F1 Midterm Exam - IS

Unit 1 and Unit 2

Science

The study of phenomena and events in Nature through systematic observation and experimentation

The branches of science

Physics, chemistry, biology, astronomy, geology, medicine

Major natural resources

water, living things, fossil fuels, air, metal ores

Renewable resources

Resources that can be replenished continuously in Nature and will not be used up

Examples of renewable resources

Plants, animals, water, air

Non-renewable resources

Resources that cannot be replenished in a short time once they are used up. Their supply is limited

Examples of non-renewable resources

Fossil fuels, metal ores

Natural resources that are seriously affected by pollution

Water and air

What problems cannot be solved by using scientific knowledge?

Relationships, ethics, wars

Scientific knowledge is subject to ()

change

Steps in a scientific investigation

Observe, form a hypothesis, design and do experiments, analyse, draw a conclusion

Science process skills

observing, classifying, inferring, communicating

Types of scientific investigations

Fair tests, classifying, pattern seeking, model building

Independant variable

The only variable that is changed

dependant variable

The variable to be measured

controlled variables

Variables that are kept the same

Classifying

Comparing the similarities and differences between objects, and sorting those with similarities into groups

Pattern seeking

Observing and recording natural phenomena and trying to find a pattern

Model building

Represent objects that are too small or too big to see

Laboratory safety equipment (4)

Safety goggles, protective gloves, fire blanket, sand bucket

Potential dangers in the laboratory (4)

Should tie up long hair, should wear safety goggles, should not eat or drink, should not leave Bunsen flame unattended

Hazard warning symbols

Flammable, corrosive, explosive, toxic, harmful or irritant

Flammable

Keep away from heat and flame

Corrosive

Wear safety goggles and protective gloves when handling the chemical. Store in a well ventilated room

Explosive

Keep away from heat and flame. Avoid shock

Toxic, harmful, irritant

Avoid breathing in the vapour of the chemical. Wear safety goggles and protective gloves when handling the chemical. Wash your hands thoroughly after handling the chemical

Cuts

Clean the wound with water and apply a dressing to it

Heat burns or chemical burns

Place the affected area under slow running water

Chemicals got into the eyes

Wash the eyes with distilled water from an eye wash bottle

Glass breakage

Clean up broken pieces of glass and dispose of them in a broken glass container

Gas leakage

Turn off the gas supply and open all windows and doors

Fires

Keep calm and report to your teacher at once

Fire triangle

Fuel, oxygen and a high temperature

Using fire beaters

Stop the supply of oxygen

Spraying with water

Lowers the temperature

Cutting down trees

Remove the fuel

How should we read the scale when measuring the length of an object with a ruler

From vertically above

Meniscus

The curved surface of liquid in the measuring cylinder

How should we take an accurate reading of the liquid in the measuring cylinder?

At the bottom of the meniscus

What can we use to measure the mass of an object?

A balance

What can we use to measure the temperature of an object?

Thermometer

How should we take an accurate reading of the thermometer?

Our eyes should be at the same level as the liquid level

What do we usually use to measure time?

A stopwatch

Why do we often repeat the measurement several times and then calculate an average value?

To reduce errors

Ways to transfer solutions

Pouring and using a dropper

Different methods to mix solutions well (2)

Use a glass rod to stir, gently shake the test tube

Luminous flame

Air hole is closed, irregular shape, yellow in colour, lower temperature, quiet

Non-luminous flame

Air hole is open, regular shape, blue in colour, higher temperature, noisy

Strike back

Air hole is fully open, green in colour, high temperature, hissing sound

Physical states of water

Solid, liquid, gas

Solid

Ice

Liquid

Water

Gas

Water vapour

Melting

The change from solid state to liquid state

Melting takes place at a () temperature, what is it called?

fixed, melting point

Melting point

0 degrees Celsius

Does the temperature change during the process of melting?

No

When ice melts, does it absorbs or releases energy?

Absorbs

Freezing

The change from liquid state to solid state

Freezing takes place at a () temperature, what is it called?

fixed, freezing point

Does the temperature change during the process of freezing?

No

The freezing point of water

0 degrees Celsius

When ice freezes, does it absorbs or releases energy?

Releases

Boiling and Evaporation

The change from liquid state to gas state

Boiling takes place at a () temperature, what is it called?

fixed, boiling point

Boiling point of water

100 degrees Celsius

What happens when water is heated to its boiling point?

It changes to steam

Does the temperature change during the process of boiling?

No

When water boils, does it absorbs or releases energy?

Absorbs

Evaporation takes place at () temperature

Any

What happens when water evaporates?

It changes into water vapour

When water evaporates, does it absorbs or releases energy?

Absorbs

Condesation

The change from gas state to liquid state

When does condensation happen?

When water vapour in air comes into contact with cold surfaces

What happens when water vapour in air condenses into water?

Water droplets are formed on the surfaces

When water vapour or steam condenses into water, does it absorbs or releases energy?

Releases

Which two changes of state in water are in the water cycle?

Evaporation and condensation

When does the rate of evaporation increase?

The temperature is higher, the humidity is lower, there is more airflow and the surface area exposed is larger

Solution

When a substance dissolves in a liquid

Solute

The substance that dissolves

Solvent

The liquid in which the substance dissolves

Water

Universal solvent

Soluble

Can be dissolved

Insoluble

Cannot be dissolved

When does the rate of dissolving increase?

The solution is stirred, the temperature of the solvent is higher, the surface area of the solute is larger

Solubility

The maximum amount of solute that can be dissolved an a fixed amount of solvent

What does the solubility of a substance in water change with?

Temperature

What does natural water contain a lot of?

Impurities

Two most common microorganisms found in natural water

Amoeba and E.coli

Methods of water purification

Sedimentation, filtration and distillation

Sedimentation

Large and heavy insoluble impurities sink to the bottom of the container and form a layer of sendiment

Commonly used filters in the laboratory

Filter columns, filter paper

What does filter paper have?

Many tiny pores

Residue

Impurities that cannot pass through the pores and are trapped by the filter paper

Filtrate

Liquid, microorganisms and soluble impurities that passes through

Distillation

The process of boiling and condensing water

What can distillation remove?

insoluble and soluble impurities and microorganisms

Methods to kill microorganisms in water

Chlorination, adding ozone and using ultraviolet light

Disadvantages of chlorination

Toxic and has an irritating smell

Advantages of ozone

Does not have an irritating smell and is more effective in killing microorganisms