Which of the following is a characteristic property of matter that could be used to identify an unknown substance? • mass
• density
•volume
•temperature

physical properties

Explanation:

the characteristics (properties) that can be observed without changing the identity of a substance

Examples of physical properties

mass, color, size, volume, texture, density, state of matter, boiling point, melting point

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.