Terms in this set (32)
What is the simplest type of pure substance?
Can an element or simplest type of pure substance be broken down into simpler substances?
What are pure substances that are made of more than one element called?
How is a compound different from an element?
compounds can be broken down into chemical elements by chemical means
Is water a compound?
What two elements can water be broken into?
hydrogen and oxygen
What two elements is table salt broken into?
sodium and chloride
Other than chemical means, what is another way to separate compounds into their elements?
How is water broken down into hydrogen and oxygen?
by passing electric currents through water
What elements would you obtain passing an electric current through melted table salt?
sodium and chloride
The properties of the elements that make-up a compound are often quite different from the properties of the compound itself.
What are most compounds made of?
When oxygen is combined with rusting or burning, what process takes place?
What is made up of two or more atoms chemically bonded together?
What is a combination of chemical symbols or a shorthand way of representing substances?
What two things does a chemical formula tell us about a compound?
tells elements and how many atoms of each element
How do you write a chemical formula?
use a symbol for each element and a subscript
What is the term used for the number of atoms for an element?
Do most chemical formulas represent compounds?
What is the formula for carbon dioxide?
What happens during a chemical process or reaction?
substances are rearranged and become new and different substances
What is a description of a chemical reaction using symbols and formulas?
How can you describe a chemical reaction?
by using chemical symbols and formulas- chemical equation
When brushing your teeth, a chemical reaction occurs. What two things are combined? and What is released?
water and baking soda in toothpaste release oxygen
Why must a chemical equation be balanced?
atoms can only be rearranged because can't be created or destroyed
The number placed in front of a chemical formula in an equations is called?
What is used to balance and equation?
Do subscripts balance equations
Balance this H2 + O2= H2O
16P 40 O