Question

1. reactivity, as a chemical property, refers to the ability of a substance to:

be easily molded into different shapes.
exist in different states of matter.
maintain a constant temperature.
undergo a chemical reaction with another substance.

1. potassium is known to react vigorously with water, producing hydrogen gas and heat. this behavior is best described as a demonstration of potassiums:

flammability.
solubility.
reactivity
density

1. consider the following unbalanced chemical equation: mg(s) + o₂(g) → mgo(s).

Explanation:

• For question 5, reactivity is the ability of a substance to undergo a chemical - reaction with another substance. The other options describe physical properties like malleability (ability to be molded), states of matter, and thermal properties.
• For question 6, potassium reacting vigorously with water to produce hydrogen gas and heat shows its reactivity with water. Flammability is related to burning in air, solubility is about dissolving in a solvent, and density is mass per unit volume.

Answer:

1. Undergo a chemical reaction with another substance.
2. Reactivity