What is the scientific term for energy transferred due to temperature difference?
Power
Work
Heat
Light
Which material is a poor conductor of heat?
Aluminum
Copper
Silver
Plastic
What causes sea breeze during the day?
The land heats faster than the sea
The land cools faster than the sea
The sea and land heat equally
The sea heats faster than the land
Why is adding food coloring to water not a chemical reaction?
Because it changes color
Because it is irreversible
Because no new substance is formed
Because it forms a new substance
Which of the following is a physical change?
Turning milk into yogurt
Melting of wax
Burning of bread
Rusting of iron
What is the state when two systems reach the same temperature?
Thermal expansion
Thermal equilibrium
Thermal radiation
Thermal conduction
How is heat transferred along a metal rod?
By evaporation
By radiation
By conduction
By convection
What is thermal conductivity?
The ability to reflect heat
The ability to transfer heat through a material
The ability to absorb heat
The ability to store heat
What happens in a chemical reaction at the molecular level?
Atoms are created
Atoms remain unchanged
Atoms are destroyed
Atoms are rearranged
Which of the following is a good thermal conductor?
Wood
Cardboard
Why are cooking pot handles made of plastic or wood?
They are good conductors
They are strong
They are good insulators
They are cheap
When 30°C metal balls are mixed with 20°C water, why is the final temperature not 25°C?
Because the mixture has the same specific heat
Because the mixture has the same mass
Because the mixture is made of substances with different masses and specific heats
Because the mixture is not stirred
How is heat transferred from a heater to a thermometer?
Conduction only
Convection only
Radiation only
All three methods
Why does ice melt faster on some materials?
Due to shape
Due to higher thermal conductivity
Due to thickness
Due to color
How is heat transferred in a vacuum?
Not transferred
When iron is exposed to moist air, it undergoes:
Dissolving
Evaporation
Rusting
Melting
What happens when two systems at different temperatures come into contact?
Heat flows from the hotter system to the colder system
Heat flows from the colder system to the hotter system
Both systems become colder
No heat flows between them
Why is the heating coil placed at the bottom of an electric kettle?
To heat water by radiation
To heat water by conduction
To reduce electricity use
To heat water by convection
What is the definition of heat?
A type of radiation
A form of matter
The mass of an object
Energy transferred due to a temperature difference
When hydrochloric acid is added to magnesium, it produces:
Hydrogen
Nitrogen
Oxygen
Carbon dioxide
The browning of an apple after cutting is considered:
A chemical reaction
A change of state
A physical change
What is thermography used for?
Detecting sound
Detecting heat radiation
Measuring volume
Measuring mass
What is a physical change?
A change in state or shape without altering composition
Formation of new substances
A change in color only
A change in chemical composition
A physical change is characterized by:
Accompanied by light emission
The composition of the matter changes
Produces new substances
The composition of the matter does not change
How is heat transferred in fluids?
By insulation
What indicates a chemical reaction when sugar is burned?
It becomes harder
It changes color and emits smoke
It melts
It dissolves
Why are houses in hot areas painted white?
To reflect heat
To absorb heat
To store heat
To conduct heat
What is a chemical reaction?
A change in temperature
A process where new substances are formed
A change in state
A change in shape
Is the expansion of water in a sealed bottle in a freezer a chemical reaction?
Yes, because it changes state
Yes, because it changes volume
No, because no new substance is formed
No, because it is reversible
How is heat transferred through ironing clothes?
What indicates a chemical reaction between baking soda and vinegar?
Color change
Temperature decrease
Gas bubbles
Formation of a precipitate
Which of the following is a chemical change?
Melting ice
Burning wood
Breaking glass
Dissolving sugar
When sugar is heated, it turns brown due to:
Condensation
What is the scientific term for a change that produces new substances?
Chemical change
Physical change
Reversible change
Temporary change
What is thermal equilibrium?
When two systems have the same volume
When two systems have the same mass and same temperature
When two systems have the same density
When two systems have the same temperature
Why are cooling systems used in electronic devices?
To remove excess heat
To reduce noise
To increase performance
To increase weight
In which case is heat transferred only by radiation?
Heating water on a stove
Rubbing hands together
Heating air in the room with a radiator
Heating a rock by the Sun
What happens when an ice cube is placed in boiling water?
Heat flows from water to ice
Heat flows from ice to water
Ice gains energy from surroundings
No heat flows
What do all hot objects emit?
Sound waves
Infrared radiation
Light only
Ultraviolet rays
Which is NOT an indicator of a chemical reaction?
Change in texture
Emission of odor
Change in volume
Which is a good heat insulator?
Iron
Which type of clothing is preferred in summer?
Light and loose
Dark and tight
Shiny and thick
Black and heavy
What indicates a chemical reaction when oil reacts with caustic soda?
Emission of light
Gas evolution
Formation of a solid
How is heat transferred from the Sun to the Earth?
By reflection
What safety precaution is needed when burning magnesium?
Use water to cool it
Use bare hands
Use a plastic container
Use a protective mask