Question

true or false

1. elements are the simplest substances.
2. electrical energy is stored in the bonds that hold atoms together.
3. in a physical change, matter changes into a new kind of matter.
4. thermal energy flows from warmer objects to cooler objects.
5. electrical energy is the energy of moving charged particles.

using science skills
use the diagram below to answer questions 21 and 22.

1. interpreting diagrams look at each diagram. which diagram is a compound?

a. diagram a
b. diagram b
c. diagram c

1. interpreting diagrams which diagram is a mixture?

a. diagram a
b. diagram b
c. diagram c

Explanation:

1. Elements are the simplest substances as they cannot be broken down into simpler substances by chemical means. So, it's True.
2. Chemical energy is stored in the bonds that hold atoms together, not electrical energy. So, it's False.
3. In a physical change, matter does not change into a new kind of matter. Only its physical properties like shape, state, etc. change. So, it's False.
4. Thermal energy always flows from warmer objects to cooler objects according to the second - law of thermodynamics. So, it's True.
5. Electrical energy is the energy of moving charged particles. So, it's True.

For 21, a compound consists of two or more different types of atoms chemically bonded together. Diagram C shows groups of atoms of different types bonded, so it is a compound.
For 22, a mixture contains two or more different substances that are not chemically combined. Diagram B shows different types of particles just mixed together without chemical bonding, so it is a mixture.

Answer:

1. True
2. False
3. False
4. True
5. True
6. c. diagram C
7. b. diagram B