21. The ability of a substance to catch fire and burn is known as:
a) Reactivity
b) Conductivity
c) Solubility
d) Flammability
22. Which property refers to the ability of a substance to be drawn into thin wires?
a) Malleability
b) Ductility
c) Elasticity
d) Hardness
23. The property of a substance that allows it to be hammered into thin sheets is known as:
a) Malleability
b) Ductility
c) Elasticity
d) Hardness
24. The property of a substance that allows it to return to its original shape after being stretched or compressed is called:
a) Malleability
b) Ductility
c) Elasticity
d) Hardness
25. Which property refers to the resistance of a material to being scratched or indented?
a) Malleability
b) Ductility
c) Elasticity
d) Hardness