Elements, Compunds and Mixtures
What element is represented by Ca?
Calcium
What is the smallest component of an element, the basic unit of life?
atom
Compound or element
HCl
Compound
How many atoms does O₃ have?
3
C₂HCaOHC₂₂
How many atoms in the equation above?
24
How are the elements represented? How are they written?
Chemical symbols
What is a substance made of two or more different elements?
Compound
How many oxygens are there?
C₃H₄O₇
7
How many elements does
NaCl have?
2
Which of the following from the list are compounds?
a. NaCH3O2
b. O
c. Ca
d. CH2O4
A and D,
Bonus: How many elements are in NaCHO?
How many atoms are in CH2O4
What is a substance made of two or more atoms?
molecule
Which of these substances are considered molecules?
O₂
CO₂
Cu
Ne
O₂
Describe the chemical formula: Co(NO₂)₄ tell me how many atoms there are of each element.
Co-1
N-4
O-8
What characteristics describe an element? Circle all correct answers.
1. Elements are pure substances.
2. Elements are written with lowercase letters.
3.Elements are represented with chemical symbols.
4. Elements make up matter on Earth.
5. Elements are mixtures.
6. Elements are written with chemical formulas.
1, 3 and 4.
How many elements are in the compound NaClO₂?
3
Subscripts in a chemical formula represent:
the ratio of the number of atoms of each element present in the chemical formula
Which of the compounds contain the same number of oxygen atoms?
1. H₂SO₄
2. Fe₂O₃
3. Ca(ClO₂)₂
4. Mg(NO)₂
5. H₂O
1 and 3
How many hydrogens does the chemical formula have?
C₃H₅N₁₀OH₃