What type of oxide is $H_{2}O$?

State whether the following statement is true or false:
Copper does not burn in air, but the hot metal is coated with a black-coloured layer of copper $(II)$ oxide.

Which of the following is $NOT$ the correct order of reactivity of metals?

Which metal catches fire when kept exposed to air?

What is the typical carat value of gold used in jewelry?

What is ammonia $(NH_3)$?