOTES ABOUT
Acids, Bases and Salts

Acids

Acids are solution of non-metallic oxides. When oxides of non-metals dissolve in water, they form acids. Other acids occur naturally in plants and animals. Examples include tartaric acid in grapes, citric acid in lemons and acetic acid in vinegar.



Making acids

Simply dissolving oxides of non-metals in water,

Examples;

1. Carbon dioxide a gas dissolves in water to form carbonic acid

2. Sulphur dioxide a gas dissolves in water to form sulphurous acid

3. Sulphur trioxide a white that solid dissolves in water to form sulphuric acid

4. Nitrogen dioxide a brown gas, dissolves in water to form nitric acid



Bases

Bases can be made in one of two ways

1. by dissolving oxides of metals in water e.g. magnesium oxide dissolved in water to give magnesium hydroxide which is a base, or

2. by adding water to reactive metals e.g. when you put sodium in water it reacts to form sodium hydroxide. Another metal which can be used is potassium.



Properties of Acids and Bases



Acids

Bases

1

Has a sour taste (never taste it)

Has a bitter taste and slippery feel between fingers

2

Turns blue litmus paper red

Turns red litmus paper blue

3

They are corrosive

Some bases are caustic

4

Reacts with base to form salt and water

Reacts with acid to form salt and water

5

Turn universal indicator yellow, orange or red

They turn universal indicator green, blue, purple

6

They react with metals to produce salt and hydrogen





Neutralisation and the formation of salts

Neutralisation is a chemical reaction between an acid and a base. An acid and a base will neutralize each other. In this chemical reaction, the hydrogen in an acid is replaced with a metal to form a salt and water.



Formation of Salts

Salts can be formed in one of the following ways;



The pH scale

pH - a value used to express the acidity or alkalinity of a solution.

The term pH originates from the French words pou

Fuel Engines

An engine is a device that converts chemical energy in fuel to kinetic energy to do work. E.g. moving a car

Chemical energy (in fuel) Kinetic/Mechanical energy

How the fuel engine operates

· Petrol engines have two main sections, the cylinder section and the carburetor.

· The action of the pistons in the cylinders converts chemical energy into kinetic energy and

· The carburetor supplies the cylinders with a petrol- air mixture to each cylinder.

· Most vehicles have at least four cylinders in their engines.

· The advantage of multiple cylinders is that the engine will run more smoothly and will be more powerful.

There are four strokes in a petrol engine for each cylinder.

The intake/inlet stroke

· The pistons move down

· The intake/ inlet valve is opened

· The petrol air mixture enters the cylinder from the carburetor

· The exhaust valve is closed

The compression strokeBoth valves are closedThe piston moves upwards to compress the petrol air mixtureThe power strokeBoth valve are closedA spark is produced by the spark plug and sets fire to the petrol air mixture (ignition)The mixture explodes and forces the pistons downIt is during this stroke when chemical energy is converted to kinetic energy causing the car to move. The piston will rotate the crankshaft, which in turn will rotate the wheels through the gear box.The exhaust strokeThe exhaust valve is openedThe inlet valve is closedThe pistons move upwards forcing the exhaust gases out of the cylinder.

Illustration of 4stroke engine

CHEMISTRY
INDUSTRIAL PRODUCTION
we summarise the Industrial Processes by the term
S.A.N
C.H.O
V.I.P
O.N.A
S.H.O
this term stands for
S.A.N {specific name for acid}
Sulphiric acid ☆Ammonia acid ☆Nitric acid

C.H.O{specific name for process}
Contact Process☆ Harber Process ☆Oxidation Process

V.I.P {catalyst}
Vanedium (v) Oxide ☆ Iron fillings☆Platinum/Rhodium

O.N.A{Raw materials}
Oxygen ☆Nitrogen ☆Ammonia

S.H.O{Raw materials}
Sulphur ☆Hydrogen ☆Oxygen

Respiratory Systems of human being