Question

subscript
yield
products
reactant
open - system
closed - system
malleability
ductility
melting point
boiling point
density
oxidation
flammability
toxicity
combustibility
endothermic reaction
exothermic reaction
q. a substance that takes part in and undergoes change in a reaction
p. ability of a material to be drawn into wires
q. temperature at which a solid turns into a liquid
r. a change that affects a substances appearance but not its composition
s. number that tells how many atoms of each element are in a compound
t. temperature at which a substance changes from liquid to gas
u. new substances formed as a result of a chemical reaction
v. matter is not allowed to enter or leave the system
w. a chemical change involving oxygen, such as rusting
x. ability of a substance to burn easily or ignite
y. reaction that releases heat to its surroundings
z. the amount of harm a substance can cause to organisms
aa. a substance, typically a liquid, that dissolves another substance
ab. number in front of a compound indicating amount of molecules
ac. ability of a substance to catch fire and burn
ad. a reaction that absorbs heat from its surroundings
ae. ability of a substance to be observed or measured without changing its identity

Explanation:

Match the terms on the left - hand side with their corresponding definitions on the right - hand side based on chemical concepts.
Subscript: S. Number that tells how many atoms of each element are in a compound.
Yield: No match provided in the right - hand side.
Products: U. New substances formed as a result of a chemical reaction.
Reactant: Q. A substance that takes part in and undergoes change in a reaction.
Open - system: No match provided in the right - hand side.
Closed - system: V. Matter is not allowed to enter or leave the system.
Malleability: No match provided in the right - hand side.
Ductility: P. Ability of a material to be drawn into wires.
Melting point: R. Temperature at which a solid turns into a liquid.
Boiling point: T. Temperature at which a substance changes from liquid to gas.
Density: No match provided in the right - hand side.
Oxidation: W. A chemical change involving oxygen, such as rusting.
Flammability: X. Ability of a substance to burn easily or ignite.
Toxicity: Z. The amount of harm a substance can cause to organisms.
Combustibility: AC. Ability of a substance to catch fire and burn.
Endothermic reaction: AD. A reaction that absorbs heat from its surroundings.
Exothermic reaction: Y. Reaction that releases heat to its surroundings.

Answer:

Subscript: S. Number that tells how many atoms of each element are in a compound
Products: U. New substances formed as a result of a chemical reaction
Reactant: Q. A substance that takes part in and undergoes change in a reaction
Closed - system: V. Matter is not allowed to enter or leave the system
Ductility: P. Ability of a material to be drawn into wires
Melting point: R. Temperature at which a solid turns into a liquid
Boiling point: T. Temperature at which a substance changes from liquid to gas
Oxidation: W. A chemical change involving oxygen, such as rusting
Flammability: X. Ability of a substance to burn easily or ignite
Toxicity: Z. The amount of harm a substance can cause to organisms
Combustibility: AC. Ability of a substance to catch fire and burn
Endothermic reaction: AD. A reaction that absorbs heat from its surroundings
Exothermic reaction: Y. Reaction that releases heat to its surroundings