Elements, Compounds and Mixtures Flashcards
(13 cards)
Define an element
A pure substance made up of only one type of atom.
What is the most common element in the air?
Nitrogen (about 78%).
How are atoms arranged in solids?
Tightly packed.
How do atoms in gases often exist?
In pairs, as diatomic molecules.
Define a compound
A substance made of two or more different elements that are chemically bonded together.
Can you easily separate elements in a compound?
No, it’s very difficult.
How do the properties of compounds compare to the original elements?
They are often completely different.
How can mixtures be separated?
By physical methods like distillation.
Define a mixture
A combination of two or more substances that are not chemically joined together.
Do mixtures keep the properties of their components?
Yes, they show a mix of individual properties.
What makes a substance pure in chemistry?
It’s made entirely of one element or one compound.
What is special about the melting and boiling points of pure substances?
They have sharp, specific melting and boiling points.
Do mixtures have sharp melting or boiling points?
No, they change gradually over a range of temperatures.
