Front

What are elements?

Back

Elements are pure substances that cannot be broken down into simpler substances by chemical means. They consist of only one type of atom.

Front

What is a chemical reaction?

Back

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another, involving the breaking and forming of bonds.

Front

What evidence indicates a chemical reaction has occurred?

Back

Evidence of a chemical reaction includes the production of gas, a color change, the formation of a precipitate, or a temperature change.

Front

What is the net force?

Back

Net force is the overall force acting on an object after all the individual forces are combined. It determines the object's motion.

Front

How do you calculate net force?

Back

Net force is calculated by subtracting the opposing forces from the applied force. For example, if an applied force is 10 N and friction is 4 N, the net force is 10 N - 4 N = 6 N.

Front

What is the role of nitrogen dioxide in the environment?

Back

Nitrogen dioxide (NO₂) is a significant air pollutant that can contribute to smog and respiratory problems. It is produced from vehicle emissions and industrial processes.

Front

What is the significance of the tilt of the Earth?

Back

The tilt of the Earth (approximately 23.5 degrees) is responsible for the changing seasons as it affects the angle and intensity of sunlight received in different regions.

Front

What are physical properties of substances?

Back

Physical properties are characteristics that can be observed or measured without changing the substance's chemical identity, such as color, density, and melting point.

Front

What is friction?

Back

Friction is a force that opposes the motion of an object. It occurs when two surfaces interact and can affect the net force acting on an object.

Front

What is the difference between a gas and a solid?

Back

A gas has no fixed shape or volume and fills its container, while a solid has a definite shape and volume.