bro i need to lock in for chem

Question 1

Physical change

Answer 1

no new substance is made
There is a change in the appearance of a chemical. E.g. State change, dissolving.

Question 2

Chemical change

Answer 2

New substances are made. Chemical reactions normally have a change in appearance (e.g. colour) and energy changes (e.g. heat, light, sound).

Question 3

Explain Mentos reaction

Answer 3

The explosion was caused by a sudden increase in volume (gas) and a huge transfer of energy to the surroundings.
Physical changes can cause natural explosions as well eg Geysers and volcanoes.

Question 4

Explain atoms in chemical change?

Answer 4

Atoms in the reactants are rearranged to form new products with different properties

Question 5

Conservation of mass

Answer 5

mass is never lost or gained in chemical reactions

Question 6

Factors of particale theory

Answer 6

All matter is made up of tiny particles.
- particles are moving all the time.
- forces of attraction holding the particles together.
-forces vary in strength in different states of matter.
- particles have different amounts of energy and react different under pressure

Question 7

How can pressure be increased?

Answer 7

• Increasing the number of particles;
• Reducing the size of the container;
• Increasing the temperature

This is because the number of collisions with the sides of the container will increase.